Seepage Failure And Spontaneous Potential Response Of Filling Fractures Experimental Research

Seepage failure of filling fractures is an important research content in the field of environmental geological engineering,which may lead to serious environmental geological problems such as ground collapse,dam foundation instability,slope damage,and engineering water damage.In this paper,taking advantage of the Self-potential(SP)technology in monitoring groundwater flow migration,in order to design and process the seepage model of the filling fractures and information identification problems,the filling fractures seepage model is designed and processed,the filling fractures seepage damage test is carried out,and the particle composition and flow direction of different filling media are studied.Seepage failure characteristics of filling fractures under the conditions of fracture width and fracture width.Real-time monitoring of SP change data during the seepage failure test,clarifying the SP response characteristics,and discussing the relationship between the critical hydraulic gradient,the uneven coefficient of filling and SP during the seepage failure of the filling fracture relationship.The main research contents and results are as follows:(1)Macroscopic seepage failure characteristics of filling fractures:(1)The development process of seepage failure is divided into four stages: no significant seepage failure phenomenon,significant seepage failure phenomenon,seepage channel generation and development upstream,and complete destruction of the filler.(2)The critical hydraulic gradient J,the total amount of particle loss,the critical seepage flow q and the uneven coefficient Cu of the filling medium are negatively linearly correlated.The seepage angle ? changes from 0°(horizontal)to 90°(vertical).The total particle loss,the critical seepage flow q and the seepage angle ? are negatively correlated,and the critical hydraulic gradient J has a positive correlation with the seepage angle ?;filling the fissures The larger the width,the smaller the critical hydraulic gradient J,the total particle loss,and the critical seepage flow q.(2)Self-potential response characteristics of filling fracture penetration failure:(1)When approaching critical penetration failure,the closer to the water inlet,the greater the SP fluctuation range;near the water inlet 1# electrode SP responds first,and 2#?4# electrode subsequently responds in turn,Each monitoring electrode has a corresponding maximum amplitude fluctuation,and the natural potential difference(?SP)along the seepage direction decreases sequentially.The larger the gap width of the filling fracture,the smaller the critical ?SP;the seepage angle ? changes from 0°(horizontal)to 90°(vertical),and the critical ?SP decreases.(2)When critical seepage failure occurs,the maximum ?SP of the monitoring electrode decreases exponentially with the uneven coefficient of filling Cu;the average hydraulic gradient J at each monitoring point and the critical ?SP are in a positive linear function;the critical ?SP at each monitoring point is related to the flow seepage The straight-line distance L in the direction has an exponential function relationship.(3)Using the function relationship between the critical ?SP of each monitoring point and the straight-line distance L of seepage flow to calculate the ?SP at other points inside the fracture,and then calculate the critical average hydraulic gradient at the required point inside the filled fracture through the critical ?SP of this point.Comparing the actual observation value with the calculated value,it can be seen that the relative error of the average hydraulic gradient at each point in the fracture calculated according to ?SP is relatively small.