A Study On Slope Drainage Mechanism And Clogging Effect Under The Function Of Soft Permeable Pipe

Engineering construction usually needs to excavate and support the mountains due to space utilization and urban planning.As permanent facilities,the long-term stability problems of slope engineering have become increasingly prominent.Underground drainage system which is an important part of the slope engineering plays a crucial role to maintain slope stability.In view of the typical residual soil slope in Fujian Province,we carry out the indoor model test of slope to fully expand the research on drainage mechanism and clogging effect of deep soft permeable pipe under abundant supply at the rear edge of the slope.Combined with the Plaxis finite element software to analysis slope drainage effect under the function of soft permeable pipe,which obtained the variation law of slope seepage field under the condition of different kinds of soft permeable pipe laying.Based on the indoor model test of slope and finite element numerical,measuring the volumetric flow rate exiting the drain,clogging increase in drain mass and clogged surface area of filter with the help of advanced digital microscope equipment and measurement methods to study the degree of clog's occurrence,development and evolution law.The main results obtained are as follows:(1)On both sides of the slope model,the penetration rate of water is faster,followed by the middle.On the bottom and trailing edge part of soil model,the penetration rate is faster,the middle part of the soil is more slowly,the main reason which causes this phenomenon is that the penetration rate of water is decided by the boundary of the constraint effect and percolation path.(2)The soft permeable pipe with different dip of angle has a significant influence on seepage field.The inclined angle of the permeable pipe is slow,the seepage in soil is first gather together,and with the loss of fine particles,the size of seepage channel is increasing,and the density of soil is decreasing.The low dip angle of drainage area is several times larger than that of the high dip angle at the later stage of drainage.(3)The lower end of the soft permeable pipe which is plugged has a significant influence on the increase of drainage effect.When the trailing edge of slope is given a certain amount of water,the groundwater flow is priority to the channel with better permeability,the strength of seepage of the other parts is smaller than before,and the damage of favorable drainage channel is more serious.(4)The result of numerical analysis shows that the increase of groundwater level,the increase of pore length of permeable pipe,and the lower end of the permeable pipe which is plugged can effectively improve the water conductivity of the permeable pipe.The effect of pore enlargement of permeable pipe on the discharge capacity is small.The elevation and the angle of elevation are needed to consider the influence of the arrangement of these which is on the relative position between the water pipe and the groundwater level line.The deeper of the permeable pipe is,the larger of the range can be control,and could have a better conductivity of water.(5)The use time of soft permeable pipe,the discharge speed and the variation of the water head on the degree of clogging of the permeable pipe basically showed that the clogging increased rapidly in the early stage of drainage,and the fine particles in the soil were carried by the water flow and fine particles became less and less,so the degree of clogging had a regression trend of gradual decline trend;(6)The essence of clogging of soft permeable pipe is the result of the migration of fine particles in the soil.In a certain degree of credibility of the degree of clogging,the soft permeable pipe is still able to play an effective drainage function.