To study the rolling motion of a ship in the presence of water on its deck,a linear-plus-quadratic damping term was incorporated into its equation of motion.Ship model tests indicates that the key dynamics of the phys...To study the rolling motion of a ship in the presence of water on its deck,a linear-plus-quadratic damping term was incorporated into its equation of motion.Ship model tests indicates that the key dynamics of the physical system are preserved in the ship rolling equation with the linear-plus-quadratic type damping term.To take into account the presence of randomness in the excitation and the response,a new method was developed and a Melnikov criterion was obtained to provide an upper bound on the domain of the potential chaotic rolling motion(erratic rocking).Additionally,the Melnikov criterion proposed in this study was verified by the utilization of phase plane diagrams and Poincare maps.Furthermore,this research has made the initial endeavor to systematically modify the system parameters in the rolling equation of motion for ship stability analysis.展开更多
In mining the left-over coal above the gob,stope wall rock of mining area have hard limestone.through field observation,the face-contacted block structure was found in rocks between coal seams to mine the left-over co...In mining the left-over coal above the gob,stope wall rock of mining area have hard limestone.through field observation,the face-contacted block structure was found in rocks between coal seams to mine the left-over coal above the gob.In order to probe into the movement law of rock strata and strata control measures,it is very important to identify the mobile block in face-contacted block structure of rocks between coal seams.This paper relies on the thought of block theory to establish appropriate parameter matrix and figure out its discrimination matrix in view of the fact that the block in face-contacted block structure has high intensity and stiffness,the展开更多
Marmarosh massif is an important structural element of the Eastern Carpathians,which differs by the geological features from the other structural-facial zones of Carpathian fold belt.Metamorphic rocks of the massif ha...Marmarosh massif is an important structural element of the Eastern Carpathians,which differs by the geological features from the other structural-facial zones of Carpathian fold belt.Metamorphic rocks of the massif have been formed under the influence of the processes of medium-and low-temperature meta-morphism and metasomatism.Within the Marmarosh massif the stratiform gold ore has展开更多
A combination of mineralogical and multielement analyses was used to characterize the hydrothermal alteration,pathfinder elements and their distribution within the gold deposits in North Mara mines,the Archean Musoma-...A combination of mineralogical and multielement analyses was used to characterize the hydrothermal alteration,pathfinder elements and their distribution within the gold deposits in North Mara mines,the Archean Musoma-Mara greenstone belt,Tanzania. The aim was to evaluate the suitability of alteration mineral assemblages and composition as an effective exploration marker for fingerprinting展开更多
Genetically diverse lithologies, which include blueschist, greenschist, ultramafic, mafic plutonic, e.g. gabbros, and volcanic, e.g. pillowed basalts, and metasedimentary rocks, occur as a wedge\|shaped zone in the ar...Genetically diverse lithologies, which include blueschist, greenschist, ultramafic, mafic plutonic, e.g. gabbros, and volcanic, e.g. pillowed basalts, and metasedimentary rocks, occur as a wedge\|shaped zone in the area to the north of the Mingora town in Swat, NW Pakistan. This zone of fault\|bounded rock bodies and blocks is distinguished into three principal groups, each of which is itself a composite of lithologies, or a melange—the blueschist melange, greenschist melange and ophiolitic melange. All these lie along the Main Mantle Thrust (MMT)—the westward extension of the Indus\|Tsangbo suture zone and the locus of collision between the Indo\|Pakistan plate and the Kohistan island arc—and, are therefore, collectively termed as the Main Mantle Thrust Melange Group (MMTMG).The ultramafic rocks, locally containing chromite pods and constituting a part of the ophiolitic member of the MMTMG, occur as small to large lenticular bodies, distributed along the marginal part of the Indo\|Pakistan plate. They are invariably serpentinized to varying degrees and, therefore, consist of abundant, fine grained serpentine which is mostly accompanied by subordinate amounts of completely bastitised, medium to coarse grained orthopyroxene, trace to accessory amounts of commonly altered (zoned with ferritchromite and/or magnetite) chrome spinel, variable proportions of olivine, and accessory amounts of diopside. In other words, the ultramafic rocks are mostly harzburgitic in mineralogy and, therefore, the ophiolite as a whole can be classified as the harzburgite sub\|type..Detailed field and mineralogical studies show that the present petrographic ch aracteristics and mineral\|chemical composition of these dominantly harburgitic rocks are the result of a number of phenomena involving partial melting, serpentinization, metamorphism and talc\|carbonate alteration.展开更多
The Panxi Rift Zone is a famous metallogenic province in Southwest China. Continental rifting developed in Hercynian period (P 2, 260～250Ma) accompany with a series of basic\|ultrabasic rocks. Various in lithologies,...The Panxi Rift Zone is a famous metallogenic province in Southwest China. Continental rifting developed in Hercynian period (P 2, 260～250Ma) accompany with a series of basic\|ultrabasic rocks. Various in lithologies, such as layered intrusions (V\|Ti\|Fe formation), small\|sized mafic\|ultramafic bodies (stocks) and large\|scale basalt (Emeishan Basalt) are constituted of a complete melanocratic rock system.Most of Cu\|Ni\|PGE sulfide deposits are related to small\|sized ultramafic rock bodies. It is a perfect possibility for them to be an affinity of basic eruptive lava and for the neck facies. But in ① Panzhihua\|Center Yunnan Province, the Gaojiacun, also Jinbaoshan, as large stratiform basic\|ultrabasic complex used to be thought that is older one intruded to basement rocks in Precambrian. However, new evidences suggest it is similar with the small\|sized ultramafic rock bodies containing Cu\|Ni\|PGE, and also the both are affinity of the Emeishan Basalt; ② Miyi district, Cu\|Pt mineralization was discovered in the Xinjie bedded basic complex, and in where ophitic olivine\|pyroxenite\|peridotite facies are exactly Pt\|bearing layers; ③ Longzhoushan district, we have recently researched basic\|ultrabasic clusters which intruded into fracture zones, and Cu\|Ni\|Pt, Pd mineralization developed at the salbands.Generally, the basalt is poor in PGE and rich in Cu. It is suggested as the result of PGE dispersion\|concentration processing in the melanocratic rock system when rifting happened.展开更多
