顺层岩体边坡开挖过程模型试验

Model experiment in excavation of rock bedding slope

边坡开挖引起的变形及应力调整规律是边坡安全监控的科学依据,模型试验是揭示公路高切坡变形与应力变化规律的重要途径,针对巫山至巫溪公路k88段岩体高边坡,通过相似模型试验探讨边坡开挖过程中坡内位移和应力变化规律。通过相似材料试验获得了模型试验相似材料,配合比"硼砂:水:砂:水泥:石膏"为0.01:1:7.705:0.384:0.900,构建了几何相似比1:30的物理试验模型,提出了与实际工程一致的边坡3次开挖工况。试验结果表明,开挖过程中高切坡位移峰值突增现象显著,达到稳定状态的时间4d左右,而应力则成波动衰减状态,10d以后仍然存在衰减趋势;基于开挖过程中边坡变形和应力的不一致性及应力调整的持续性变化规律,提出了岩质边坡以三维应力监测为主、位移监测为辅的边坡监测优化方案。

The variation principle of deformation and stress triggered by excavation of slope often provide the scientific basis for safety monitoring of slope.Model experiment is an important way of displaying evolution of displacement and stress of high-cutting slope along highway.Taking K88＋725 High-cuting Slope that locates in second-grade highway from Chongqing Wushan County to Wuxi County as the prototype,this paper approaches evolution of displacement and stress of slope excavation from similarity model experiment,and obtains Similarity material proportion is that borax： water： sand： cement： plaster is 0.01：1：7.705：0.384：0.900.Using physical model of 1：30 geometry,is divided the excavation of the model into 3 stages according to the actual construction process.The results indicate that the displacement peak is rising suddenly and it will remains steady after 4 days;but stress displays weakening fluctuatly;it will sustain weakening after 10 days.Based on difference of evolution of displacement and stress and continue of stress of slope excavation,the proposal that 3D stresses is principal monitoring and displacement monitoring is minor,is put forward.