摘要
为分析大气环境下膨胀土高边坡组合式支挡结构的支护响应,对南昆铁路1个膨胀土高边坡多级组合式支挡结构(框架梁锚杆(锚索)+抗滑桩组合式支挡结构)中的土体湿度、土压力、桩身弯矩、坡面位移进行现场监测,分析大气环境下支挡结构的力学演变特征。研究结果表明:监测期间,土体经历了干湿循环作用,引起土体胀缩变形;抗滑桩后土压力走势与土体湿度变化趋势基本一致,且桩后土压力介于主动土压力与静止土压力之间;框架梁后土压力与锚索拉力均自上而下增大,有必要加强边坡底部防护;抗滑桩弯矩增量沿深度呈反C形分布特征,其最大值位于桩身前嵌固段与自由段的分界线附近,该位置为桩身受力状态的最不利处;坡面位移与支护结构内力变化范围幅度不大,表明框架梁锚杆(锚索)+抗滑桩组合式支挡结构可用于膨胀土高边坡防治。
To analyze supporting response of the combined supporting structure of expansive high slope under ambient atmospheric environment,a field monitoring of soil moisture,earth pressure,pile bending moment and slope displacement in the multi-stage combined supporting structure(i.e.,a combined supporting structure composed of frame beam anchor rods(anchor cables)+anti-slide piles)of an expansive soil high slope on the Nanning−Kunming railway was performed.The mechanical evolution characteristics of the supporting structure during service process were analyzed.The results show that the expansive soil experiences wetting-drying cycles during the monitoring period,which causes the soil to undergo swelling-shrinkage deformation.The variation trend of the earth pressure behind the anti-slide pile is consistent with the change trend of soil moisture and its value is between the active earth pressure and the static earth pressure.The earth pressure behind frame beam and anchor cable tension increases gradually from the upper part to the lower part of the slope.Therefore,it is necessary to strengthen the protection of the bottom of the slope.The bending moment growth of the anti-slide pile has a reversed C-shaped distribution characteristic along the depth and its maximum value is located near the boundary between the front embedded section and the free section of the pile,which is the most unfavorable position of the mechanical state of the pile body.The slope displacement and the internal force of the supporting structure vary in a small range,indicating that the frame beam anchor rod(anchor cable)+anti-slide pile combined supporting structure is suitable for the prevention and treatment of expansive soil high slopes.
作者
杨果林
李琪焕
段君义
罗桂军
肖洪波
杨天尧
YANG Guolin;LI Qihuan;DUAN Junyi;LUO Guijun;XIAO Hongbo;YANG Tianyao(School of Civil Engineering,Central South University,Changsha 410075,China;CCFEB Civil Engineering Co.Ltd.,410004,China)
出处
《中南大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2022年第1期171-180,共10页
Journal of Central South University:Science and Technology
基金
国家重点研发计划项目(2019YFC1509800)
国家自然科学基金资助项目(51678571,51778641)。
关键词
膨胀土
多级支挡结构
锚索框架梁
土压力
expansive soil
combined supporting structure
anchor cable frame beam
earth pressure
