钢纤维管片接头局部应力的数值模拟试验

为评价少筋钢纤维混凝土管片接头的力学性能以便于工程中推广应用,对管片接头及手孔在施工及使用阶段的局部应力进行了三维非线性有限元数值模拟试验。内容包括:①施工阶段,千斤顶作用下管片的局部抗压性能;②施工阶段,盾构均匀推进及纠偏工况时管片变形及环缝上的应力、应变分布;③使用阶段,使用荷载作用下管片体、纵缝的变形及应力分布。结果表明:不论在施工阶段还是使用阶段,管片体、接头的主压应力均在允许范围内,但接头榫头局部主拉应力偏大,超出了钢纤维混凝土的抗拉强度,设计时需要加强;而手孔部位的局部主拉应力较小,均在控制应力范围之内。

Numerical modeling tests on local stress of SFRC tunnel segment joints

In order to evaluate the mechanical behavior of segment joints of steel fiber reinforced concrete segment(SFRC segment) used in subway tunnel,3D FEM numerical tests were conducted to model the local stress conditions of segment joint.The scope of the analysis involved: ① the performance of the segment against the thrust forces of shield jacking in construction stage,② the stress and strain distributions of segment body and circumferential joints in construction stages;③ the stress and strain distributions of segment body and longitudinal joints in service stage.It was shown that compression stresses of segments and joints both in construction and service stages met the requirements of design.It should be noticed that,the maximum tension stress and strain of rabbets of joints were much larger than the critical stress and strain of concrete.It was suggested that the rabbets should be reinforced more in design.Further more,tension stress near handhole was in the range of designed value.