Rock fracture warning is one of the significant challenges in rock mechanics.Many true triaxial and synchronous acoustic emission(AE)tests were conducted on granite samples.The investigation focused on the characteris...Rock fracture warning is one of the significant challenges in rock mechanics.Many true triaxial and synchronous acoustic emission(AE)tests were conducted on granite samples.The investigation focused on the characteristics of AE signals preceding granite fracture,based on the critical slowing down(CSD)theory.The granite undergoes a transition from the stable phase to the fracture phase and exhibits a clear CSD phenomenon,characterized by a pronounced increase in variance and autocorrelation coefficient.The variance mutation points were found to be more identifiable and suitable as the primary criterion for predicting precursor information related to granite fracture,compared to the autocorrelation coefficient.It is noteworthy to emphasize that the CSD factor holds greater potential in elucidating the underlying mechanisms responsible for the critical transition of granite fracture,in comparison to the AE timing parameters.Furthermore,a novel multi-parameter collaborative prediction method for rock fracture was developed by comprehensively analyzing predictive information,including abnormal variation modes and the CSD factor of AE characteristic parameters.This method enhances the understanding and prediction of rock fracture-related geohazards.展开更多
This paper developed a statistical damage constitutive model for deep rock by considering the effects of external load and thermal treatment temperature based on the distortion energy.The model parameters were determi...This paper developed a statistical damage constitutive model for deep rock by considering the effects of external load and thermal treatment temperature based on the distortion energy.The model parameters were determined through the extremum features of stress−strain curve.Subsequently,the model predictions were compared with experimental results of marble samples.It is found that when the treatment temperature rises,the coupling damage evolution curve shows an S-shape and the slope of ascending branch gradually decreases during the coupling damage evolution process.At a constant temperature,confining pressure can suppress the expansion of micro-fractures.As the confining pressure increases the rock exhibits ductility characteristics,and the shape of coupling damage curve changes from an S-shape into a quasi-parabolic shape.This model can well characterize the influence of high temperature on the mechanical properties of deep rock and its brittleness-ductility transition characteristics under confining pressure.Also,it is suitable for sandstone and granite,especially in predicting the pre-peak stage and peak stress of stress−strain curve under the coupling action of confining pressure and high temperature.The relevant results can provide a reference for further research on the constitutive relationship of rock-like materials and their engineering applications.展开更多
The failure characteristics of thermal treated surrounding rocks should be studied to evaluate the stability and safety of deep ground engineering under high-ground-temperature and high-ground-stress conditions.The fa...The failure characteristics of thermal treated surrounding rocks should be studied to evaluate the stability and safety of deep ground engineering under high-ground-temperature and high-ground-stress conditions.The failure process of the inner walls of fine-grained granite specimens at different temperatures(25–600℃)was analyzed using a true-triaxial test system.The failure process,peak intensity,overall morphology(characteristics after failure),rock fragment characteristics,and acoustic emission(AE)characteristics were analyzed.The results showed that for the aforementioned type of granite specimens,the trend of the failure stress conditions changed with respect to the critical temperature(200℃).When the temperature was less than 200℃,the initial failure stress increased,final failure stress increased,and failure severity decreased.When the temperature exceeded 200℃,the initial failure stress decreased,final failure stress decreased,and failure severity increased.When the temperature was 600℃,the initial and final failure stresses of the specimens decreased by 60.93%and 19.77%compared with those at 200℃,respectively.The numerical results obtained with the software RFPA3D-Thermal were used to analyze the effect of temperature on the specimen and reveal the mechanism of the failure process in the deep tunnel surrounding rock.展开更多
A study was conducted to analyze the deformation mechanism of strongly weathered quartz schist in the Daliangshan Tunnel,located in the western Transverse Mountain area.A large deformation problem was experienced duri...A study was conducted to analyze the deformation mechanism of strongly weathered quartz schist in the Daliangshan Tunnel,located in the western Transverse Mountain area.A large deformation problem was experienced during the tunnel construction.To mitigate this problem,a support system was designed incorporating negative Poisson ratio(NPR)anchor cables with negative Poisson ratio effect.Physical model experiments,field experiments,and numerical simulation experiments were conducted to investigate the compensation mechanical behavior of NPR anchor cables.The large deformations of soft rocks in the Daliangshan Tunnel are caused by a high ground stress,a high degree of joint fracture development,and a high degree of surrounding rock fragmentation.A compensation mechanics support system combining long and short NPR anchor cables was suggested to provide sufficient counter-support force(approximately 350 kN)for the surrounding rock inside the tunnel.Comparing the NPR anchor cable support system with the original support system used in the Daliangshan tunnel showed that an NPR anchor cable support system,combining cables of 6.3 m and 10.3 m in length,effectively prevented convergence of surrounding rock deformation,and the integrated settlement convergence value remained below 300 mm.This study provides an effective scientific basis for resolving large deformation problems in deeply buried soft rocks in western transverse mountain areas.展开更多
