耐久性弱化边坡模型试验及DIC位移测试研究

Model Test of Durability Weakened Slopes on Displacement Measuring Using the DIC Technology

边坡岩土与支护结构长期耐久性能弱化对边坡变形及安全稳定性产生影响,开展定量化研究以指导边坡耐久性设计和评估分析具有重要意义。以锚喷支护边坡为例,通过几何相似比为1∶50的模型试验探讨不同弱化程度的边坡受耐久性因素影响的效果。首先基于正交设计试验确定模型边坡岩层以及喷射混凝土层相似材料配合比,进一步设计单槽尺寸0.75 m×1.5 m×1.1 m的双模型槽对比试验系统,模拟正常工况,以及降雨(7 d)+风干(7 d)、酸雨/盐雾(7 d)+风干(7 d)等边坡耐久性影响工况,基于DIC仪器测试不同工况条件下坡顶分次堆载对坡面位移变化影响。研究表明:支护结构材料耐久性能退化对边坡变形位移产生一定量影响,可为长期复杂环境影响下的边坡耐久性稳定性设计评估提供参照。

The mechanical property degradation on long-term durability of slope rock mass and the supporting structures may have influence on slope deformation and safety stability. It is of significance to carry out quantitative research to guide the durability design and evaluation analysis of rock slopes. Taking the slope supported by anchor and shotcrete as an example, the effects of durability factors on slopes with different degrees of durability degradation are investigated through physical model tests with geometric similarity ratio of 1∶50. Firstly, based on the orthogonal design test, the mixture ratios of similar materials of the model slope rock stratum and shotcrete layer are determined. Physical model comparative test system was further designed which includes double model boxes with box size 0.75 m×1.5 m× 1.1 m for each one, and do tests with the system to simulate the normal working conditions, as well as the working conditions of rainfall for 7 days plus the succeeding air drying for the same time, or acid rain/salt spray(7 d) plus air drying(7 d), etc. By using the Digital Image Correlation(DIC) instrument, slope displacement measuring is taken to investigate the impact of graded surcharge on model slopes under different working conditions. The results show the influence of material durability degradation on slope deformation and displacement, and can provide certain reference for the design and evaluation of durability degradation and stability of slopes in a long-term complex environment.