地下采空区框架结构的变形研究

对地基采用D-P模型,地基和基础采用四边形单元,对上部结构采用梁单元,通过有限元计算方法地对采空区距建筑物的间距、采空区的深度、采空区的高度、采空区上覆岩层对框架结构的影响进行分析,采用考虑二阶矩的简化刚度法计算框架结构的挠度曲线和塑性铰出现的位置和顺序。计算结果表明,采空区在一定范围内的存在,对建筑物有很大影响,导致柱的剪力增大,塑性铰出现的顺序发生变化,结构的延性变差,同时也表明条形基础的抗采空影响能力要高于独立基础,并给出框架结构抗采空结构措施。

RESEARCH ON DEFORMATION OF FRAME STRUCTURES IN UNDERGROUND WORKING-OUT SECTION AREA

The D - P criterion is adopted as a constitutive relation of a foundation. The quadrangle element and beam element are also used. The effect of the distance away from buildings, the depth, the height and overburden in working-out section area is studied using FEM. The simplified stiffness matrix method considering the second matrix is used to calculate deformation, location and sequence of plastic hinges. The result shows that the working-out section area affects the frame structure greatly in a certain distance. When shear stress of column increases, the sequence of plastic hinge changes. The ductility of the structures changes into poor one. The result also shows the strip foundation is advantageous over the independence foundation. At last, some structure measures are suggested to protect the frame buildings.