Stability Analysis Of Filling Slope Of Centianhe Main Canal

Cen Tianhe Main Canal Project is the no.1 water conservancy construction project in Hunan Province,with a length of 240 km.When the slope is filled,there is no step excavation and no retaining is set at the slope foot,so there is a risk of insufficient stability in the construction and operation period of the channel.Hydrogeological conditions were investigated on site,physical and mechanical parameters of rock and soil were determined,and numerical model of channel slope was established.Based on FLAC3D reduction construction process,the design scheme was reviewed to evaluate the stability of slope during construction period.Based on the self-programmed unsaturated rainfall seepage program,rainfall seepage is calculated during the channel operation period to evaluate the stability of slope during operation periodThe main contents and conclusions are as follows:(1)Potential risks during construction and operation of the channel.Through the field investigation of the filling slope,the analysis of hydrogeological conditions,and the identification of potential risks during construction and operation of the channel,the slope filling,there are poor mechanical properties of the filler,no excavation leveling,slope foot without retaining and other risks;During the operation of the channel,influenced by rainfall,the channel and underground water level rise,which reduces the friction Angle and cohesion of surrounding rock and soil,increases the weight degree of rock and soil,and reduces the shear strength,thus increasing the probability of instability.(2)Design review and parameter sensitivity analysis of excavation and filling during construction.The excavation and filling conditions are simulated under natural conditions,and the excavation disturbance deformation,stress and slope safety factor are calculated.The calculation results show that:under natural conditions,the excavation and filling are in a stable state and meet the requirements of the code.In filling condition,the sensitivity of each factor to displacement is in the order of cohesion>internal friction Angle>elastic modulus>density>Poisson’s ratio.(3)Analysis of rainfall seepage law and stability during channel operation.During the rainfall period,the vertical face pressure of slope increases with the rainfall intensity and duration,and the growth rate of pore pressure decreases from top to bottom in the range of rainfall infiltration depth.At the beginning,rainwater flows downward through rock mass gap medium as seepage channel.With the increase of rainfall duration,it changes to flow along the quaternary overburden to the foot of slope when it infiltrates to the contact surface between earth-rock filling body and quaternary overburden layer,and the displacement of the contact surface is the largest,and the filling slope is prone to sliding failure along this contact surface.(4)Common problems and countermeasures of channel slope during operation.According to the characteristics of the channel filling slope and the common problems of infiltration,damage and crack in the operation period,countermeasures are proposed.According to the numerical simulation results,key monitoring positions are determined,a low-power remote monitoring system based on the Internet of Things is constructed,and monitoring schemes and monitoring analysis are proposed.