Cenozoic volcanism has been well studied in northern, eastern and southwestern Tibet (Coulon et al., 1986; Arnund et al., 1992; Turner et al., 1993, 1996; Deng, 1978, 1998; Miller et al., 1999, Wang et al, 2000). But ...Cenozoic volcanism has been well studied in northern, eastern and southwestern Tibet (Coulon et al., 1986; Arnund et al., 1992; Turner et al., 1993, 1996; Deng, 1978, 1998; Miller et al., 1999, Wang et al, 2000). But the data of the Cenozoic post\|collisional volcanism in central and southern Tibet is limited (Coulon et al., 1986; Turner et al., 1996; Zhang, 1998). These potassic and ultrapotassic intrusive and extrusive rocks are regarded to be a key clue for the deep lithospheric process of the plateau after Indo\|Asian collision. Present here is the preliminary results of the rocks from Oiyug (Wuyu) basin, about 150km northeast to Shigatse. Major and trace elements of the rocks are studied and compared with the ultrapotassic and potassic (shoshonitic) rocks exposed in Lhasa block and Qiangtang terrane.(1) Geologic setting. The magmatic rocks studied are Gazacun formation of the lower part of the Pliocene Oiyug group (N 2 oy ). The cross\|section is situated in Gazacun village of Namling. Gazacun formation is underlain unconformable by the andesitic rocks of Linzizong Group [(K 2—E 2) ln ], and covered by the coarse\|grain layered sandstone and conglomerate of Zongdangcun formation. The Gazacun formation consists of mediate\|acidic volcanics, granite\|porphyry, coal\|bearing clastics, plants and sporo\|pollen.展开更多
The ilvaite-bearing skarn associations in the Galinge skarn deposit were studied to determine their physicochemical formation conditions.A thermodynamic model setting pressure of 50 MPa(Pf=Ps=50 MPa)was set up to trac...The ilvaite-bearing skarn associations in the Galinge skarn deposit were studied to determine their physicochemical formation conditions.A thermodynamic model setting pressure of 50 MPa(Pf=Ps=50 MPa)was set up to trace the skarn evolution.Petrographic evidence for replacement of garnet and magnetite by ilvaite in the early retrograde stage(Stage I)combined with thermodynamic modeling suggests that the alteration may have occurred at 400470°C under moderately high fO withΔlgfO(HM)ranges from 4 to 4.2.The model is based on a maximum 22 pressure of 50 MPa calculated from magmatic amphibole geobarometer.The continuous breakdown of ilvaite with quartz to form ferro-actinolite and magnetite occur in the late retrograde stage(Stage II).The reactions occurred at 400440°C under moderate fO(ΔlgfO(HM):4 to 4.4).In Stage III,the breakdown of ilvaite to form calcite,pyrite 22 and ferroactinolite depends on XCO which can be estimated to be in a range of 0.005 to 0.05,and the reaction would 2 occur at higher temperatures with increasing XCO.Under these conditions,the breakdown occurs at 270350°C and 2 low fO(ΔlgfO(HM):up to 5.2).The thermodynamic model for continuous evolution from Stage I to Stage III 22 completely records the conditions of the retrograde alteration,which is inconsistent with the thermobarometry imprints of fluid inclusions.Therefore,the petrography and phase relations of ilvaite are useful indicators of reaction conditions in various skarn deposit types.展开更多
Toppling failure of rock mass/soil slope is an important geological and environmental problem.Clarifying its failure mechanism under different conditions has great significance in engineering.The toppling failure of a...Toppling failure of rock mass/soil slope is an important geological and environmental problem.Clarifying its failure mechanism under different conditions has great significance in engineering.The toppling failure of a cutting slope occurred in a hydropower station in Kyushu,Japan illustrates that the joint characteristic played a significant role in the occurrence of rock slope tipping failure.Thus,in order to consider the mechanical properties of jointed rock mass and the influence of geometric conditions,a simplified analytical approach based on the limit equilibrium method for modeling the flexural toppling of cut rock slopes is proposed to consider the influence of the mechanical properties and geometry condition of jointed rock mass.The theoretical solution is compared with the numerical solution taking Kyushu Hydropower Station in Japan as one case,and it is found that the theoretical solution obtained by the simplified analysis method is consistent with the numerical analytical solution,thus verifying the accuracy of the simplified method.Meanwhile,the Goodman-Bray approach conventionally used in engineering practice is improved according to the analytical results.The results show that the allowable slope angle may be obtained by the improved Goodman-Bray approach considering the joint spacing,the joint frictional angle and the tensile strength of rock mass together.展开更多
Background and objective:Epidermal growth factor receptor(EGFR)mutations are often associated with non-EGFR genetic alterations,which maybe a reason for the poor efficacy of EGFR tyrosine kinase inhibitors(TKIs).Here ...Background and objective:Epidermal growth factor receptor(EGFR)mutations are often associated with non-EGFR genetic alterations,which maybe a reason for the poor efficacy of EGFR tyrosine kinase inhibitors(TKIs).Here we conducted this study to explore whether EGFR-TKIs combined with chemotherapy would benefit advanced lung adenocarcinoma patients with both sensitive EGFR mutation and concomitant non-EGFR genetic alterations.Materials and methods:Cases of advanced lung adenocarcinoma with EGFR mutation combined with concomitant nonEGFR genetic alterations were retrospectively collected.And the patients were required to receive first-line EGFR-TKIs and chemotherapy combination or EGFR-TKIs monotherapy.Demographic,clinical and pathological data were collected,and the electronic imaging data were retrieved to evaluate the efficacy and time of disease progression.Survival data were obtained through face-to-face or telephone follow-up.The differences between the two groups in objective response rate(ORR),disease control rate(DCR),progression-free survival(PFS)and overall survival(OS)were investigated.Results:107 patients were included,including 63 cases in the combination group and 44 cases in the monotherapy group.The ORR were 78%and 50%(P=0.003),and DCR were 97%and 77%(P=0.002),respectively.At a median follow-up of 13.7 mon,a PFS event occurred in 38.1%and 81.8%of patients in the two groups,with median PFS of18.8 mon and 5.3 mon,respectively(P<0.000,1).Median OS was unreached in the combination group,and 27.8 mon in the monotherapy group(P=0.31).According to the Cox multivariate regression analysis,combination therapy was an independent prognostic factor of PFS.Conclusion:In patients with EGFR-mutant advanced lung adenocarcinoma with concomitant non-EGFR genetic alterations,combination of TKIs and chemotherapy was significantly superior to EGFR-TKIs monotherapy,which should be the preferred treatment option.展开更多
