基坑工程环境沉降测量平差方法研究

Study of Error Adjustment Methods for Settlement Survey Caused by Pit Construction

通过对三个工程实例中70个点位分别采用简单平差法和最小二乘法(间接平差法)所得高程的比较研究,发现两者不符值在闭合环线上表现为"首尾小,中间大";不符值的平均值远小于"二等"变形测量中变形点高程中误差限值,最大不符值也仅有"一级"基坑环境沉降警戒值的1.2%.因此认为:基坑工程环境沉降监测可以采用简单平差法进行成果处理.

The study is carried on 70 nodes belonging to three practical leveling networks, and the heights of each node determined by the Simplified Error Adjustment and the Least Squares Method are compared. The results show that the height difference on initial and termination nodes in the leveling loops is smaller than the ones on the mid-loop nodes. However, the difference is tiny when it is compared with the Error Limitation stipulated in the National Code for Deformation Survey, and the maximum difference only accounts for 1.2% of the Alarming Limitation in Pit Construction Code. Thus, that the Simplified Error Adjustment may be used for settlement survey caused by pit construction is suggested.