基于HS-Small模型临江深基坑降水变形特性分析  

Analysis of Deformation Characteristics of Deep Foundation Pit Dewatering Closes to the River Based on HS-Small Model

作　　者：黄建华 李瑞 HUANG Jian-hua;LI Rui(School of Civil Engineering,Fujian University of Technology,Fuzhou 350118,China;Key Laboratory of Underground Engineering,Fujian Province University,Fujian University of Technology,Fuzhou 350118,China)

机构地区：[1]福建理工大学土木工程学院,福建福州350118 [2]福建理工大学地下工程福建省高校重点实验室,福建福州350118

出　　处：《水电能源科学》2023年第11期116-120,203,共6页Water Resources and Power

基　　金：国家自然科学基金项目(51678153);福建省自然科学基金项目(2021J011064)。

摘　　要：临江深基坑工程地下水随江水位变化呈现长期水位低、汛期水位高的动态特征,坑内降水导致周围地层渗流场趋于复杂,易引发围护结构破坏、坑底管涌和基坑失稳等工程事故。为此,采用基于HS-Small本构模型对深基坑工程的开挖-降水过程进行模拟,分析了降水影响因素(降水深度、方式、速率和止水帷幕)对周围环境变形的敏感性及其相互之间的关系,并将分析结果与实测结果进行对比验证。结果表明,随临江深基坑土方开挖和降水进行,基坑坡顶、坑外土体和周边建筑物沉降变形逐渐增大,其中降水对基坑变形影响更明显;分次降水能有效降低周围建筑物和地表的沉降变形;降水深度建议控制在底板以下0.5~2.0 m;降水速率对周围环境沉降总量影响相对较小,但对沉降速率影响较大,当降水速率达到最优值时对基坑稳定性控制有益;止水帷幕嵌入深度超过30 m后对控制周围建筑沉降效果不明显。研究结果可为类似临江深基坑降水工程设计施工提供借鉴和参考。The groundwater level in the deep foundation pit project close to the river shows a dynamic characteristic of long-term low water level but high water level during flood season.Foundation pit dewatering leads to the complexity of the seepage field in the surrounding stratum environment,destruction of enclosure structures,accidents include piping and instability at the bottom of the pit.Therefore,this paper simulated the excavation-precipitation process of deep foundation pit project based on the HS-Small constitutive model,analyzed the sensitivity of precipitation influencing factors(precipitation depth,mode,rate and water stop curtain) to the surrounding environment deformation and their relationship.Compared the analysis results with the measured results,it can be found that the settlement of the top of the foundation pit,the soil outside the pit and the surrounding buildings gradually increases,and the dewatering has a more obvious influence on the deformation during the excavation and dewatering of the foundation pit;Fractional precipitation can effectively reduce the settlement deformation of surrounding buildings and ground surface;It is recommended that the dewatering depth of foundation pit should be controlled within 0.5-2.0 m below the bottom plate;The precipitation rate has a relatively small impact on the total settlement of the surrounding environment,but has a great impact on the settlement rate.When the precipitation rate reaches the optimal value,it is beneficial to the stability control of the foundation pit.The embedded depth of water-proof curtain in this project is more than 30 m,which has no obvious effect on controlling the settlement of surrounding buildings.The research results can provide reference for the dewatering design and construction of similar deep foundation pit projects closed to the river.

关 键 词：临江工程 HS-Small本构模型 开挖降水 沉降机理 软土地区 

分 类 号：TU753[建筑科学—建筑技术科学]