软土地区大型基坑平行分区研究  

STUDY OF LARGE-SCALE EXCAVATION PARALLEL ZONED IN SOFT CLAY

作　　者：黄沛[1] 刘青[2] 石海丽 张亚国[1] HUANG Pei;LIU Qing;SHI Haili;ZHANG Yaguo(School of Civil Engineering,Chang an University,Xi’an 710061,China;CCCC First Highway Consultants Co.,Ltd.,Xi’an 710068,China;China United Northwest Institute for Engineering Design and Research Co.,Ltd.,Xi’an 710077,China)

机构地区：[1]长安大学建筑工程学院,西安710061 [2]中交第一公路勘察设计研究院有限公司,西安710068 [3]中联西北工程设计研究院有限公司,西安710077

出　　处：《工程地质学报》2024年第5期1850-1859,共10页Journal of Engineering Geology

基　　金：国家自然科学基金项目(资助号:51608042);中央高校基本科研业务费专项资金项目(资助号:300102281203,300102281206)。

摘　　要：为了给软土地区大型基坑平行分区的设计和施工提供理论依据,结合软土地区大型基坑平行分区典型分区参数,建立数值计算模型,对分区后邻近被保护建/构筑物一侧围护墙的水平位移、地表沉降以及坑外土体沉降和水平位移进行分析,在此基础上研究大型基坑平行分区控制变形的机理。研究结果表明:分区后的围护墙顶部的水平位移比未分区的稍大,围护墙最大水平位移深度与未分区相近,但围护墙最大水平位移比未分区时减小31.1%;分区后最大地表沉降位置比未分区时更接近基坑,最大地表沉降比未分区时减小35.1%;围护墙的水平位移、地表沉降和坑外土体变形主要由邻近狭窄基坑开挖引起;分区后土体内部沉降、水平位移和坑底隆起影响深度均小于未分区时的值。分区后,在远处大面积基坑开挖过程中,基坑外侧围护墙凭借其较大的刚度,对土体变形具有较强的遮拦效应;近处小面积基坑开挖时,可以充分利用基坑宽度较小时开挖引起的变形也较小的规律;大面积基坑分区开挖符合基坑变形时空效应理论的要求。平行分区可以充分利用基坑外侧围护墙对变形的遮拦、基坑宽度对基坑变形的影响以及基坑变形的时空效应,从而使得平行于分隔墙一侧的围护结构变形和地表沉降大幅减小。In order to provide theoretical basis for the design and construction of large excavation parallel zoned in soft clay,numerical models were established based on the typical parameters of parallel zoned.The horizontal displacement of retaining wall,the surface settlement,the internal settlement and horizontal displacement of the soil outside the excavation are analyzed.Moreover,the mechanism of deformation controlling during parallel zoned of large-scale excavation was studied.After zoned,the horizontal displacement of the top of retaining wall is slightly larger than that of the non-zoned excavation.The depth of the maximum horizontal displacement is similar to that of non-zoned excavation,but the maximum horizontal displacement of retaining wall is 31.1%less than that of the non-zoned excavation.The position of the maximum surface settlement is closer to excavation than non-zoned excavation,and the maximum surface settlement is reduced by 35.1%than that of non-zoned excavation.The horizontal displacement,surface settlement and soil deformation outside the excavation are mainly caused by the excavation of the adjacent narrow foundation pit.The internal settlement,the horizontal displacement of the soil and unloading impact depth are smaller than those of without zoned.During excavation of the distant large-area excavation,the outer retaining wall has a strong shielding effect on soil deformation by its greater rigidity.When excavating the narrow excavation,the rule that the smaller the excavation width,the smaller the deformations caused by the excavation can be fully utilized.Zoned excavation is consistent with the time-space theory.The parallel zoned can take full advantage of the shielding effect of the outer retaining wall,the excavation width effect on deformations,and the time-space effect.

关 键 词：基坑工程 分区开挖 沉降 软土 变形控制 

分 类 号：TU473[建筑科学—结构工程]