基坑转角处三维空间效应对稳定性影响分析

Study on Influence of 3D Spatial Effect at Foundation Pit Corner on Stability

为了从定量角度深入研究基坑空间形态对基坑稳定性的影响,运用有限差分软件FLAC3D分别建立基坑边坡的阴角和阳角模型。基于点安全系数方法,分别求出开挖后基坑阴角和阳角模型的整体安全系数;通过点安全系数的空间分布规律分析阴(阳)角的空间效应;结合基坑边坡准三维剖面模型的整体安全系数计算结果,对比分析基坑边坡中阴(阳)角对三维稳定性的影响规律。计算结果显示:基坑边坡阴角处三维稳定性提高约5.48%,阳角处降低约7.76%;阴(阳)角地形对基坑边坡的稳定性影响明显,基坑工程中需要调整相应的支护设计,确保基坑施工安全。

In order to study the influence of foundation pit's spatial form on its stability quantitatively,finite element difference software FLAC3D was used to establish the models of internal and external corners of the excavation slope respectively.By means of point safety factor,the overall safety factors of these models after excavation were obtained;then the spatial effect at the internal(external)corner was analyzed according to the spatial distribution law of point safety factor;combined with the calculation result of the overall safety factor of the quasi-three-dimensional profile model of the slope,the influence laws of the internal(external)corner on the 3D stability were compared and analyzed.The result shows that,the 3D stability at the internal corner of foundation pit slope is increased by about 5.48%and that at the external corner is decreased by about 7.76%;the landform at the internal(external)corner has significant influence on the stability of foundation pit slope,and the corresponding supporting design in foundation pit engineering needs to be adjusted in order to ensure the safety of construction.