深厚软土中长短桩复合地基试验  

Experimental study of long-short piles composite foundation in deep soft soils

作　　者：张可能[1] 杨庆光[1] 刘杰[2] 

机构地区：[1]中南大学地学与环境工程学院,湖南长沙410083 [2]湖南工业大学岩土工程研究所,湖南株洲412008

出　　处：《煤田地质与勘探》2008年第2期32-35,39,共5页Coal Geology & Exploration

基　　金：国家自然科学基金项目(50578169)

摘　　要：为了研究水泥土长短桩复合地基在深厚软土的加固效果及其承载特性,实测了长桩、短桩和桩间土顶面应力,探讨了这种复合地基桩土应力比及其变化规律。研究表明,长桩和短桩桩土应力比均表现为先增大,后减小,再趋于稳定的趋势,并在临界荷载Pc前后,复合地基主次桩顺序发生变化。得出考虑荷载水平的水泥土长短桩复合地基承载力计算公式及桩土承载力发挥系数取值方法。结果表明:β取值范围在0.778～0.838,β2的取值范围为0.945～0.971,并且建议取s/b比值为0.001 48～0.002 04对应的承载力为长短桩复合地基承载力特征值。For researching reinforcement effect and bearing characteristics of long-short cement-soil piles compos- ite foundation in deep soft soils, the test in situ on the bearing characteristics of long-short cement-soil piles composite ground in deep soft soils are carried out. The stresses of long piles, short piles and soil are measured; and pile-soil stress ratio of composite ground with cement-soil long-short piles and its variation with the load in deep soils are also studied. According to pile-soil stress ratio, it has been found that stress ratio increases at first and then decreases and finally tend to stability. It is revealed that the sequence of primary piles and secondary pile are changed after reaching critical load Pc. Based on the result of static load test, computational formulas for bearing capacity characteristic value and bearing capacity coefficient of cement-soil long-short piles composite foundation which have thought of load level are developed in this paper. Result indicates that the value of β ranges 0.778-0.838, β2 is 0.945-0.971. It is suggested that when s/b is 0.00148-0.00204 the value of-bearing capasity is bearing capacity characteristics of cement-soil long-short piles composite foundation.

关 键 词：水泥土桩 长短桩 复合地基 承载特性 载荷试验 

分 类 号：TU473.1[建筑科学—结构工程]