高速铁路桩(帽)网和桩筏复合地基模型试验研究

Experimental study on CFG pile-(cap-)-net and pile-raft composite foundations of high speed railway

结合室内模型试验,对桩(帽)桩网复合地基和桩筏复合地基在路堤荷载作用下的沉降、荷载传递规律进行分析,得到3种复合地基的试验结果虽然在数值上存在一定的差距,但均表现出相似的规律。3种复合地基对沉降均有一定的减小作用,且沉降随荷载的增加均近似呈指数增加的趋势,其中,桩筏复合地基沉降最小;桩身应力随深度呈先增加后减小的趋势,最大值出现在桩顶附近的某一深度处;随荷载增加,桩土应力比整体呈线性增加的趋势。在同一荷载水平(如100 kPa)下,桩筏复合地基沉降最小(5.1 mm)、桩顶应力最大(142 kPa)和桩土应力比最大(7.12)时,加固效果更显著。所得结论在一定程度上可为复合地基类型的选择及工程研究提供参考。

Based on the model test,the settlement and load transfer rule of pile-net,pile-cap and pile-raft composite foundations were analyzed.Although serveral differences are found among these composite founda-tions,the overall regularity is similar.All these composite foundations have a certain effect on settlement reduc-ing,and the settlement has an exponential increase as the load increases.Among them,the settlement of pile-raft composite foundation is the minimum one.With the increase of depth,pile body stress increases firstly and then decreases.The maximum value appeared in a certain depth under the top of pile.As the load increases,the stress ratio of pile-soil increases linearly.Under the same load level （such as 100 kPa）,the settlement and pile top stress of pile-raft composite foundation are minimum （5.1 mm,142 kPa）while stress ratio of pile-soil is the maximum（7.12）.So the reinforcement effect of pile-raft composite foundation is more significant. To a certain extent,the conclusions obtained by this paper can provide reference for the study of the composite foundation theory and engineering research.