Based on the relationship between rock physical properties and atomic structures of chemical elements, this paper dissertates the characteristics between the difference and change in the comprehensive physical propert...Based on the relationship between rock physical properties and atomic structures of chemical elements, this paper dissertates the characteristics between the difference and change in the comprehensive physical properties of rocks, such as density, elasticity, electrical property and radioactivity, etc. The examples in this paper show that the change of the comprehensive physical parameters of rocks reflects the change of atoms, molecules, minerals and their constitutions in rocks, and there are some correlations between these parameters.展开更多
In this paper we present petrology and geochemistry from a range of metasomatically altered rocks within the Eastern Gawler Craton mineralised province of South Australia.The rocks represent four protolith types;grani...In this paper we present petrology and geochemistry from a range of metasomatically altered rocks within the Eastern Gawler Craton mineralised province of South Australia.The rocks represent four protolith types;granite,basalt,non-carbonate metasediment and calc-silicate metasediment.Alteration paragenesis varies in intensity and between the protolith types.I.The alteration paragenesis of granites has the first pervasive chlorite and the second filled hematite with two generations of chalcopyrite.After the展开更多
Blasting-induced cracks in the rock surrounding deeply buried tunnels can result in water gushing and rock mass collapse,posing significant safety risks.However,previous theoretical studies on the range of blasting-in...Blasting-induced cracks in the rock surrounding deeply buried tunnels can result in water gushing and rock mass collapse,posing significant safety risks.However,previous theoretical studies on the range of blasting-induced cracks often ignore the impact of the in-situ stress,especially that of the intermediate principal stress.The particle displacement−crack radius relationship was established in this paper by utilizing the blasthole cavity expansion equation,and theoretical analytical formulas of the stress−displacement relationship and the crack radius were derived with unified strength theory to accurately assess the range of cracks in deep surrounding rock under a blasting load.Parameter analysis showed that the crushing zone size was positively correlated with in-situ stress,intermediate principal stress,and detonation pressure,whereas negatively correlated with Poisson ratio and decoupling coefficient.The dilatancy angle-crushing zone size relationship exhibited nonmonotonic behavior.The relationships in the crushing zone and the fracture zone exhibited opposite trends under the influence of only in-situ stress or intermediate principal stress.As the in-situ stress increased from 0 to 70 MPa,the rate of change in the crack range and the attenuation rate of the peak vibration velocity gradually slowed.展开更多
The deep buried clastic formation of Paleogene is an important hydrocarbon reservoir in the Chezhen depression.There are two types of diagenetic alteration modes in it.The first mode is weak compaction, strong cementa...The deep buried clastic formation of Paleogene is an important hydrocarbon reservoir in the Chezhen depression.There are two types of diagenetic alteration modes in it.The first mode is weak compaction, strong cementation,fracturing and weak dissolution in the sandstone and conglomerate on the steep slope of the depression.The reservoirs are cemented mainly by carbonate minerals strongly。展开更多
The Cenozoic volcanic rocks in Qinghai—Tibetan plateau mainly occur in Qiangtang, Kunlun,Kokshili and eastern Tibet to the north of Bangong\|Nujiang suture. The study area locates in the centre of Qiangtang (N34°...The Cenozoic volcanic rocks in Qinghai—Tibetan plateau mainly occur in Qiangtang, Kunlun,Kokshili and eastern Tibet to the north of Bangong\|Nujiang suture. The study area locates in the centre of Qiangtang (N34°00′\|34°50′;E87°30′\|89°00′),where is nearly a blank area of geological work.Thirteen pieces of samples from Hehulin,Luanqingshan,Bandaohu and Donghu show that the K\|Ar ages of the Cenozoic volcanic rocks range from 32 6 to 44 1Ma, which are elder than the Cenozoic volcanic rocks from Kunlun,Kokshili and eastern Tibet.There are two types of occurrence for the volcanic rocks: volcanic lava and sub\|volcanic rock. The lava is dark grey, light purple or dark purple and unconformably covers up on the Jurassic,which interbeds with purplish red tertiary sandstone and pebble\|bearing sandstone and contains a small amount of phenocrysts (andesine,pyroxene,amphibole and biotite). three craters and four volcanic necks have been found in this area. The sub\|volcanic rocks expose as volcanic necks with appearance of isolated peaks,which intrude into Jurassic. The rocks,appearing grey white to light grey, have trachytic texture with the phenocrysts of plagioclase,biotite and amphibole. Besides above rocks,there are some lamprophyre dikes intruding into grey white tertiary lacustrine algal limestone in this area with its length up to 2km and width 3m. The rocks appear dark grey or dark green and contain the phenocrysts of pyroxene,orthoclase,biotite,olivine,and leucitite.展开更多
According to many researchers,it is the dispersed organic matter in the process of catagenesis that enables to generate additional and sometimes significant amounts of hydrocarbons.The heterogeneous composition of the...According to many researchers,it is the dispersed organic matter in the process of catagenesis that enables to generate additional and sometimes significant amounts of hydrocarbons.The heterogeneous composition of the dispersed organic matter of the Permian rocks is characterized by various generation possibilities.In conducting展开更多
文摘To study the rolling motion of a ship in the presence of water on its deck,a linear-plus-quadratic damping term was incorporated into its equation of motion.Ship model tests indicates that the key dynamics of the physical system are preserved in the ship rolling equation with the linear-plus-quadratic type damping term.To take into account the presence of randomness in the excitation and the response,a new method was developed and a Melnikov criterion was obtained to provide an upper bound on the domain of the potential chaotic rolling motion(erratic rocking).Additionally,the Melnikov criterion proposed in this study was verified by the utilization of phase plane diagrams and Poincare maps.Furthermore,this research has made the initial endeavor to systematically modify the system parameters in the rolling equation of motion for ship stability analysis.
