水泥搅拌桩复合地基垫层效应研究  

Study on Cushion Effect of Cement-Mixing-Pile Composite Foundation

作　　者：王啟铜 宋神友 陈伟乐 夏丰勇 陈卓杰 WANG Qitong;SONG Shenyou;CHEN Weile;XIA Fengyong;CHEN Zhuojie(Shenzhen-Zhongshan Link Management Center,Guangzhou 510600,China;Guangdong Highway Construction Co.,Ltd.,Guangzhou 510600,China;Zhejiang University,Hangzhou 310058,China)

机构地区：[1]深中通道管理中心,广州510600 [2]广东省公路建设有限公司,广州510600 [3]浙江大学,杭州310058

出　　处：《工业建筑》2023年第12期211-215,共5页Industrial Construction

摘　　要：深中通道为国内首次大规模采用深层水泥搅拌桩(DCM桩)处理沉管隧道地基的超级工程。由于碎石垫层+块石振密垫层+DCM桩复合地基的沉降变形规律尚不明确,为研究垫层效应对水泥搅拌桩复合地基沉降的影响规律,在现场荷载板试验的基础上,应用数值模拟的方法分析碎石垫层厚度、模量以及块石振密厚度对复合地基桩顶沉降和总沉降的影响。研究结果表明:在刚性基础下设置柔性垫层能使基础由“刚”变“柔”,垫层能调节桩、土所承担的荷载,使桩体承担的荷载变小,土体承担的荷载荷载变大,以致桩顶沉降减小,复合地基总沉降增大。随着垫层刚度的减小(厚度增大或者模量变小),其调节桩土所承担荷载的效果并不会一直变大,在复合地基承载力不变的同时,总沉降继续增大。从提高复合地基承载力和控制沉降考虑,结合工程实际情况,建议碎石垫层的厚度取0.4~0.8 m,模量取10~20 MPa,块石振密的厚度取0.7~1.1 m。Shenzhen-Zhongshan Link was a super infrastructure project in China,in which the deep cement-mixed piles(DCM piles)were first widely used to improved the foundation of the immersed tunnel.Due to a lack of knowledge about settlement laws of composite foundation composed of the gravel cushion,the block-stone-vibrated cushion and DCM plies,to study the effect of cushion on settlement of composite foundation of DCM plies,based on the static load test on site,the influence of thickness,moduli of the gravel cushion and the block-stone-vibrated thickness on the settlement of pile tops and the total settlement of composite foundation were analyzed by numerical simulations.The results indicated that the flexible cushion under the rigid foundation could make the foundation flexible from rigid,and the cushion could adjust the loads shared by piles and soil,so that loads shared by piles became smaller and loads borne by soil were larger,which leaded to the settlement of pile tops decreased and the total settlement of composite foundation increased.With the decrease of cushion stiffness(increasing thicknesses or decreasing moduli),the adjusting effect of loads shared by piles and soil would not maintain continuous growth.With the increase of total settlement,the bearing capacity of composite foundation almost remained stable.To improve the bearing capacity of composite foundation and control settlement,combined with the actual project,it was suggested that the thickness of the gravel cushion should range from 0.4 to 0.8 m,the modulus should range from 10 to 20 MPa,and the block-stone-vibrated thickness should range from 0.7 to 1.1 m.

关 键 词：沉管隧道 复合地基 垫层效应 沉降 

分 类 号：U459.5[建筑科学—桥梁与隧道工程] U455.4[交通运输工程—道路与铁道工程]