砂土地层圆形深基坑三维分析与测斜仪测量  

Three-dimensional analysis and inclinometer measurements in deep circular excavation in sand soil

作　　者：HANIFAH Hermil Rizki RAHARDJO Paulus Pramono LIM Aswin HANIFAH Hermil Rizki;RAHARDJO Paulus Pramono;LIM Aswin(Department of Civil Engineering,Parahyangan Catholic University,Bandung 40141,Indonesia)

机构地区：[1]万隆天主教大学土木工程系,印度尼西亚万隆40141

出　　处：《岩土力学》2023年第4期1142-1152,共11页Rock and Soil Mechanics

摘　　要：介绍了铁皮坑开挖中测斜仪监测和三维有限元反分析的结果。所研究的铁皮坑为深度27 m、总直径26 m的圆形深基坑,最终开挖面以上土层以砂土为主。每个开挖阶段采用腰梁加固的咬合桩作为挡土墙对基坑进行支护。采用硬化土模型作为土体本构模型,反分析结果表明,桩墙位移的趋势与测斜仪测量的结果接近,最大位移为5.1mm。案例中胶结土的有效黏聚力c′取决于胶结砂层的厚度,约为50~200kPa。NSPT为标准贯入试验中分离式取样器打入土体30cm的锤击数。模拟结果表明,砂土模量约为1 400NSPT~2 000NSPT(单位:k Pa),而对于胶结砂,其模量为7 000NSPT。还研究了腰梁和外部荷载对咬合桩变形和受力的影响。结果表明,外部荷载对桩墙位移具有主导作用;同时,腰梁对减少桩墙位移没有明显作用。This paper presents the results of the inclinometer monitoring and back analysis using three-dimensional finite elements in the scale pit deep excavations. Scale pit is a deep circular excavation construction with a depth of-27 m and a total diameter of 26 m.The soil layer above from the final excavation is dominated by a sandy soil layer. The retaining wall construction is a secant pile reinforced with waler beams at each excavation stage. The hardening soil model was used as soil constitutive model. The results of the back analysis show that the trend of wall deflection is close to the results of the inclinometer measurements. The maximum deflection that occurs in the wall is 5.1 mm. The effective cohesion c′ of cemented soil in the case is about 50 to 200 kPa, depend on the depth of cemented sand layer. NSPT is a number of blows for a split-barrel sampler to penetrate 30 cm into the soil during Standard Penetration Test. The soil modulus in sand soil as a result of the modeling is equivalent to 1 400 NSPT to 2 000 NSPT(unit: kPa), while for cemented sand, it is equivalent to 7 000 NSPT. This study also investigated the effect of waler beam installation and external loads on the deformations and forces that acting in the secant pile. In this case, the external load has a dominant effect in the result of wall deflections. Meanwhile, the waler beam has no significant effect for reduce the wall deflection.

关 键 词：圆形深基坑 测斜仪 反分析 胶结砂 三维有限元 

分 类 号：TU473[建筑科学—结构工程]