| With the sustained,high-speed,stable and healthy development of Chinese economy,the number of engineering construction projects in mountainous areas increases continuously.However,the instability of slopes still occurs from time to time,which brings great challenges to infrastructure construction and maintenance safety in China."Ninety percent slopes have its underground water",and the main factor inducing slope instability is commonly the rainfall.Therefore,it is necessary to carry out the design and research of comprehensive drainage system in combination with the actual water disaster of slope engineering,to quickly deal with the potential hazards of slopes.At present,empirical formulas are mainly used to calculate the slope drainage in the relevant specifications,and the three-dimensional slope seepage and stability analysis considering the real undulating slope surface need to be further studied.In this study,based on the actual slope engineering,a three-dimensional slope analysis model with real undulating slope surface is built based on Rhino and COMSOL software.The transient slope stability analysis is carried out with the coupling of seepage and stress.The calculated critical infiltration amount is taken as the starting point,and the three-dimensional slope waterproof and drainage design and application research are carried out under rainfall conditions.The main researches are as follows:(1)According to the classification of rainfall grade by the meteorological department and the regional rainfall meteorological data,the most unfavorable design rainfall scheme for the actual slope is proposed using the hydrological and hydraulic method;the Rhino software was used to build a three-dimensional model of natural slope before excavation,which then was imported into COMSOL software to develop the coupling calculation of unsaturated soil seepage-stressdeformation under rainfall.The initial conditions before rainfall and the distributions of slope pore pressure,effective saturation,plastic strain and displacement field during rainfall were obtained;(2)Combined with the strength reduction method,based on the safety factors of the three-dimensional slope at the critical instability state before and after the rainfall and analyses the variation of the slope seepage field under the rainfall condition,the design extreme rainfall duration value of the slope at the critical stability state is calculated,and the method of calculating the slope drainage design critical drainage amount is proposed.Based on an actual engineering example,the drainage design is carried out according to the critical drainage volume of the slope,and the relationship between the size of the drainage measures in a cross section and the slope angle is obtained,which can provide a useful reference for the drainage design of the slope engineering;(3)The comprehensive drainage design application and treatment design effect analysis of a slope with excavation and a landslide treatment project were carried out.Based on the analysis of irregular threedimensional slope runoff characteristics,the slope confluence routing model and slope runoff,the comprehensive waterproof and drainage scheme design is proposed.The comprehensive drainage system is composed of slope surface drainage,shallow surface pipe drainage and deep internal drainage,which fully removes surface runoff and groundwater,and the saturation of the whole slope,displacement and plastic strain effectively reduced,which increases the treatment effect of sliding slope a lot.This work can provide a useful reference for the design and treatment of waterproof and drainage of similar projects. |
