考虑基坑坑内有限土体被动土压力研究  

Study on Passive Earth Pressure of Finite Soil in Foundation Pits

作　　者：喻卫华 Yu Weihua(Guangzhou Municipal Group Co.,Ltd.,Guangzhou 510620,China)

机构地区：[1]广州市市政集团有限公司,广东广州510620

出　　处：《市政技术》2024年第6期75-80,134,共7页Journal of Municipal Technology

摘　　要：通过数据分析,定量研究了坑内是否考虑有限土体对基坑支护结构位移和弯矩等的影响,并根据极限平衡理论推导了坑内有限土体被动土压力的计算表达式,分析了土体黏聚力、土体内摩擦角、支护与土体间外摩擦角以及有限土体坡脚变化时坑内有限土体被动土压力的变化情况。研究结果表明:坑内有限土体在实际工程中不能仅作为安全储备,应充分考虑其有利作用;被动土压力会随着黏聚力、内摩擦角、外摩擦角和坡脚的增大而增大,土体的破裂角会随着内摩擦角、外摩擦角、坡脚的增大而减小;在黏聚力值相同的条件下,当坑内有限土体宽度与高度比值逐渐增大时,破裂角也逐渐增大;当坑内有限土体宽度与高度比值相同时,黏聚力越大,对应的破裂角也越大;当坑内有限土体宽度与高度比值>1.0后,随着比值的增大,黏聚力值越小,破裂角的增幅越大;当坑内有限土体宽度与高度比值>1.2时,可以将坑内有限土体视为无限土体,可按照经典土压力理论进行求解。Through data analysis,the influence of limited soil on the displacement and bending moment of the foundation pit support structure was quantitatively studied.Based on the limit equilibrium theory,the calculation expression for the passive soil pressure of the limited soil in the pit was derived.The changes of the passive soil pressure of the limited soil in the pit were analyzed with changes in soil cohesion,internal friction angle,external friction angle between support and soil and the slope foot of the limited soil.The research results indicate that the limited soil in the pit can’t only be solely used as a safety reserve in practical engineering,but its beneficial effects should be fully considered;The passive soil pressure will increase with the increase of cohesion,internal friction angle,external friction angle,and slope foot.While the rupture angle of the soil will decrease with the increase of internal friction angle,external friction angle,and slope foot;When the cohesion value is the same,with the ratio increase of the width to height of the limited soil gradually increases,the fracture angle also gradually increases;When the ratio of width to height ratio of the limited soil is the same,the greater the cohesive force,the greater the corresponding fracture angle;When the ratio of the width to height of the limited soil is greater than 1.0,with the ratio increases,the smaller the cohesion value,and the larger the fracture angle increases;When the ratio of the width to height of the limited soil is greater than 1.2,the limited soil in the pit can be considered as infinite soil and be solved by the classical soil pressure theory.

关 键 词：基坑 有限土体 被动土压力 

分 类 号：TU443[建筑科学—岩土工程]