基于Terzaghi极限承载力理论的PLT边载效应分析

浅层平板载荷试验(PLT)广泛应用于土木工程中浅部地基土层承载力的评定,试验过程中承压板周围覆土边载有可能对地基承载力评定造成影响。基于极限平衡理论,推导出广义边载分布条件下Terzaghi极限承载力公式,通过调整浅层平板载荷试验(PLT)承压板周围边载的范围和大小,分别针对砂土和黏性土地基,分析边载效应对地基极限承载力的影响大小和变化规律。结合工程实例,指出在工程应用中最终边载效应对处理后地基土的影响程度须结合PLT试验过程中土体最终达到的应力状态做出综合判断。

Analysis of side load effect on PLT based on Terzaghi ultimate bearing capacity theory

Shallow plate loading test(PLT)is widely applied in civil engineering for evaluation of subsoil bearing capacity.Side load due to soil around loading plate may influence the judgment of subsoil bearing capacity.Based on limit equilibrium theory,we derive Terzaghi ultimate bearing capacity formula under a more generalized side load distribution condition.By adjusting magnitude and distribution of side load around loading plate in PLT,we analyze side load effect on ultimate subsoil bearing capacity respectively for sand and cohesive soil foundation.Combined with an engineering case,we point out that side load effect on determination of wether allowed subsoil bearing capacity should be judged on fully consideration of soil stress state reached in the process of PLT.