桥涵顶进施工后背土抗力分析

Soil resistance of back in jacking construction of bridge and culvert

为深入分析顶进过程中后背受力变形特征及后背土体的应力、位移特性,针对某钢筋混凝土重力式后背,分别采用朗肯被动土压力理论和三维有限元分析,对顶力作用下后背的位移和土抗力进行对比分析;对影响后背结构的受力变形各因素进行了分析。结果表明:顶力合力作用点与后背土体抗力一致时,后背表现为整体移动;后背土抗力理论值较数值计算值偏大;后背原状土的弹模和强度指标对后背在最大顶进荷载下的变形影响较大。

In order to obtain the load-deformation characteristics of the back and the stress displacement of the back soil,a gravity back is analyzed and compared by passive earth pressure theory and the three-dimensional finite element analysis method,the displacement of the back and the resistance of the soil under the action of the jacking force are compared and analyzed,and the factors affecting the force and deformation of the back structure are analyzed,the results show that when the force acting on the top is consistent with the resistance of the back soil,the back shows the whole movement,the theoretical value of resistance of back soil is larger than that of numerical value,the elastic modulus and strength of the back soil have great influence on the deformation of the back under the maximum jacking load.