抗液化排水刚性桩沉桩过程的土压力响应

抗液化排水刚性桩是一种将刚性桩与竖向排水体相结合的新桩型。基于某建筑桩基工程，开展了抗液化排水刚性桩和不含排水体的普通刚性桩的沉桩对比现场试验，采用了动态土压力传感器实时监测沉桩过程中桩周土体内产生的土压力响应，对比了排水桩与普通桩沉桩对桩周土体水平方向应力及有效应力影响的差异。试验结果表明：抗液化排水刚性桩能够有效减小沉桩过程对桩周深部可液化土体的扰动，在桩身近侧（距桩心0.6 m）深部埋深（-15 m）位置，排水桩的水平土压力响应峰值仅为普通桩的1/4；排水桩能够有效降低沉桩对可液化土层有效应力的影响，使桩周土体更加稳定；在单次沉桩过程中，对于浅部埋深（-5 m），排水桩对桩周土压力峰值的影响作用较小，对于存在可液化土层的深部埋深（-10、-15 m），排水桩对土压力峰值的有效影响半径可达4倍桩径。现场试验数据为抗液化排水刚性桩的桩间距选择提供了有力的设计参考依据。

Soil pressures of the anti-liquefaction rigid-drainage pile during pile driving

The anti-liquefaction-rigid-drainage pile is a new pile type combining the bearing capacity of rigid pile and the drain ability of gravel pile. In a pile foundation project, pile driving field tests of the rigid-drainage pile were carried out. The horizontal and vertical soil pressures around drainage piles and ordinary piles were recorded in different locations and depths using dynamic sensors during field tests. According to these test results, rigid-drainage pile can reduce the disturbance of soil pressures during pile driving. At the location 0.6 m far from the pile center in the depth -15 m, the peak horizontal soil pressure around the rigid-drainage pile is a quarter of the ordinary pile’s. The rigid-drainage pile can reduce the impact of pile driving on the effective stress in soil, which makes the liquefiable soil around rigid-drainage piles more stable. In the depth of -5 m, the effect of rigid-drainage piles on soil pressure is not obvious. In deep depths (-10, -15 m), the effective influence radius of rigid-drainage piles is about 4 times as large as the pile diameter. The data of piles tests provide other engineers with reliable evidences.