深厚软土地基上振动沉拔钢护筒对周围土体扰动影响的研究

Disturbance effect on soft clay foundation due to steel tube driving by use of shaking method

根据现场测试结果研究深厚软土地基上振动沉拔钢护筒对周围软土的扰动影响。测试结果表明:护筒在振动沉拔过程中对土体的挤压位移(包括地表沉降、地表位移和深层水平位移)不大。随着钢护筒入土深度的增加,土体局部范围内产生较大的挤压应力和孔隙水压力,但挤压效应的影响主要集中在距离钢护筒中心半径为1.5m的范围内。同时,产生深层水平位移最大值的位置随着钢护筒的入土深度增加而不断下移。

The disturbance effect on a very deep soft clay foundation due to steel tube driving was studied by use of in-situ tests It was shown that the extruding displacement （i.e., ground surface settlement, ground surface displacement, and horizontal displacement of soil layer） caused by driving and drawing of a steel tube was not great. Extruding stress and pore pressure generated by driving and drawing of the tube in a local region surrounding the pile increased obviously with the increase of the driving depth of the steel tube; however, the extruding effect was mainly limited within a radial distance of about 1.5 m. In the meantime, the location of the maximum horizontal displacement of soil layer was also moving downward. Moreover, the maximum values of horizontal displacement were smaller than 5 mm when the radial distance was greater than 1.5 m.