The objective of this work is to obtain the seismic safety coefficient and fracture surface and proceed with the seismic safety evaluation for the rock mass or soil mass surrounding a tunnel,and the limitation of eval...The objective of this work is to obtain the seismic safety coefficient and fracture surface and proceed with the seismic safety evaluation for the rock mass or soil mass surrounding a tunnel,and the limitation of evaluating seismic stability is considered using the pseudo-static strength reduction.By using the finite element software ANSYS and the strength reduction method,new methods of seismic safety evaluation for the rock mass or soil mass surrounding a tunnel are put forward,such as the dynamic finite element static shear strength reduction method and dynamic finite element shear strength reduction method.In order to prove the feasibility of the proposed methods,the results of numerical examples are compared with that of the pseudo-static strength reduction method.The results show that 1) the two methods are both feasible,and the plastic zone first appears near the bottom corners; 2) the safety factor of new method Ⅱ is smaller than that of new method I but generally,and the difference is very small.Therefore,in order to ensure the safety of the structure,two new methods are proposed to evaluate the seismic stability of the rock mass or soil mass surrounding a tunnel.A theoretical basis is provided for the seismic stability of the rock mass or soil mass and the lining surrounding a tunnel and also provided for the engineering application.展开更多
以乌鲁木齐1号线穿越急倾斜煤层采空区为原型,借助物理相似试验引入分形理论开展荷载下采空区覆岩动态演化规律及其质量评价研究。结果表明:随着采场推进,覆岩最大应力增加且伴随升维现象;利用双重分形定量描述覆岩裂隙状态变化,荷载0.2...以乌鲁木齐1号线穿越急倾斜煤层采空区为原型,借助物理相似试验引入分形理论开展荷载下采空区覆岩动态演化规律及其质量评价研究。结果表明:随着采场推进,覆岩最大应力增加且伴随升维现象;利用双重分形定量描述覆岩裂隙状态变化,荷载0.20~0.35 MPa时产生新裂隙,且原有裂隙会闭合;裂隙条数分形维数与地表最大下沉量及侧壁围岩最大离层量呈非线性相关,荷载0.20 MPa时均有较大跳跃,变化趋势一致;建立基于岩体完整性系数和岩体损伤程度的岩体质量评价方法,对采动和地铁荷载工况下覆岩岩体质量进行评价,发现RMR(Rock Mass Rating)值随分维数增大呈线性递减趋势,并量化表征了岩体力学参数和岩体质量的弱化程度。研究结果可为穿越采空区的路基稳定性评价提供科学依据。展开更多
基金Project(2011CB013600) supported by State Key Program for Basic Research of ChinaProject(20136201110003) supported by the Education Ministry Doctoral Tutor Foundation of China+1 种基金Project(51368039) supported by the National Natural Science Foundation of ChinaProject(2013-4-94) supported by the Program of Science and Technology Research in Lanzhou City,China
文摘The objective of this work is to obtain the seismic safety coefficient and fracture surface and proceed with the seismic safety evaluation for the rock mass or soil mass surrounding a tunnel,and the limitation of evaluating seismic stability is considered using the pseudo-static strength reduction.By using the finite element software ANSYS and the strength reduction method,new methods of seismic safety evaluation for the rock mass or soil mass surrounding a tunnel are put forward,such as the dynamic finite element static shear strength reduction method and dynamic finite element shear strength reduction method.In order to prove the feasibility of the proposed methods,the results of numerical examples are compared with that of the pseudo-static strength reduction method.The results show that 1) the two methods are both feasible,and the plastic zone first appears near the bottom corners; 2) the safety factor of new method Ⅱ is smaller than that of new method I but generally,and the difference is very small.Therefore,in order to ensure the safety of the structure,two new methods are proposed to evaluate the seismic stability of the rock mass or soil mass surrounding a tunnel.A theoretical basis is provided for the seismic stability of the rock mass or soil mass and the lining surrounding a tunnel and also provided for the engineering application.
文摘以乌鲁木齐1号线穿越急倾斜煤层采空区为原型,借助物理相似试验引入分形理论开展荷载下采空区覆岩动态演化规律及其质量评价研究。结果表明:随着采场推进,覆岩最大应力增加且伴随升维现象;利用双重分形定量描述覆岩裂隙状态变化,荷载0.20~0.35 MPa时产生新裂隙,且原有裂隙会闭合;裂隙条数分形维数与地表最大下沉量及侧壁围岩最大离层量呈非线性相关,荷载0.20 MPa时均有较大跳跃,变化趋势一致;建立基于岩体完整性系数和岩体损伤程度的岩体质量评价方法,对采动和地铁荷载工况下覆岩岩体质量进行评价,发现RMR(Rock Mass Rating)值随分维数增大呈线性递减趋势,并量化表征了岩体力学参数和岩体质量的弱化程度。研究结果可为穿越采空区的路基稳定性评价提供科学依据。
