膨胀土路堑边坡柔性加固方法及现场监测  

Flexible Reinforcement Method and Field Monitoring of Expansive Soil Cutting Slope

作　　者：张锐[1,2,3] 凌时光 郑健龙 周豫[1] 王欢 ZHANG Rui;LING Shi-guang;ZHENG Jian-long;ZHOU Yu;WANG Huan(School of Traffic and Transportation Engineering,Changsha University of Science&Technology,Changsha 410114,Hunan,China;National Key Laboratory of Green and Long Life Road Engineering in Extreme Environments,Changsha University of Science&Technology,Changsha 410114,Hunan,China;Engineering Research Center of Catastrophic Prophylaxis and Treatment of Road&Traffic Safety of Ministry of Education,Changsha University of Science&Technology,Changsha 410114,Hunan,China)

机构地区：[1]长沙理工大学交通运输工程学院,湖南长沙410114 [2]长沙理工大学极端环境绿色长寿道路工程全国重点实验室,湖南长沙410114 [3]长沙理工大学道路灾变防治及交通安全教育部工程研究中心,湖南长沙410114

出　　处：《中国公路学报》2024年第6期87-97,共11页China Journal of Highway and Transport

基　　金：国家自然科学基金项目(51978085);湖南省交通运输厅科技进步与创新项目(202208)。

摘　　要：为了提出一种用于新开挖膨胀土路堑边坡加固的方法并揭示其作用机理,设计了一种柔性面层+土钉加固结构,并建立了相应设计方法;依托云南某高速公路弱膨胀土路堑边坡加固工程,进行了加固结构设计计算及现场试验;开展了加固结构的受力及变形监测,探究了加固结构的作用机理。研究结果表明:当柔性面层允许边坡法向发生3.0%的膨胀变形时,所受到的法向膨胀应力可较不允许发生膨胀变形时下降61.1%,设计的柔性加固结构可满足稳定性的要求。一年内,在雨季土钉中部轴力普遍出现增长,在旱季离坡面较近的土钉端头轴力显著减小;土钉轴力沿土钉长度方向总体呈现“中间大,两端小”分布,与锚杆框架梁相比,受力更为均匀;柔性面层网面的最大拉应变均出现在阶段性停雨后,具有明显的滞后性,且远小于材料极限伸长率;坡面土压力变化与高强加筋三维网应变变化规律基本一致,雨季呈波动增长,旱季缓慢回落,坡面土压力增值与计算所得膨胀力接近;随着土体雨季增湿膨胀、旱季干燥收缩,钢缆绳轴力变化呈现出缓慢增长、持续衰减及逐渐稳定3个阶段;3个监测点位中边坡坡顶水平位移最大,为5.4 mm,边坡整体稳定。监测结果综合反映了柔性加固结构“以柔治胀”的作用机理。所得结论可为新开挖膨胀土边坡的加固设计和施工提供参考。To develop a method for reinforcing newly excavated expansive soil slopes and elucidate their working mechanism,a reinforcement structure comprising a flexible facing and soil nails was designed,and the corresponding design methodology was developed.The design calculations and a field test of the reinforcement structure were conducted in conjunction with the slope reinforcement project on a weakly expansive soil cutting slope along a highway in Yunnan Province.The working mechanism of the flexible reinforcement structure for the expansive soil cutting slope was investigated through field monitoring of the stress and deformation of the reinforcement structure.The results indicate that allowing a 3.0%swelling deformation normal to the slope,the normal swelling stress can be reduced by 61.1%compared to the case where no swelling deformation is allowed,and the designed flexible reinforcement structure can meet the stability requirements.Over the one-year monitoring period,there was a general increase in the axial force in the middle of the soil nails during the rainy season and a significant decrease in the axial force at the ends of the soil nails closer to the slope surface during the dry season.The axial force along the length of the soil nails generally showed larger values in the center and smaller values at the two ends.The force was more uniform and sufficient compared to that of the anchor frame beam.The maximum tensile strain of the flexible-facing mesh was observed after the rain stopped,with a significant hysteresis that was much smaller than the ultimate elongation of the material.The change in soil pressure on the slope surface was similar to the change in strain pattern of the high-strength reinforced three-dimensional mesh,with fluctuating growth in the rainy season and gradual decrease in the dry season.The increase in soil pressure on the slope surface was close to the calculated swelling pressure.As the soil swelled in the rainy season and contracted in the dry season,the axial force of the steel ca

关 键 词：路基工程 膨胀土边坡 现场监测 柔性加固 膨胀力 

分 类 号：U416.1[交通运输工程—道路与铁道工程]