小尺度井结构基坑墙后土压力的坑角效应

Corner effect of active earth pressure for small-sized excavation

摘要:

为研究小尺度井结构基坑墙后土压力的坑角效应，通过对井结构基坑进行室内模型试验及FLAC^3d数值模拟，研究了井结构基坑墙后土压力的空间分布和墙后土压力坑角效应对围护结构内力的影响，分析了基坑尺度对墙后土压力坑角效应的影响规律.结果表明：1.5H深度以内墙后土压力分布具有坑角效应，且不同尺寸井结构基坑坑角效应的影响范围在离坑角0.2H以内；坑角效应使得角部水泥土剪应力较大；当L/H(主墙长度与挖深之比)≤1.5时，坑角效应主要受L/H的影响；L/B(主墙长度与附墙长度之比)对坑角效应影响不显著.

Abstract:

To study the corner effect of the earth pressure for small-sized excavation, the spatial distribution of active earth pressure was studied for excavations with different sizes, using laboratory model test and the FLAC^3d respectively. The influences of L/H (L is the length of primary wall; H is the excavation depth) and L/B (B is the length of complementary wall) on the significance of corner effect were also analyzed. The results show that: the distribution of active soil pressure displays the effect of corners in the depth of 1.5H; the distance affected by the corner effect is almost the same (within 0.2H from the corner) for different sizes of excavations; the shear stress in cement-stabilised soil is greater on the corner section because of the existence of the corner effect; for relatively small L/H, the significance of corner effect is mainly affected by L/H; the significance of corner effect seems to be independent of L/B.