首页期刊在线 2023年（第26卷）第3期

土岩组合地层长短桩支护结构力学特性研究

张明1王继文2,3周小涵2,3

Mechanical Properties of Long-short Pile Supporting Structure in Soil-rock Combined Strata

ZHANG MingWANG JiwenZHOU Xiaohan

作者信息:

1.1.中铁大桥勘测设计院集团有限公司， 430101，武汉；
2.2.重庆大学土木工程学院， 400045，重庆；
3.3.库区环境地质灾害防治国家地方联合工程研究中心， 400045，重庆
Affiliation:

China Railway Bridge Survey and Design Institute Group Co., Ltd., 430101, Wuhan, China
关键词:

基坑工程;土岩组合地层;长短桩;数值模拟
Key words:

foundation pit engineering;soil-rock combined strata;long-short supporting pile;numerical simulation
DOI:

10.16037/j.1007-869x.2023.03.018
中图分类号/CLCN:

TV551.4+2∶U231.4
栏目/Col:

研究报告

摘要:

土岩组合地层基坑中若采用长短桩的围护形式，涉及长短桩的协同支护效应，其开挖变形规律不易通过理论公式分析，形变机理尚不明确。采用数值模拟和现场监测相结合的方法，研究土岩组合地层深基坑开挖引起长短桩围护结构的变形与受力特性。研究结果表明：在土岩组合基坑中，长短桩围护结构最大侧移点位于土岩分界面附近，且侧移曲线在开挖面以下迅速收敛，与全土质基坑中围护结构侧移呈现较大差异；风化线以上段桩身弯矩近似呈“两端简支分布荷载梁”类型，风化线以下段桩身弯矩曲线反弯点位于开挖面处；长桩数量减少使支护结构嵌固段约束能力降低，桩身弯矩随之增大，但对风化线以下段桩身弯矩影响较大；各开挖阶段短桩弯矩随长桩同步增大，长桩与短桩表现出一定程度的协同工作机理。

Abstracts:

When the long-short pile enclosure form is adopted in soil-rock combined strata foundation pit, with the synergetic working effect of long-short pile involved, it is not easy to analyze excavation deformation law by theoretical formulas, and the deformation mechanism is unclear. The deformation of long-short pile enclosure structure caused by deep foundation pit excavation in soil-rock combined strata and the mechanical characteristics are investigated by numerical simulation and field monitoring. Results show that: in soil-rock combined strata foundation pit, the maximum lateral deflection point is located near the soil-rock interface and the lateral deflection curve converges rapidly below the excavation face, showing great difference compared to the enclosure structure lateral deflection condition in all soil strata foundation pit; the bending moment curve of pile part above the weathering line is similar to that of a ′simply supported beam with distributed load′, and the inflection point of the pile part bending moment curve below the weathering line is always located near the excavation face; the number decline of long piles reduces the restraint capability of the embedded section of supporting structure and increases the pile bending moment, bringing a relatively significant influence on the bending moment of the pile part below the weathering line; the long piles and short piles demonstrate a level of synergetic working mechanism, accounting for the bending moment increase of short pile simultaneously with long piles at each excavation stage.