文摘In mining the left-over coal above the gob,stope wall rock of mining area have hard limestone.through field observation,the face-contacted block structure was found in rocks between coal seams to mine the left-over coal above the gob.In order to probe into the movement law of rock strata and strata control measures,it is very important to identify the mobile block in face-contacted block structure of rocks between coal seams.This paper relies on the thought of block theory to establish appropriate parameter matrix and figure out its discrimination matrix in view of the fact that the block in face-contacted block structure has high intensity and stiffness,the
文摘Marmarosh massif is an important structural element of the Eastern Carpathians,which differs by the geological features from the other structural-facial zones of Carpathian fold belt.Metamorphic rocks of the massif have been formed under the influence of the processes of medium-and low-temperature meta-morphism and metasomatism.Within the Marmarosh massif the stratiform gold ore has
文摘A combination of mineralogical and multielement analyses was used to characterize the hydrothermal alteration,pathfinder elements and their distribution within the gold deposits in North Mara mines,the Archean Musoma-Mara greenstone belt,Tanzania. The aim was to evaluate the suitability of alteration mineral assemblages and composition as an effective exploration marker for fingerprinting
文摘Genetically diverse lithologies, which include blueschist, greenschist, ultramafic, mafic plutonic, e.g. gabbros, and volcanic, e.g. pillowed basalts, and metasedimentary rocks, occur as a wedge\|shaped zone in the area to the north of the Mingora town in Swat, NW Pakistan. This zone of fault\|bounded rock bodies and blocks is distinguished into three principal groups, each of which is itself a composite of lithologies, or a melange—the blueschist melange, greenschist melange and ophiolitic melange. All these lie along the Main Mantle Thrust (MMT)—the westward extension of the Indus\|Tsangbo suture zone and the locus of collision between the Indo\|Pakistan plate and the Kohistan island arc—and, are therefore, collectively termed as the Main Mantle Thrust Melange Group (MMTMG).The ultramafic rocks, locally containing chromite pods and constituting a part of the ophiolitic member of the MMTMG, occur as small to large lenticular bodies, distributed along the marginal part of the Indo\|Pakistan plate. They are invariably serpentinized to varying degrees and, therefore, consist of abundant, fine grained serpentine which is mostly accompanied by subordinate amounts of completely bastitised, medium to coarse grained orthopyroxene, trace to accessory amounts of commonly altered (zoned with ferritchromite and/or magnetite) chrome spinel, variable proportions of olivine, and accessory amounts of diopside. In other words, the ultramafic rocks are mostly harzburgitic in mineralogy and, therefore, the ophiolite as a whole can be classified as the harzburgite sub\|type..Detailed field and mineralogical studies show that the present petrographic ch aracteristics and mineral\|chemical composition of these dominantly harburgitic rocks are the result of a number of phenomena involving partial melting, serpentinization, metamorphism and talc\|carbonate alteration.
文摘The Panxi Rift Zone is a famous metallogenic province in Southwest China. Continental rifting developed in Hercynian period (P 2, 260～250Ma) accompany with a series of basic\|ultrabasic rocks. Various in lithologies, such as layered intrusions (V\|Ti\|Fe formation), small\|sized mafic\|ultramafic bodies (stocks) and large\|scale basalt (Emeishan Basalt) are constituted of a complete melanocratic rock system.Most of Cu\|Ni\|PGE sulfide deposits are related to small\|sized ultramafic rock bodies. It is a perfect possibility for them to be an affinity of basic eruptive lava and for the neck facies. But in ① Panzhihua\|Center Yunnan Province, the Gaojiacun, also Jinbaoshan, as large stratiform basic\|ultrabasic complex used to be thought that is older one intruded to basement rocks in Precambrian. However, new evidences suggest it is similar with the small\|sized ultramafic rock bodies containing Cu\|Ni\|PGE, and also the both are affinity of the Emeishan Basalt; ② Miyi district, Cu\|Pt mineralization was discovered in the Xinjie bedded basic complex, and in where ophitic olivine\|pyroxenite\|peridotite facies are exactly Pt\|bearing layers; ③ Longzhoushan district, we have recently researched basic\|ultrabasic clusters which intruded into fracture zones, and Cu\|Ni\|Pt, Pd mineralization developed at the salbands.Generally, the basalt is poor in PGE and rich in Cu. It is suggested as the result of PGE dispersion\|concentration processing in the melanocratic rock system when rifting happened.
