高应力下水泥粉煤灰碎石桩复合地基桩间土的承载力发挥试验分析  

EXPERIMENTAL ANALYSIS OF EFFICIENCY FACTOR OF BEARING CAPACITY FOR SOIL BETWEEN PILES IN CFG PILE COMPOSITE FOUNDATION UNDER HIGH STRESS

作　　者：郅彬[1] 武李和乐 李戈[1] 王永鑫[1] 王番[1] ZHI Bin;WU Lihele;LI Ge;WANG Yongxin;WANG Pan(School of Architecture and Civil Engineering,Xi＇ an University of Science and Technology,Xi＇ an 710054,China)

机构地区：[1]西安科技大学建筑与土木工程学院

出　　处：《工业建筑》2018年第7期106-109,126,共5页Industrial Construction

基　　金：国家自然科学基金项目(41172262)

摘　　要：依据西安黄土地区某工程的单桩复合地基静荷载试验结果,对水泥粉煤灰碎石（CFG）桩复合地基的承载性状及桩土的受力情况进行分析,发现在高应力水平下,桩土应力比随荷载增大而增大,到后期时增长幅度变小,桩间土承载力发挥较低,桩顶将承受约96%的绝大部分荷载,复合地基承载性状与单桩相似,然后根据试验数据反分析出桩间土承载力发挥系数β随着荷载的增大近似呈线性增加,高应力情况下β相较JGJ 79—2012《建筑地基处理技术规范》取值偏低,计算复合地基承载力时桩间土承载力发挥系数β不宜盲目按JGJ 79—2012建议值取值。由数值模拟得出,在设计类似工程时可考虑垫层厚度选用300 mm,β值取0.6,为西安地区CFG桩复合地基设计提供参考。Based on a project in Xi ＇an loess area,the static load test of single pile composite foundation was completed,the bearing behavior of CFG pile composite foundation and the bearing condition of pile and soil were analyzed based on test results. The results showed that the pile-soil stress ratio increased with the increase of loads and finally increased slightly under high stress,the efficiency of bearing capacity for soil between piles was lower and the top of pile bore 96% load,the bearing characteristic of the composite foundation was similar to the single pile.According to the back analysis of the test data,efficiency factor bearing capacity β for soil between piles was obtained,which increased approximate linear with the loads, the values of β were lower compared with the recommended values in Technical Code for Ground Treatment of Building（ JGJ 79—2012） under high stress. When pre-calculating the bearing capacity of CFG pile composite foundation based on the code,the recommended values βin the code should not be taken blindly. Through the numerical simulation,it could be concluded that the cushion thickness should be 300 mm and the value of β should be 0. 6,it could provide reference for CFG pile composite foundation design in Xi＇an.

关 键 词：水泥粉煤灰碎石桩复合地基 承载性状 静荷载试验 桩土应力比 桩间土承载力发挥系数 

分 类 号：TU473.1[建筑科学—结构工程]