基于灰色组合预测的沿海围垦区基坑工程深层土体变形研究与控制

Study and control of deep soil deformation of foundation pit engineering in coastal reclamation area based on grey combination prediction

我国沿海围垦区深基坑工程,受到地下土含水量大、水位高、渗透性差、易变形的影响,对周边建筑环境产生较严重的破坏,其中,深层土体变形是影响其施工的最直观因素。为能实时获得基坑工程深层土体的变形数据,建立了灰色组合预测模型,即采用灰色关联度的方法,选取周边地表沉降、桩顶位移、支撑轴力以及地下水位等监测值作为组合预测模型的自变量,根据不同影响因素对应深层土体变形值的权重关系,应用于沿海围垦区某基坑工程深层土体变形预测模型中,结果表明灰色组合预测模型较GM(1,1)具有较高的预测精度,在5%以内。同时运用Midas GTS有限元模拟工程案例,从支撑刚度角度,计算其最优面积的大小,通过减小桩顶水平变形,控制基坑工程深层土体位移。

The deep foundation pit engineering in the coastal reclamation area of China is affected by the high water content,high water level,poor permeability and easy deformation of underground soil,which causes serious damage to the surrounding building environment.Among them,the deformation of deep soil body is the most intuitive factor affecting its construction.In order to obtain the deformation data of deep soil in foundation pit engineering in real time,we established a grey combination prediction model,that is,the method of grey correlation degree,and selected the monitoring values such as peripheral surface settlement,pile top displacement,support shaft force,and groundwater level as the independent variables of the combination prediction model.According to different influence factors,the weight of deep soil deformation value is applied to the prediction model of deep soil deformation in a foundation pit engineering in the coastal reclamation area.The results show that the gray combination prediction combination model has higher prediction accuracy than GM(1,1),within 5%.At the same time,the Midas GTS finite element simulation project is used to calculate the optimal area from the support stiffness angle.By reducing the horizontal deformation of the pile top,the displacement of the deep soil in the foundation pit is controlled.