摘要
在总结现有水下隧道模袋砂围堰常见断面类型的基础上,针对软土地基模袋砂组合围堰断面尺寸大、阻水比高的问题,以广州某典型软土地基沉管隧道接口段围堰工程为研究背景,提出了低阻水比的模袋砂+钢管桩组合围堰方案。同时,分析了组合围堰中钢管桩的作用机制,探讨了围堰的受力特性,并研究了其对模袋充填厚度、模袋弹性模量和充填砂内摩擦角等参数的敏感性。分析结果表明:1)低阻水比组合围堰方案具有合理性,相较于常规方案,该方案中外侧围堰沉降显著增大,但其对模袋内力的影响较小,整体稳定性良好;2)围堰顶部沉降值和模袋拉力值均随模袋充填厚度的增加而增大;3)模袋弹性模量越大,围堰顶部沉降值越小,但模袋拉力值越大;4)围堰顶部沉降和模袋拉力与充填砂内摩擦角之间存在反向非线性关系。因此建议软土地基上的模袋充填厚度控制在0.5~0.7 m范围内,充填砂内摩擦角不小于28°,并可通过在底部铺设高强土工格栅来增强对围堰顶部沉降及其稳定性的控制。
On the basis of summarizing the common section types of the existing underwater tunnel mold bag sand cofferdam,aiming at the problems of large section size and high water resistance ratio of mold bag sand combined cofferdam on soft soil foundation,the cofferdam engineering at the interface section of a typical immersed tube tunnel on soft soil foundation in Guangzhou is taken as the background,a combined scheme of mold bag sand and steel pipe pile with low water resistance ratio of was proposed.At the same time,the mechanism of the steel pipe pile was analyzed,the mechanical characteristics were discussed,as well as its sensitivity to factors such as filling thickness of mold bag,elastic modulus of mold bag and internal friction angle of filling sand.The results of analysis indicate that:1)The combined cofferdam scheme with low water resistance ratio is reasonable.Compared with the conventional plan,the settlement of the outer cofferdam has significantly increased in this plan.But the influence on the internal force of the mold bag is smaller and the overall stability is good;2)Both the settlement value at the top of the cofferdam and the tension value of the mold bag increase with the increase of the filling thickness of the mold bag;3)The larger the elastic modulus of mold bag,the smaller the settlement value at the top of the cofferdam,but the larger the tension value of the mold bag;4)There is an inverse nonlinear relationship between the settlement at the top of the cofferdam,the tension of the mold bag,and the internal friction angle of the filled sand.It is recommended to control the filling thickness of the mold bag within the range of 0.5~0.7 m on soft soil foundation,with a friction angle of no less than 28°inside the filled sand,and to enhance the control of settlement and stability at the top of the cofferdam by laying high-strength geogrid at the bottom.
作者
黄雪阳
刘力英
杨春山
Huang Xueyang;Liu Liying;Yang Chunshan(Guangzhou Municipal Engineering Design&Research Institute Co.,Ltd.,Guangzhou 510060,China)
出处
《市政技术》
2024年第7期79-86,238,共9页
Journal of Municipal Technology
关键词
软土地基
阻水比
模袋砂
钢管桩
组合围堰
力学特性
数值模拟
soft soil foundation
water resistance ratio
mold bag sand
steel pipe piles
combination cofferdam
mechanical properties
numerical simulation
