邻近超载状态下软土深基坑变形时间特性研究

福建江夏学院,福州 350108

超载,软土,深基坑,数值模拟,时间特性

Study on time characteristics of soft soil deep foundation pit deformation under the condition of overload
ZHANG Fei,WANG Yan,LI Zhi-yuan

ZHANG Fei,WANG Yan,LI Zhi-yuanFujian Jiangxia college,Fuzhou 350108,China

overload,soft soil,deep foundation pit,numerical simulation,time characteristics

备注

邻近超载对软土深基坑变形影响显著,同时软土地区基坑工程施工具有明显的时间效应,而经典弹性及弹塑性模型无法反映这一点.通过建立考虑土体蠕变-固结耦合效应的有限元模型,对不同超载值引起的深基坑工程变形特性进行了分析,并与实测值对比验证.结果表明,超载作用会减少因开挖卸载而在周边土体中产生的负超静孔隙水压力,坑外土体主要表现为流变效应,土体固结效应几乎可忽略,而坑内土体则出现流变-固结耦合效应.超载作用对地下连续墙水平位移影响显著,超载值越大,地下连续墙水平位移越大.邻近基坑超载加大了墙后地表沉降最大值,超载作用使墙后地表沉降最大值作用位置更加靠近挡墙.

Adjacent overload has a significant effect on the deformation of deep foundation pits in soft soil areas.At the same time,the construction of foundation pits in soft soil areas has obvious time effects,while the classical elastic and elastoplastic models can not reflect this.By establishing a finite element model considering the creep-consolidation coupling effect of soil,the deformation characteristics of deep foundation pit caused by different overload sizes are analyzed and verified by comparison with measured data.The results show that the overloading will reduce the negative excess pore water pressure generated in the surrounding soil due to excavation and unloading.The soil outside the pit is mainly rheological,and the consolidation effect of the soil is almost negligible,while the soil in the pit shows the coupling effect of rheology and consolidation.The effect of overloading on the horizontal displacement of the underground continuous wall is significant.The larger the overload value,the larger the horizontal displacement of the underground continuous wall.The near-overload of the foundation pit increases the maximum settlement of the ground surface behind the wall.The overload action causes the maximum surface settlement of the wall behind the wall to be closer to the retaining wall.