基金Project(52074294)supported by the National Natural Science Foundation of ChinaProject(2022YJSNY16)supported by the Fundamental Research Funds for the Central Universities,China。
文摘Rock fracture warning is one of the significant challenges in rock mechanics.Many true triaxial and synchronous acoustic emission(AE)tests were conducted on granite samples.The investigation focused on the characteristics of AE signals preceding granite fracture,based on the critical slowing down(CSD)theory.The granite undergoes a transition from the stable phase to the fracture phase and exhibits a clear CSD phenomenon,characterized by a pronounced increase in variance and autocorrelation coefficient.The variance mutation points were found to be more identifiable and suitable as the primary criterion for predicting precursor information related to granite fracture,compared to the autocorrelation coefficient.It is noteworthy to emphasize that the CSD factor holds greater potential in elucidating the underlying mechanisms responsible for the critical transition of granite fracture,in comparison to the AE timing parameters.Furthermore,a novel multi-parameter collaborative prediction method for rock fracture was developed by comprehensively analyzing predictive information,including abnormal variation modes and the CSD factor of AE characteristic parameters.This method enhances the understanding and prediction of rock fracture-related geohazards.
基金Project(11272119)supported by the National Natural Science Foundation of China。
文摘This paper developed a statistical damage constitutive model for deep rock by considering the effects of external load and thermal treatment temperature based on the distortion energy.The model parameters were determined through the extremum features of stress−strain curve.Subsequently,the model predictions were compared with experimental results of marble samples.It is found that when the treatment temperature rises,the coupling damage evolution curve shows an S-shape and the slope of ascending branch gradually decreases during the coupling damage evolution process.At a constant temperature,confining pressure can suppress the expansion of micro-fractures.As the confining pressure increases the rock exhibits ductility characteristics,and the shape of coupling damage curve changes from an S-shape into a quasi-parabolic shape.This model can well characterize the influence of high temperature on the mechanical properties of deep rock and its brittleness-ductility transition characteristics under confining pressure.Also,it is suitable for sandstone and granite,especially in predicting the pre-peak stage and peak stress of stress−strain curve under the coupling action of confining pressure and high temperature.The relevant results can provide a reference for further research on the constitutive relationship of rock-like materials and their engineering applications.
基金Project(52174098)supported by the National Natural Science Foundation of ChinaProject(2022JJ20063)supported by the Natural Science Foundation of Hunan Province,ChinaProject(2023CXQD011)supported by the Fundamental Research Funds for the Central Universities,China。
文摘The failure characteristics of thermal treated surrounding rocks should be studied to evaluate the stability and safety of deep ground engineering under high-ground-temperature and high-ground-stress conditions.The failure process of the inner walls of fine-grained granite specimens at different temperatures(25–600℃)was analyzed using a true-triaxial test system.The failure process,peak intensity,overall morphology(characteristics after failure),rock fragment characteristics,and acoustic emission(AE)characteristics were analyzed.The results showed that for the aforementioned type of granite specimens,the trend of the failure stress conditions changed with respect to the critical temperature(200℃).When the temperature was less than 200℃,the initial failure stress increased,final failure stress increased,and failure severity decreased.When the temperature exceeded 200℃,the initial failure stress decreased,final failure stress decreased,and failure severity increased.When the temperature was 600℃,the initial and final failure stresses of the specimens decreased by 60.93%and 19.77%compared with those at 200℃,respectively.The numerical results obtained with the software RFPA3D-Thermal were used to analyze the effect of temperature on the specimen and reveal the mechanism of the failure process in the deep tunnel surrounding rock.
基金Project(41941018)supported by the National Natural Science Foundation of China for the Special Project FundingProject(22-JKCF-08)supported by the Study on in-situ Stress Database and 3D in-situ Stress Inversion Technology of Highway Tunnel in Shanxi Province,China+1 种基金Project(2022-JKKJ-6)supported by the Study on Disaster Mechanism and NPR Anchor Cable Prevention and Control of Coal Mining Caving Subsidence in Operating Tunnel in Mountainous Area,ChinaProject(BBJ2024032)supported by the Fundamental Research Funds for the Central Universities(PhD Top Innovative Talents Fund of CUMTB),China。
文摘A study was conducted to analyze the deformation mechanism of strongly weathered quartz schist in the Daliangshan Tunnel,located in the western Transverse Mountain area.A large deformation problem was experienced during the tunnel construction.To mitigate this problem,a support system was designed incorporating negative Poisson ratio(NPR)anchor cables with negative Poisson ratio effect.Physical model experiments,field experiments,and numerical simulation experiments were conducted to investigate the compensation mechanical behavior of NPR anchor cables.The large deformations of soft rocks in the Daliangshan Tunnel are caused by a high ground stress,a high degree of joint fracture development,and a high degree of surrounding rock fragmentation.A compensation mechanics support system combining long and short NPR anchor cables was suggested to provide sufficient counter-support force(approximately 350 kN)for the surrounding rock inside the tunnel.Comparing the NPR anchor cable support system with the original support system used in the Daliangshan tunnel showed that an NPR anchor cable support system,combining cables of 6.3 m and 10.3 m in length,effectively prevented convergence of surrounding rock deformation,and the integrated settlement convergence value remained below 300 mm.This study provides an effective scientific basis for resolving large deformation problems in deeply buried soft rocks in western transverse mountain areas.
