泥水盾构开挖面失稳破坏的颗粒流模拟研究

发布时间：2018-02-24 19:47

本文关键词： 砂卵石地层泥水盾构开挖面稳定颗粒流细观参数泥膜数值模拟颗粒流程序　出处：《中国铁道科学》2017年03期 　论文类型：期刊论文

【摘要】：针对北京砂卵石地层大直径泥水盾构隧道开挖面稳定性和地表沉降的问题,采用颗粒流程序PFC2D研究砂卵石地层土体的颗粒流细观参数,从土体颗粒的摩擦系数和接触模量以及泥膜的厚度和黏合强度对开挖面的作用效果进行分析和评价。结果表明:土体的颗粒摩擦系数和接触模量以及泥膜的厚度和黏合强度对开挖面的稳定性有显著影响;土体颗粒的摩擦系数和接触模量越小,开挖面破坏越严重,地层坍塌轮廓越大,地表沉降槽越深;当土体颗粒的摩擦系数增大到2.4、接触模量增大到12×107 N·m~(-1)时,开挖面趋于稳定,地表沉降槽曲线平缓,地表竖向位移较小;泥膜的厚度和黏合强度越小,开挖面挤出变形越显著,越容易引起较大范围的地层变形,从而导致地表塌陷;当泥膜的厚度为20mm且泥膜黏合强度为1 400N·m~(-1)时开挖面稳定。
[Abstract]:In order to solve the problems of stability of excavation surface and surface subsidence of large-diameter mud-water shield tunnel in Beijing sand pebble formation, particle flow program PFC2D was used to study the particle flow meso-parameters of sand and gravel strata. The friction coefficient and contact modulus of soil particles and the thickness and adhesion strength of mud film are analyzed and evaluated to the effect of excavating surface. The results show that the friction coefficient and contact modulus of soil particles and the thickness of mud film are obtained. And the bonding strength has a significant effect on the stability of the excavated surface. The smaller the friction coefficient and contact modulus of soil particles are, the more serious the excavation surface is, the larger the formation collapse profile is and the deeper the surface subsidence trough is. When the friction coefficient of soil particles increases to 2.4 and the contact modulus increases to 12 脳 10 ~ 7 N 路m ~ (-1), the excavated surface tends to be stable. The surface subsidence trough curve is gentle and the vertical displacement is small. The smaller the thickness and adhesive strength of the mud film, the more obvious the extrusion deformation of the excavated surface is, and the more likely it is to cause the formation deformation in a larger range, which will lead to the surface collapse. When the thickness of the mud film is 20 mm and the adhesion strength of the mud film is 1 400 N 路m ~ (-1), the excavated surface is stable.
【作者单位】：北京交通大学城市地下工程教育部重点实验室;
【基金】：中央高校基本科研业务费专项资金资助项目(2016JBM042)
【分类号】：U455.43

【相似文献】