降雨入渗对微生物注浆加固边坡的稳定性影响研究

Stability analysis of microbial grouting slope under rainfall infiltration

利用微生物注浆加固边坡,分析降雨入渗作用下微生物注浆加固土体的非饱和土-水特征参数,并采用Van Genuchten公式进行拟合,获得微生物注浆土体渗透函数的特征参数。利用MIDAS/GTS分析降雨入渗条件下,坡面加固边坡的非饱和土体,在流固耦合作用下的暂态孔隙水压力,并用于考虑基质吸力影响的边坡稳定性计算。根据设定的降雨情况,探讨了注浆边坡在不同降雨强度、不同降雨持时的稳定性。结果表明:微生物注浆加固可以有效减小降雨入渗对边坡的影响,对提高边坡的稳定性具有明显的促进作用;相同加固方案、相同降雨持时情况下,降雨强度越大,边坡的稳定性越差,其中当降雨强度达到30mm/d时,所有加固方案的边坡处在失稳状态;降雨持时相同,随着注浆加固厚度的增加,坡体孔隙水压力负值区减少,边坡的稳定性进一步增加。

Microbial grouting is used to reinforce the slope,the unsaturated soil-water characteristic parameters of the soil reinforced by microbial grouting under the action of rainfall infiltration are analyzed,and the Van Genuchten formula is used to fit the characteristic parameters of the microbial grouting soil permeability function.Use MIDAS/GTS to analyze the transient pore water pressure under the action of fluid-solid coupling in the unsaturated soils of slopes with different slope reinforcement thicknesses under rainfall infiltration conditions,and to calculate the slope stability considering the influence of matrix suction.According to the set rainfall conditions,the stability of the grouting slope under different rainfall intensities and different rainfall durations is discussed.The results show that microbial grouting reinforcement can effectively reduce the impact of rainfall infiltration on the slope,and it has a significant promotion effect on improving the stability of the slope;Under the same reinforcement scheme and the same rainfall duration,the greater the rainfall intensity,the worse the stability of the slope.When the rainfall intensity reaches 30mm/d,the slopes of all reinforcement schemes are in an unstable state;The rainfall duration is the same.As the thickness of grouting reinforcement increases,the negative pore water pressure area of the slope decreases,and the stability of the slope further increases.