摘要
为进一步研究复合桩加固液化土在地震荷载作用下桩体沉降变形,利用振动台对钢管—碎石桩加固的复合地基模型在不同荷载作用下进行对比试验。施加0 kg、0.5 kg、1.0 kg、1.5 kg、2.0 kg、2.5 kg六组竖向荷载下,对复合桩加固模型振动过程中不同埋深处超静孔隙水压力和地基沉降进行对比分析,揭示钢管—碎石桩复合加固模型超静孔隙水压力、沉降随荷载的变化规律。结果表明:同一竖向荷载下埋深越大孔隙水压力越大,孔隙水压力的峰值也越大;不同竖向荷载下,不仅随着荷载增大超静孔隙水压力峰值变大,而且超静孔隙水压力随荷载增大消散明显加快,说明竖向荷载作用加速了碎石桩排水功能;施加不同荷载,桩体沉降均随振动时间先缓慢增加又急速增大最后趋于平缓,竖向加荷1.0 kg成为突变点;随着碎石桩的排水,孔隙水压力逐渐消散,土体变密,超静孔隙水压力减小,液化土强度增强,桩周土体对桩约束力增强,桩体的沉降量减小。说明荷载作用下钢管—碎石桩加固复合地基对预防土体液化和提高地基承载力效果明显,并得出沉降量随时间变化的曲线方程,为今后复合桩加固液化土地基的应用提供一定参考。
In order to study the settlement of piles in the liquefiable soil reinforced by composited pile under the vertical load due to earthquake, steel-grave piles in the composite foundation model under different loads on the shaking table were analyzed. Under the six groups of vertical loads, 0 kg, 0. 5 kg, 1. 0 kg, 1. 5 kg, 2. 0 kg and 2. 5 kg, the variation of pore water pressure and the set-tlement of the piles in different depths of the soil were obtained and compared. The results show that, under the same vertical load in different depths, the higher the depth is, the larger the pore water pressure will be. Under different vertical loads, the excess pore water pressure peaks, and then it reduces faster along with the increase of load, which indicates that the vertical load acceler-ates the drainage ability of the gravel pile. Under different loads, the piles settle slowly before the excess pore water pressure of the liquefiable soil reaches the peak. With the shaking of the table, the piles sink rapidly after the pore water pressure reaches the peak. The vertical load of 1. 0 kg be-comes a turning point. But with the drainage of the gravel pile, the pore water pressure dissipates＆amp;nbsp;gradually, the soil becomes more compact, super static pore water pressure decreases, liquefiable soil strength enhancement, the friction around the pile increases and the settlement of pile decrea-ses. Therefore, under the vertical load, making use of the steel-gravel pile composite reinforcement can effectively resist soil liquefaction and improve foundation bearing capacity. And the derived set-tlement curve equation provides a reference for the future application of composite pile reinforced liq-uefied foundation.
出处
《广西大学学报（自然科学版）》
CAS
北大核心
2015年第4期963-968,共6页
Journal of Guangxi University（Natural Science Edition）
基金
国家自然科学基金项目(51408393)
太原理工大学研究生创新基金项目(S2014040)
关键词
液化土
复合桩加固
超静孔隙水压力
振动台
沉降
liquefied sand
composite pile reinforcement
excess pore water pressure shaking ta-ble
settlement of pile
