静载荷试验确定复合地基承载力的安全储备研究

A Safety Reserve Index Evaluating the Bearing Capacity of Composite Foundation Based on Loading Test

未加载充分的现场静载荷试验不能完全反映地基承载力情况,有可能导致复合地基安全储备过高。结合闽东沿海某工程,在静载荷试验未加载充分的情况下,利用灰色模型预测了单桩和复合地基的极限承载力。同时,定义复合地基承载力极限值与按相对变形确定的特征值之比为K,K是一个反映复合地基承载力安全储备的安全系数。通过统计同地区113组复合地基静载荷试验结果,确定了水泥土搅拌桩复合地基的K值。经过验证,K值同样适用于该工程。因此K具有一定地区性,在根据相对变形确定复合地基承载力特征值后,利用K可以一定程度上预测复合地基承载力极限值,从而为较直观认知复合地基的安全储备提供参考。

In some projects there are restrictions in static loading tests and thus the characteristic load bearing capacity is unable to be determined. Through analyzing a project of cement-soil pile composite foundation,the ultimate bearing capacity of the piles and composite foundation is predicted with 'gray model'under limited test conditions. Meanwhile,the ratio of the bearing capacity to the characteristic bearing capacity determined from relative deformation is defined as safety reserve index 'K',and 113 groups of static loading test are analyzed to obtain the K value of this region. The statistical result is confirmed by the project. It should be noticed that K is a regional and experiential value,and it can be used to predict the ultimate bearing capacity of cement-soil pile composite foundation based on the known bearing capacity determined by relative deformation.