窄长类匝道基坑开挖变形监测数据统计分析*

为研究窄长类基坑开挖过程中基坑变形性状和基坑开挖对近邻的扰动，以上海市某匝道基坑开挖工程为案例，采用统计方法对该基坑围护结构、邻近地表、周边建筑变形监测数据进行分析。结果表明:相较于民建宽大类基坑，窄长类基坑开挖对于围护结构侧向位移、墙后地表沉降、邻近既有建筑倾斜大小的影响更小，而在围护结构最大侧向位移出现的位置上，二者差别不大；对于窄长类基坑，由于其窄边尺寸效应，窄边处所对应的围护结构变形以及地表沉降，相较于长边均呈现出较为明显的减小；在工程实例中，由于基坑宽度更窄，因此其空间效应更为明显。

Statistical analysis on deformation monitoring data in excavation of narrow and long ramp foundation pit

In order to study the deformation behavior of foundation pit and the disturbance to the neighbors during the excavation process of the narrow and long type of foundation pit,taking the excavation project of a ramp foundation pit in Shanghai as a case,the statistical methods were used to analyze the deformation monitoring data of enclosure structure,adjacent ground surface and surrounding building of the foundation pit.The results showed that from the perspective of data statistics,compared with the wide and large type of foundation pit in the civil building,the excavation of the narrow and long type of foundation pit had less impact on the lateral displacement of enclosure structure,the ground surface settlement behind wall,and the inclination of adjacent existing buildings,while there was no significant difference between them in the location of the maximum lateral displacement of enclosure structure.For the narrow and long type of foundation pit,both the deformation of enclosure structure and the ground surface settlement corresponding to the narrow side presented the more obvious reduction compared with the long side due to the narrow side size effect.In this project,due to the narrower width of the foundation pit,its spatial effect was more obvious.