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城市深基坑工程周边环境变形要求非常严格。因基坑开挖引起的土层扰动,可能会造成建筑物及地下管线破坏,甚至引起基坑失稳。为解决其安全性评价这一难题,吸收强度折减法的优点,提出了基于强度折减技术的深基坑周边环境安全系数的计算方法。以深基坑支护结构水平位移值达到设计控制值作为周边环境破坏的临界判据,通过不断搜索折减系数F,将岩土体材料的力学参数按F值折减代入计算模型中,达到临界条件的折减系数即为安全系数Fs。工程实例分析表明,该方法可以客观、有效地评判深基坑施工中周边环境的安全裕度,为城市深基坑施工顺利进行提供参考。
Urban deep foundation pit surrounding environment deformation requirements are very strict. Due to soil disturbance caused by excavation of foundation pit, it may cause damage to buildings and underground pipelines and even cause instability of foundation pit. In order to solve the problem of safety evaluation and absorb the advantages of strength reduction method, a method of calculating the safety factor of surrounding environment of deep foundation pit based on strength reduction technique is proposed. Based on the fact that the horizontal displacement of deep foundation pit support structure reaches the design control value as the critical criterion for the damage of the surrounding environment, by continuously searching for the reduction factor F, the mechanical parameters of the rock mass material are reduced by the F value into the calculation model and reach the critical value The reduction factor of the condition is the safety factor Fs. The engineering example shows that this method can objectively and effectively evaluate the safety margin of the surrounding environment in the construction of deep foundation pit and provide reference for the smooth construction of urban deep foundation pit.