文摘Cenozoic volcanism has been well studied in northern, eastern and southwestern Tibet (Coulon et al., 1986; Arnund et al., 1992; Turner et al., 1993, 1996; Deng, 1978, 1998; Miller et al., 1999, Wang et al, 2000). But the data of the Cenozoic post\|collisional volcanism in central and southern Tibet is limited (Coulon et al., 1986; Turner et al., 1996; Zhang, 1998). These potassic and ultrapotassic intrusive and extrusive rocks are regarded to be a key clue for the deep lithospheric process of the plateau after Indo\|Asian collision. Present here is the preliminary results of the rocks from Oiyug (Wuyu) basin, about 150km northeast to Shigatse. Major and trace elements of the rocks are studied and compared with the ultrapotassic and potassic (shoshonitic) rocks exposed in Lhasa block and Qiangtang terrane.(1) Geologic setting. The magmatic rocks studied are Gazacun formation of the lower part of the Pliocene Oiyug group (N 2 oy ). The cross\|section is situated in Gazacun village of Namling. Gazacun formation is underlain unconformable by the andesitic rocks of Linzizong Group [(K 2—E 2) ln ], and covered by the coarse\|grain layered sandstone and conglomerate of Zongdangcun formation. The Gazacun formation consists of mediate\|acidic volcanics, granite\|porphyry, coal\|bearing clastics, plants and sporo\|pollen.
基金Projects(41172076,41802080)supported by the National Natural Science Foundation of ChinaProject(1212011085528)supported by Geological Survey Program from the China Geological Survey+3 种基金Project(2019CX035)supported by Innovation-driven Plan of Central South University,ChinaProject(201411025)supported by the Scientific Research Fund from Ministry of Land and Re-sources,ChinaProject(201309)supported by the Program of High-level Geological Talents,ChinaProject(201112)supported by the Youth Geological Talents of the China Geological Survey
文摘The ilvaite-bearing skarn associations in the Galinge skarn deposit were studied to determine their physicochemical formation conditions.A thermodynamic model setting pressure of 50 MPa(Pf=Ps=50 MPa)was set up to trace the skarn evolution.Petrographic evidence for replacement of garnet and magnetite by ilvaite in the early retrograde stage(Stage I)combined with thermodynamic modeling suggests that the alteration may have occurred at 400470°C under moderately high fO withΔlgfO(HM)ranges from 4 to 4.2.The model is based on a maximum 22 pressure of 50 MPa calculated from magmatic amphibole geobarometer.The continuous breakdown of ilvaite with quartz to form ferro-actinolite and magnetite occur in the late retrograde stage(Stage II).The reactions occurred at 400440°C under moderate fO(ΔlgfO(HM):4 to 4.4).In Stage III,the breakdown of ilvaite to form calcite,pyrite 22 and ferroactinolite depends on XCO which can be estimated to be in a range of 0.005 to 0.05,and the reaction would 2 occur at higher temperatures with increasing XCO.Under these conditions,the breakdown occurs at 270350°C and 2 low fO(ΔlgfO(HM):up to 5.2).The thermodynamic model for continuous evolution from Stage I to Stage III 22 completely records the conditions of the retrograde alteration,which is inconsistent with the thermobarometry imprints of fluid inclusions.Therefore,the petrography and phase relations of ilvaite are useful indicators of reaction conditions in various skarn deposit types.
基金Project(52109132)supported by the National Natural Science Foundation of ChinaProject(ZR2020QE270)supported by the Natural Science Foundation of Shandong Province,China+1 种基金Project(JMDPC202204)supported by State Key Laboratory of Strata Intelligent Control,Green Mining Co-founded by Shandong Province and the Ministry of Science and TechnologyShandong University of Science and Technology,China。
文摘Toppling failure of rock mass/soil slope is an important geological and environmental problem.Clarifying its failure mechanism under different conditions has great significance in engineering.The toppling failure of a cutting slope occurred in a hydropower station in Kyushu,Japan illustrates that the joint characteristic played a significant role in the occurrence of rock slope tipping failure.Thus,in order to consider the mechanical properties of jointed rock mass and the influence of geometric conditions,a simplified analytical approach based on the limit equilibrium method for modeling the flexural toppling of cut rock slopes is proposed to consider the influence of the mechanical properties and geometry condition of jointed rock mass.The theoretical solution is compared with the numerical solution taking Kyushu Hydropower Station in Japan as one case,and it is found that the theoretical solution obtained by the simplified analysis method is consistent with the numerical analytical solution,thus verifying the accuracy of the simplified method.Meanwhile,the Goodman-Bray approach conventionally used in engineering practice is improved according to the analytical results.The results show that the allowable slope angle may be obtained by the improved Goodman-Bray approach considering the joint spacing,the joint frictional angle and the tensile strength of rock mass together.
