采用糙皮侧耳真菌的菌丝体来替代传统的化学粘合剂来粘结废棉纤维并通过一定的后加工处理制备质轻环保的废棉纤维生物复合板材,并通过添加废旧烟梗和烟叶作为骨架材料来增强其压缩强度。实验结果表明,添加了不同骨架材料的棉纤维生物复...采用糙皮侧耳真菌的菌丝体来替代传统的化学粘合剂来粘结废棉纤维并通过一定的后加工处理制备质轻环保的废棉纤维生物复合板材,并通过添加废旧烟梗和烟叶作为骨架材料来增强其压缩强度。实验结果表明,添加了不同骨架材料的棉纤维生物复合板抗压载荷和压缩弹性模量都优于废棉纤维生物复合板;厚度为20 mm的废棉纤维生物复合板在合理的压缩范围内的抗压载荷达到12.35 k N,而添加了烟叶和烟梗的废棉纤维生物复合板的抗压载荷分别达到了10.16 k N和27.10 k N;最终制成的三种不同的生物复合材料其压缩弹性模量最高达到22.40 MPa,赋予了该生物复合材料特殊的静态压缩特性。展开更多
Municipal solid waste （MSW） and its disposal are gaining significant importance in geotechnical and geoenvironmental engineering. However, conventional research is primarily focused on fresh MSW or MSW that is compa...Municipal solid waste （MSW） and its disposal are gaining significant importance in geotechnical and geoenvironmental engineering. However, conventional research is primarily focused on fresh MSW or MSW that is compacted under its own weight in the landfill. In this work, a series of tests to study the properties of a densified MSW after ground treatment were presented. The tests involved oedometer test, simple shear test, triaxial shear test, and permeability test, which were conducted to investigate the compressibility, shear strength, creep behavior and permeability of the MSW. The results show that the compressibility modulus of the MSW increases as the dry density increases. However, the influence of density on modulus decreases once the density reaches a certain value. Like most soils, the stress-strain curve of the densified MSW can be approximated by a hyperbola in the triaxial shear test. Fibrous components provide additional cohesion for MSW, but have a relatively smaller effect on friction angle. Permeability is also found to be closely related to the dry density of the MSW, i.e., MSW with a higher dry density has a smaller permeability. The permeability coefficient may be less than 10 7 cm/s if the density is high enough.展开更多
Based on fluid mechanics, thermodynamics and damage mechanics, thermal-hydro-mechanical （THM） coupling damage model of brittle rock is established by analyzing THM coupling mechanism, where THM coupling damage varia...Based on fluid mechanics, thermodynamics and damage mechanics, thermal-hydro-mechanical （THM） coupling damage model of brittle rock is established by analyzing THM coupling mechanism, where THM coupling damage variable DTHM is dominated by TH coupling damage variable DTH, TM coupling damage variable DTM and HM coupling damage variable DHM, and DTH is firstly expressed in term of dimensionless total thermal conductivity of the water Nu. Permeability test, uni-axial compression test and THM coupling test are conducted to measure the permeability, elastic modulus and THM coupling stress-strain curves of brittle rock. The tested values of THM coupling elastic modulus E＇HM are in good agreement with the predicted values of THM coupling elastic modulus ETHM, which can verify the newly established THM coupling damage model.展开更多
Wax-coated sands are a new category of synthetic soils, which are gradually becoming a reliable construction material. Because of their valuable drainage ability and mechanical properties, wax coated sandy soils are s...Wax-coated sands are a new category of synthetic soils, which are gradually becoming a reliable construction material. Because of their valuable drainage ability and mechanical properties, wax coated sandy soils are specifically applicable to pavement construction of horseracing tracks and sport fields. Although the mechanical and hydraulic properties of these synthetic soils are well-proven, there is still a lack of studies on how the soil samples behave differently when mixing with different wax fractions. Adding the wax affects permeability and compressibility of pure sand. Intensity of influences is a function of weight percentage of wax that has been added, and other physical and environmental factors. The effects of wax content on hydraulic properties(permeability), and mechanical properties(stress strain behavior, compressibility) of sandy soils based on a series of experimental efforts were investigated. Obtained experimental results infer that increasing the amount of wax up to 6% causes an about 50% increase in permeability, mainly because of the significant effect of wax in lowering the friction along with covering and filling the angular parts of particles' surfaces and forming rounded particles. In addition, wax-coated sands show a 20% to 60% decrease in confined compression modulus compared to non wax-coated sands.展开更多
To investigate the mechanical properties of cement mortar in sodium sulfate and sodium chloride solutions, uniaxial compression test and ultrasonic test were performed. Test results show that the relative dynamic elas...To investigate the mechanical properties of cement mortar in sodium sulfate and sodium chloride solutions, uniaxial compression test and ultrasonic test were performed. Test results show that the relative dynamic elastic modulus, the mass variation,and the compressive strength of cement mortar increase first, and then decrease with increasing erosion time in sodium sulfate and sodium chloride solutions. The relative dynamic elastic moduli and the compressive strengths of cement mortars with water/cement ratios of 0.55 and 0.65 in sodium sulfate solution are lower than those in sodium chloride solution with the same concentration at the420 th day of immersion. The compressive strength of cement mortar with water/cement ratio of 0.65 is more sensitive to strain rate than that with water/cement ratio of 0.55. In addition, the strain-rate sensitivity of compressive strength of cement mortar will increase under attacks of sodium sulfate or sodium chloride solution.展开更多
