软土地区超深沉井抗隆起计算分析

摘要:

:随着城市土地资源越来越稀缺，沉井在城市地下空间开发中应用也越来越广泛，沉井的深度和尺寸也随之加深、加大。目前规范对沉井设计未有抗突涌破坏的验算，施工单位理论水平认知相对较低，沉井下沉时突涌破坏案例也时有发生。本文结合宁波软土地区某沉井破坏案例，参照基坑工程目前研究成果，以太沙基极限承载力假定为基础，考虑沉井外侧土体抗力，尝试对沉井抗隆起计算进行分析，并采用有限元软件MIDAS GTS对工程案例进行模拟分析，通过变形趋势对沉井抗隆起计算公式进行佐证，通过不同安全系数、不同平面尺寸对沉井的坑内外土体变形趋势分析结果，为宁波等软土地区其他超深沉井提供了有益的参考。

Abstract:

With the scarcity of urban land resources, the application of caissons in the development of urban underground space is more and more extensive, and the depth and size of caissons are also deepened and enlarged. At present, there is no checking calculation of anti-surge damage in the design of caisson in the code, and the theoretical level of the construction unit is relatively low, and the case of surge damage sometimes occurs when the caisson sinks. In this paper, combined with a caisson failure case in ningbo soft soil area, referring to the current research results of foundation pit engineering, based on the assumption of ultimate bearing capacity of ether sand foundation, considering the resistance of soil outside the caisson, the author tries to analyze the calculation of anti-uplift of the caisson, and uses the finite element software MIDAS GTS to simulate the engineering case. The deformation trend is used to prove the anti-uplift calculation formula of the caisson, and the deformation trend of soil in and out of the caisson with different safety factors and different plane sizes is analyzed, which provides a useful reference for other ultra-deep Wells in ningbo and other soft soil areas.