首页|长江某大桥高峰岸锚碇基坑边坡应力变形及支护效果数值模拟分析

长江某大桥高峰岸锚碇基坑边坡应力变形及支护效果数值模拟分析

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依据工程地质资料及锚碇基坑支护设计方案,利用ANSYS软件构建长江某大桥锚碇基坑的三维地质概化模型,将模型导入FLAC3D中模拟分析了锚碇基坑开挖支护全过程中的应力、变形及塑性区演变特征.结果表明:基坑开挖过程中,岩体应力集中现象相对较轻,整体以压应力为主,分布较均匀;开挖后基坑的整体变形趋势是向上向临空面回弹变形,底板最大综合位移为14.7 mm,边坡最大变形出现在北侧反倾向边坡,变形值8.65 mm;塑性区体积持续增大,仅在最后一级开挖时有所降低;开挖完成后,基坑北侧的岩体内出现大量塑性区.与单一锚杆支护方案相比,锚杆+锚索支护方案北侧高边坡岩体变形平均减小16.6％,开挖完成后塑性区体积减小8 600 m3,最大分布深度从15 m减小到5 m.锚杆+锚索支护方案不仅较好地抑制北坡变形,而且有效减小岩体内塑性区分布深度,提高岩体稳定性,基坑边坡支护效果更好.
Numerical Simulation Analysis of Stress Deformation and Anchoring Support Effect of Foundation Pit Slope for One Bridge on Gaofeng Bank of Yangtze River
Based on the engineering geological data and the anchoring support scheme for a foundation pit,a three-dimensional geological generalization model was constructed with ANSYS software for the foundation pit of one bridge over the Yangtze River.This model was then imported into FLAC3D to simulate and analyze the stress,deformation and plastic zone evolution characteristics of the foundation pit during the process of excavation and anchoring support.The results show that during the excavation of the foundation pit,the rock mass is generally subjected to well-distributed compression,with less concentrated stress.After excavation,the foundation pit generally appears to have an upward rebound deformation,with the displacement of bottom plate maximally reaching 14.7 mm.It is shown that the counter-trend slope on the north side has the maximum deformation up to 8.65 mm.The volume of the plastic zone continues to increase,and then decreases during the excavation of the last step.After the excavation is completed,a large number of plastic zones appear in the rock mass on the north side of the foundation pit.Compared to the support scheme with only anchor rods,the support with anchor rods together with anchor cables can make the deformation of the rock mass of slope on the north side reduced by 16.6％on average,as well as the volume of plastic zone reduced by about 8 600 m3 and the distribution depth reduced from 15 m to 5 m after excavation is completed.It is concluded that the support scheme with both anchor bolts and anchor cables can not only effectively suppress the deformation of the slope on the north side,but also effectively reduce the distribution depth of plastic zone in the rock mass and improve the stability of rock mass,presenting better support effect for the foundation pit slope.

foundation with anchoring supportcounter-trend slopestressdeformationfoundation pit supportnumerical simulationanchor rod supportanchor cable support

林丽萍、蒋鑫、李军伟、段艳平、梅松华

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湖南城建职业技术学院,湖南湘潭 411100

湖南科技大学,湖南湘潭 411201

湖南省地质地理信息所,湖南长沙 410014

湖南省自然资源调查所,湖南长沙 410014

中国电建集团中南勘测设计研究院有限公司,湖南长沙 410014

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锚碇基坑 反倾向边坡 应力 变形 基坑支护 数值模拟 锚杆支护 锚索支护

湖南省教育厅科学研究项目湖南省自然资源科研(标准)项目湖南建投集团有限公司科技计划项目

23C0528湘自资科20230143DZJGJTK2021-14

2024

10.3969/j.issn.0253-6099.2024.04.031

矿冶工程
长沙矿冶研究院有限责任公司 中国金属学会

矿冶工程

CSTPCD北大核心
影响因子：1.137
ISSN：0253-6099
年,卷(期)：2024.44(4)