文摘采用糙皮侧耳真菌的菌丝体来替代传统的化学粘合剂来粘结废棉纤维并通过一定的后加工处理制备质轻环保的废棉纤维生物复合板材,并通过添加废旧烟梗和烟叶作为骨架材料来增强其压缩强度。实验结果表明,添加了不同骨架材料的棉纤维生物复合板抗压载荷和压缩弹性模量都优于废棉纤维生物复合板;厚度为20 mm的废棉纤维生物复合板在合理的压缩范围内的抗压载荷达到12.35 k N,而添加了烟叶和烟梗的废棉纤维生物复合板的抗压载荷分别达到了10.16 k N和27.10 k N;最终制成的三种不同的生物复合材料其压缩弹性模量最高达到22.40 MPa,赋予了该生物复合材料特殊的静态压缩特性。
基金Foundation item： Project（50979047） supported by the National Natural Science Foundation of China Project（2010CB732103） supported by the National Basic Research Program of China Project（2012-KY-02） supported by the State Key Laboratory of Hydroscience and Engineering （Tsinghua University）, China
文摘Municipal solid waste （MSW） and its disposal are gaining significant importance in geotechnical and geoenvironmental engineering. However, conventional research is primarily focused on fresh MSW or MSW that is compacted under its own weight in the landfill. In this work, a series of tests to study the properties of a densified MSW after ground treatment were presented. The tests involved oedometer test, simple shear test, triaxial shear test, and permeability test, which were conducted to investigate the compressibility, shear strength, creep behavior and permeability of the MSW. The results show that the compressibility modulus of the MSW increases as the dry density increases. However, the influence of density on modulus decreases once the density reaches a certain value. Like most soils, the stress-strain curve of the densified MSW can be approximated by a hyperbola in the triaxial shear test. Fibrous components provide additional cohesion for MSW, but have a relatively smaller effect on friction angle. Permeability is also found to be closely related to the dry density of the MSW, i.e., MSW with a higher dry density has a smaller permeability. The permeability coefficient may be less than 10 7 cm/s if the density is high enough.
基金Project(11072269) supported by the National Natural Science Foundation of ChinaProject(20090162110066) supported by the Research Fund for the Doctoral Program of Higher Education of China
文摘Based on fluid mechanics, thermodynamics and damage mechanics, thermal-hydro-mechanical （THM） coupling damage model of brittle rock is established by analyzing THM coupling mechanism, where THM coupling damage variable DTHM is dominated by TH coupling damage variable DTH, TM coupling damage variable DTM and HM coupling damage variable DHM, and DTH is firstly expressed in term of dimensionless total thermal conductivity of the water Nu. Permeability test, uni-axial compression test and THM coupling test are conducted to measure the permeability, elastic modulus and THM coupling stress-strain curves of brittle rock. The tested values of THM coupling elastic modulus E＇HM are in good agreement with the predicted values of THM coupling elastic modulus ETHM, which can verify the newly established THM coupling damage model.
文摘Wax-coated sands are a new category of synthetic soils, which are gradually becoming a reliable construction material. Because of their valuable drainage ability and mechanical properties, wax coated sandy soils are specifically applicable to pavement construction of horseracing tracks and sport fields. Although the mechanical and hydraulic properties of these synthetic soils are well-proven, there is still a lack of studies on how the soil samples behave differently when mixing with different wax fractions. Adding the wax affects permeability and compressibility of pure sand. Intensity of influences is a function of weight percentage of wax that has been added, and other physical and environmental factors. The effects of wax content on hydraulic properties(permeability), and mechanical properties(stress strain behavior, compressibility) of sandy soils based on a series of experimental efforts were investigated. Obtained experimental results infer that increasing the amount of wax up to 6% causes an about 50% increase in permeability, mainly because of the significant effect of wax in lowering the friction along with covering and filling the angular parts of particles' surfaces and forming rounded particles. In addition, wax-coated sands show a 20% to 60% decrease in confined compression modulus compared to non wax-coated sands.
基金Project(LY13E080021) supported by the Natural Science Foundation of Zhejiang Province,ChinaProject(2011A610072) supported by the Ningbo Municipal Natural Science Foundation,ChinaProject(XKL14D2063) supported by Subject Program of Ningbo University,China
文摘To investigate the mechanical properties of cement mortar in sodium sulfate and sodium chloride solutions, uniaxial compression test and ultrasonic test were performed. Test results show that the relative dynamic elastic modulus, the mass variation,and the compressive strength of cement mortar increase first, and then decrease with increasing erosion time in sodium sulfate and sodium chloride solutions. The relative dynamic elastic moduli and the compressive strengths of cement mortars with water/cement ratios of 0.55 and 0.65 in sodium sulfate solution are lower than those in sodium chloride solution with the same concentration at the420 th day of immersion. The compressive strength of cement mortar with water/cement ratio of 0.65 is more sensitive to strain rate than that with water/cement ratio of 0.55. In addition, the strain-rate sensitivity of compressive strength of cement mortar will increase under attacks of sodium sulfate or sodium chloride solution.