文摘Background and objective:Epidermal growth factor receptor(EGFR)mutations are often associated with non-EGFR genetic alterations,which maybe a reason for the poor efficacy of EGFR tyrosine kinase inhibitors(TKIs).Here we conducted this study to explore whether EGFR-TKIs combined with chemotherapy would benefit advanced lung adenocarcinoma patients with both sensitive EGFR mutation and concomitant non-EGFR genetic alterations.Materials and methods:Cases of advanced lung adenocarcinoma with EGFR mutation combined with concomitant nonEGFR genetic alterations were retrospectively collected.And the patients were required to receive first-line EGFR-TKIs and chemotherapy combination or EGFR-TKIs monotherapy.Demographic,clinical and pathological data were collected,and the electronic imaging data were retrieved to evaluate the efficacy and time of disease progression.Survival data were obtained through face-to-face or telephone follow-up.The differences between the two groups in objective response rate(ORR),disease control rate(DCR),progression-free survival(PFS)and overall survival(OS)were investigated.Results:107 patients were included,including 63 cases in the combination group and 44 cases in the monotherapy group.The ORR were 78%and 50%(P=0.003),and DCR were 97%and 77%(P=0.002),respectively.At a median follow-up of 13.7 mon,a PFS event occurred in 38.1%and 81.8%of patients in the two groups,with median PFS of18.8 mon and 5.3 mon,respectively(P<0.000,1).Median OS was unreached in the combination group,and 27.8 mon in the monotherapy group(P=0.31).According to the Cox multivariate regression analysis,combination therapy was an independent prognostic factor of PFS.Conclusion:In patients with EGFR-mutant advanced lung adenocarcinoma with concomitant non-EGFR genetic alterations,combination of TKIs and chemotherapy was significantly superior to EGFR-TKIs monotherapy,which should be the preferred treatment option.
文摘Based on the relationship between rock physical properties and atomic structures of chemical elements, this paper dissertates the characteristics between the difference and change in the comprehensive physical properties of rocks, such as density, elasticity, electrical property and radioactivity, etc. The examples in this paper show that the change of the comprehensive physical parameters of rocks reflects the change of atoms, molecules, minerals and their constitutions in rocks, and there are some correlations between these parameters.
文摘In this paper we present petrology and geochemistry from a range of metasomatically altered rocks within the Eastern Gawler Craton mineralised province of South Australia.The rocks represent four protolith types;granite,basalt,non-carbonate metasediment and calc-silicate metasediment.Alteration paragenesis varies in intensity and between the protolith types.I.The alteration paragenesis of granites has the first pervasive chlorite and the second filled hematite with two generations of chalcopyrite.After the
基金Project(2021JJ10063)supported by the Natural Science Foundation of Hunan Province,ChinaProject(202115)supported by the Science and Technology Progress and Innovation Project of Hunan Provincial Department of Transportation,ChinaProject(2021K094-Z)supported by the Science and Technology Research and Development Program of China Railway Guangzhou Group Co.,Ltd。
文摘Blasting-induced cracks in the rock surrounding deeply buried tunnels can result in water gushing and rock mass collapse,posing significant safety risks.However,previous theoretical studies on the range of blasting-induced cracks often ignore the impact of the in-situ stress,especially that of the intermediate principal stress.The particle displacement−crack radius relationship was established in this paper by utilizing the blasthole cavity expansion equation,and theoretical analytical formulas of the stress−displacement relationship and the crack radius were derived with unified strength theory to accurately assess the range of cracks in deep surrounding rock under a blasting load.Parameter analysis showed that the crushing zone size was positively correlated with in-situ stress,intermediate principal stress,and detonation pressure,whereas negatively correlated with Poisson ratio and decoupling coefficient.The dilatancy angle-crushing zone size relationship exhibited nonmonotonic behavior.The relationships in the crushing zone and the fracture zone exhibited opposite trends under the influence of only in-situ stress or intermediate principal stress.As the in-situ stress increased from 0 to 70 MPa,the rate of change in the crack range and the attenuation rate of the peak vibration velocity gradually slowed.
文摘The deep buried clastic formation of Paleogene is an important hydrocarbon reservoir in the Chezhen depression.There are two types of diagenetic alteration modes in it.The first mode is weak compaction, strong cementation,fracturing and weak dissolution in the sandstone and conglomerate on the steep slope of the depression.The reservoirs are cemented mainly by carbonate minerals strongly。
文摘The Cenozoic volcanic rocks in Qinghai—Tibetan plateau mainly occur in Qiangtang, Kunlun,Kokshili and eastern Tibet to the north of Bangong\|Nujiang suture. The study area locates in the centre of Qiangtang (N34°00′\|34°50′;E87°30′\|89°00′),where is nearly a blank area of geological work.Thirteen pieces of samples from Hehulin,Luanqingshan,Bandaohu and Donghu show that the K\|Ar ages of the Cenozoic volcanic rocks range from 32 6 to 44 1Ma, which are elder than the Cenozoic volcanic rocks from Kunlun,Kokshili and eastern Tibet.There are two types of occurrence for the volcanic rocks: volcanic lava and sub\|volcanic rock. The lava is dark grey, light purple or dark purple and unconformably covers up on the Jurassic,which interbeds with purplish red tertiary sandstone and pebble\|bearing sandstone and contains a small amount of phenocrysts (andesine,pyroxene,amphibole and biotite). three craters and four volcanic necks have been found in this area. The sub\|volcanic rocks expose as volcanic necks with appearance of isolated peaks,which intrude into Jurassic. The rocks,appearing grey white to light grey, have trachytic texture with the phenocrysts of plagioclase,biotite and amphibole. Besides above rocks,there are some lamprophyre dikes intruding into grey white tertiary lacustrine algal limestone in this area with its length up to 2km and width 3m. The rocks appear dark grey or dark green and contain the phenocrysts of pyroxene,orthoclase,biotite,olivine,and leucitite.
文摘According to many researchers,it is the dispersed organic matter in the process of catagenesis that enables to generate additional and sometimes significant amounts of hydrocarbons.The heterogeneous composition of the dispersed organic matter of the Permian rocks is characterized by various generation possibilities.In conducting
