排桩冻结法深基坑排桩监测水平位移校正模型

Rectification model for horizontal displacement monitoring of piles to support deep foundation pits with frozen ground

对润扬大桥南锚碇排桩冻结法深基坑,通过孔内测斜对排桩水平位移进行监测,监测过程中发现由于冻结和孔底端部位移造成排桩测斜数据有较大误差,必须建立有效的位移校正方法对排桩测斜数据进行校正。数据分析表明,通过压顶梁水平位移不能校正排桩水平位移测斜数据误差,而利用支撑位置位移校正排桩测斜水平位移误差是可行的。通过第一道支撑位置支撑轴力和温度参数对排桩水平位移进行校正,得到排桩水平位移校正模型。利用已有的监测数据,对排桩水平位移校正模型从两方面进行了验证,结果表明,校正模型的建立为基坑反演分析和基坑稳定性预测预报提供了较准确的排桩水平位移监测数据。

The pile-supported deep foundation pits with frozen soil were adopted at south anchorage of Runyang Bridge, and the horizontal displacement of piles was monitored by in-hole inclinometers. Owing to the fact that the soil freezing and the displacement at the bottom of the holes result in large error in measured data, it is necessary to develop an effective method to rectify the measured data from inclinometers. Numerical analysis shows that the disphcement of the support position can be used for rectification of the measured data. Based on rectification of the measured data of horizontal displacement of piles with the support axial, force at the fLrSt support position and temperature parameter, a horizontal displacement rectification model for piles is obtained, and the model is verified with the data having been obtained. The present model provides accurate monitoring data of horizontal displacement of pries for back analysis and prediction of stability of foundation pits.