不同地质条件下基坑监测范围探析

Analysis of Monitoring Scope of Foundation Pit under Different Geological Conditions

基坑工程的区域性非常强,不同地质条件下基坑变形不相同。为更好了解不同地质条件下相适应的基坑监测范围,文章结合国内外学者在不同地区的研究结论,总结了不同地质条件下基坑的监测范围。通过总结得出:(1)土质条件下最适合的监测范围是在基坑开挖深度的4倍范围内,其中主影响区域为在距离开挖深度2倍范围内沉降较大的区域;次要影响区域为在距离基坑开挖深度2~4倍范围内沉降较小的区域。(2)软土条件下监测范围主要影响区为0~2倍开挖深度,次要影响区在开挖深度2~3.5倍范围内,弱影响区为3.5倍开挖深度之外的区域。与土质条件下的监测范围不同,软土的沉降影响范围较深,所以对深厚软土监测范围可视情况适当扩大。花岗岩残积土条件下影响范围大致在开挖深度0~2倍范围内。(3)岩质和土岩组合条件下基坑监测范围与土质条件下差别较大,其主要影响区在开挖深度0.5倍范围内,次要影响区域为0.5~1.5倍开挖深度。

The regionality of the foundation pit project is very strong,and the deformation of the foundation pit is different under different geological conditions.In order to better understand the monitoring range of foundation pits adapted to different geological conditions,summarizes the monitoring scope of foundation pits under different geological conditions in combination with the research of domestic and foreign scholars' conclusion in different regions.It is concluded that:(1) The most suitable monitoring range under soil conditions is within4 times the excavation depth of the foundation pit,of which the main influence area is the area with large settlement within 2 times of excavation depth;The secondary area of influence is the area with less settlement within the range of 2~4 times from the depth of foundation pit excavation.(2) Under soft soil conditions,the main influence zone is 0~2 times of excavation depth,the secondary influence zone is 2~3.5 times of excavation depth,and the weak influence zone is the area outside 3.5 times of excavation depth.Different from the monitoring range under soil conditions,the settlement influence range of soft soil is deeper,so the monitoring range of deep soft soil can be appropriately expanded according to the situation.And the influence range under granite residual soil conditions is roughly 0~2 times of excavation depth.(3) The monitoring range of foundation pit under the combined conditions of earth-rock combination and rock is quite different from that under soil conditions.The main influence area is within 0.5 times of excavation depth,and the secondary influence area is 0.5~1.5times of excavation depth.