Study On Variation Of Earth Pressure Of Double-river Culvert And Influencing Factors

In mountainous cities,the double-layer river channel is a new type of river channel that is superior to other river channels.The upper open channel has the functions of safety,leisure,and hydrophilicity.The lower layer culvert is mainly used for flood discharge and drainage.Stand out from the crowd.At present,the current theories and codes have no relevant research and regulations on the calculation of the earth pressure of double-layer river culverts.Therefore,studying the change law of earth pressure under the action of the fluid-solid coupling effect of the change of the groundwater level of the double-layer river channel structure has important engineering applications value.This paper analyzes the characteristics of culvert earth pressure for static water level conditions,water level drop conditions,variable cross-section conditions,and variable permeability coefficient conditions,and compares the numerical simulation results with the results of the normative empirical formula.Based on actual engineering,this paper established a two-dimensional finite element model of two-layer river channel for numerical simulation.The main research contents and conclusions are as follows:(1)By reviewing the literature and referring to actual projects,the structural characteristics and applicable conditions of the double-layer river channel were elaborated in detail,relying on the geological survey report and corresponding geotechnical experimental results of the weir river diversion project in Longzhou Bay B,Banan District,Chongqing City,and the use of SPAW The software analyzes the soil and water characteristic curve of the model,and gives the basic parameters of the model in the process of Abaqus modeling.(2)The vertical earth pressure on the culvert does not change linearly with the height h of the cladding,but changes non-linearly.When the height of the cladding increases to a certain height,the vertical earth pressure of the culvert cannot be directly solved by the soil column method,which will The designed culvert structure is too large,uneconomical,and even wasteful;There is a large difference in the vertical displacement of the culvert and the soil outside the culvert,which leads to the so-called stress concentration at both ends of the culvert.(3)In the case of unsaturated seepage,the stress concentration at the two ends of the culvert roof is more obvious than that in the anhydrous condition,the vertical displacement of the soil is large,and it is easy to cause damage to the upper building due to uneven settlement.Therefore,anti-seepage measures should be taken in the upper open channel.Downward penetration of water.(4)When the overburden height is low(0-15m),the earth pressure value can be directly calculated using the Marston bulk limit equilibrium method.When the overburden height is large(15-30m),the earth pressure value is the Marston bulk limit1.1 times the calculated value of the balance method.(5)Under the condition of variable permeability coefficient,as the permeability coefficient increases,the smaller the average value of vertical earth pressure above the culvert,the smaller the pore water pressure;According to the comparative analysis of the size of different structural models,in the practical application of the project,the form of wide and shallow sections should be adopted.