桩-网复合路基变形机理的数值分析

基于桩-网复合地基桩-网-土体系作用机理的复杂性,理论研究落后于工程实践等现状,对桩-网复合路基变形机理理论进行了分析,运用有限元数值模拟的方法,对一种新型软土地基处理的路基的沉降、侧向位移、差异沉降进行了数值分析研究。结果表明:(1)在垫层与填土间加入土工格栅后,能减少路基顶面及底面的沉降,但能够更明显地减少路基顶面及底面的差异沉降和坡脚侧向位移;(2)桩间土强度的增加对于路基底面最大差异沉降的影响要比路基顶面要大,路基顶面最大差异沉降的增加大致与桩间距的增加呈正比关系;(3)路堤底面的沉降量出现谷值点是由于桩体作用所致,峰值点是由于土拱效应所致;(4)较大的土工格栅拉伸模量对于减小路基顶面沉降的效果是不明显的,合适的土工格栅拉伸模量能够减小经济投入。

Numerical Analysis on Deformation Mechanism of Pile-geonet Composite Foundation

Based on the complexity of the action mechanism of pile-net-soil system,pile-geonet composite foundation deformation mechanism was analyzed.Then the lateral displacement and differential settlement of the pile-geonet composite foundation as a new soft soil foundation reinforcement was conducted by finite element numerical simulation method.The obtained results show that(1) adding geogrid material between the cushion and earth-filling can reduce the settlements of surface and bottom of subgrade and obviously reduce the differential settlements on surface and bottom of subgrade and lateral displacement of the slope toe;(2) the impact of increment of soil strength between piles on differential settlement on bottom of subgrade is larger than on surface of subgrade,the increase of maximum differential settlement on the top of subgrade is proportional to the increase of pile spacing;(3) the valley point of settlement of the bottom of subgrade is caused by the role of pile,the peak value is caused by arching effects;(4) the larger tensile modulus of geogrid for reducing the effect of settlement on the surface of subgrade is not obvious,so an appropriate tensile modulus of the geogrid material can reduce economic input.