摘要
为研究低含水率砂层隧道土拱效应下的破坏模式与松动土压力,自制试验装置开展低含水率条件下Trapdoor试验,利用PIV技术得出破坏模式;分析主应力偏转对侧压力系数的影响。基于椭球体理论,考虑松动区内竖向荷载梯形分布形式与表观黏聚力作用,推导不同土拱效应发挥程度下隧道松动土压力计算公式。研究结果表明,表观黏聚力使模型试验最终滑动面呈现椭圆状,与Terzaghi假设的竖直面存在差别;φ为常数时,K值与埋深正相关,随土拱效应发挥程度增大而增大;土拱效应的发挥程度与埋深成正相关,相同埋深下,K随φ增大而减小,利用本文公式计算出K随φ值变化在0.2~0.7之间。算例表明,相同埋深时松动土压力在不同含水率下随土拱效应发挥呈递减趋势,体现出表观黏聚力随土体饱和度变化规律。
To study the failure mode and loose earth pressure of low moisture content sand tunnels under the soil arching effect,firstly,the self-made test device was used to carry out the Trapdoor test under the condition of low moisture content and the failure mode was obtained using PIV technology.At the same time,the influence of principal stress deflection on the lateral pressure coefficient was analyzed.Based on the ellipsoid theory,considering the trapezoidal distribution of the vertical load in the loose zone and the effect of apparent cohesive force,the calculation formulas for the loose earth pressure of the tunnel under different degrees of soil arching effect were derived.The results show that the apparent cohesion results in the elliptical shape of the final sliding surface of the model test,which is different from the vertical surface assumed by Terzaghi.Whenφis a constant,the K value is positively correlated with the buried depth,and increases with the degree of soil arching effect.At the same time,the degree of soil arching effect is positively correlated with the buried depth.Under the same buried depth,K decreases asφincreases.Using the formula in this paper,the change of K with the value ofφis between 0.2 and 0.7.The example shows that the loose earth pressure in the same buried depth shows a decreasing trend with the arching effect of the soil under different water contents,reflecting the change law of apparent cohesion with the saturation of the soil.
作者
崔蓬勃
朱永全
刘勇
安辰亮
CUI Pengbo;ZHU Yongquan;LIU Yong;AN Chenliang(School of Transportation Engineering,Jiangsu Vocational Institute of Architectural Technology,Xuzhou 221116,China;School of Civil Engineering,Shijiazhuang Tiedao University,Shijiazhuang 050043,China;State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures,Shijiazhuang Tiedao University,Shijiazhuang 050043,China)
出处
《铁道学报》
EI
CAS
CSCD
北大核心
2023年第6期131-141,共11页
Journal of the China Railway Society
基金
国家自然科学基金(51778380)
江苏省建设系统科技项目(2020ZD28,2021ZD19)。
关键词
表观黏聚力
破坏模式
松动土压力
土拱效应
侧压力系数
apparent cohesion
failure mode
loose earth pressure
soil arch effect
lateral pressure coefficient
