加筋风砂土地基扩展基础的承压性能

PRESSURE-BEARING CAPACITY OF SPREAD FOUNDATION WITH REINFORCED AEOLIAN SAND

进行了下压荷载作用下加筋风砂土地基扩展基础的承载试验,研究了土工格栅及风砂土的剪切与拉拔摩擦特性,进行了14种不同加筋条件下的模型试验,加筋后下压承载力高于未加筋承载力的11.0%～453.0%。相同埋深时,长条形闭口箱型和双层土工格栅的承载力较高,加筋后的抗位移性能增强。加筋风砂土的承载力是由土体的压缩和抗剪能力、格栅与土的相互摩擦、格栅对土体的约束作用产生的。建立了加筋风砂土地基扩展基础承受下压荷载的理论计算公式,计算值与实测值基本吻合。提出了加强风砂土承压性能的有效方法为铺设长条形闭口箱型土工格栅和双层土工格栅。

Behavior of spread foundation on aeolian sand with geo-grids subjected to pressure force is studied with model tests. The properties of direct shear friction and pull-out friction actions are studied. Fourteen types of geo-grid reinforced aeolian sand are selected in the model tests to show that the pressure-bearing capacity of geo-grid reinforced aeolian sand is 11.0%-453.0% higher than that of the unreinforced. The pressure-bearing capacities of rectangle box geo-grid and two layers of geo-grid are higher than those with other types of geo-grids for the same embedment, and the anti-displacement property is improved. It is shown that the mechanism of pressure-bearing capacity is due to the compression of sand, shearing resistance of sand, the mutual frictional action, and restrain action between geo-grids and soils. The formula for calculating pressure-bearing capacity of spread foundations with reinforced aeolian sand is derived and the calculated results agree well with those measured. The rectangle box geo-grid and two layers of geo-grid are shown to be effective to reinforce the aeolian foundation.