循环荷载下粉煤灰群桩复合地基承载性能试验研究

Experimental Study on Bearing Capacity of Fly Ash Pile Group Composite Foundation Under Cyclic Load

在不同的循环荷载比和循环次数下进行循环荷载室内模型试验,从桩顶累积沉降、桩身应力、桩间粉煤灰应力和桩土应力比等方面分析循环次数和循环荷载比等因素对粉煤灰复合地基承载特性的影响。在循环荷载作用下,桩顶累积沉降与循环荷载比呈非线性相关关系,桩顶累积沉降曲线主要分为稳定型和发展型等2种变化形态;随着循环次数的增加,桩身应力和桩间粉煤灰应力均呈现先增大后稳定的趋势;当循环次数超过临界次数时,桩土应力比的减小速率将出现收敛;循环荷载比的增大会导致土拱效应发挥不稳定。

Based on the laboratory model test conducted under different cyclic load ratios and cycles,the effects of cyclic load on the bearing characteristics of fly ash pile group composite foundation are analyzed from the aspects of pile top cumulative settlement,pile body stress,inter-pile fly ash stress,pile-soil stress ratio,etc.The results show that there is a non-linear correlation between the cumulative settlement at the top of the pile and cyclic amplitude under cyclic loading.The cumulative settlement curve at the top of the pile can be divided into stable type and developing type.As the number of cycles increases,the stress on the pile body and the stress on the fly ash between piles show a trend of first increasing and then stabilizing;When the number of cycles exceeds the critical number,the decreasing rate of the pile-soil stress ratio will converge;The increase in cyclic amplitude will lead to unstable soil arching effect.