| The soil-rock dual bedding slope(hereinafter referred to as the dual bedding slope)is composed of two different strata structures,namely,the upper soil layer and the lower rock layer,and the rock layer tends to be free surface,which leads to the instability of this type of slope and the various forms of instability and failure.Based on the binary bedding high slope of ZK5+400～ZK5+840 construction project of Science and Education Avenue(Nanshan Road to Honghai Avenue)in Shenshan Special Cooperation Zone,the failure mode and stability of the binary bedding high slope are analyzed by theoretical analysis,field investigation and numerical simulation.The main results are as follows :(1)Based on the unmanned aerial vehicle(UAV)measurement technology,the field binary slope was aerially measured,and the measurement route and the setting of image control points were optimized.The slope was reconstructed by ContextCapture software.The accuracy analysis was carried out by combining the three-dimensional geometric model with the field measured inspection points and the field measured occurrence data.The elevation error,the minimum elevation error and the maximum elevation error of the inspection points were 0.0019 m,0.0008 m and 0.0032 m,respectively.The average absolute error of inclination and inclination was 2.61° and 1.89°.(2)On the basis of the three-dimensional geometric model,combined with the survey data,the elevation data and other information are extracted from the three-dimensional geometric model established by ContextCapture software through the EPS three-dimensional mapping software,and the numerical analysis model is established to simulate the slope excavation process.The failure mode of the binary bedding high slope is analyzed.It is concluded that there are five main failure modes of the slope : circular sliding along the internal soil,sliding along the soil-rock interface,sliding along the fold linear sliding inside the strongly weathered rock layer,sliding along the interface between the strongly weathered rock layer and the moderately weathered rock layer,and sliding along the internal moderately weathered rock layer.The change law of vertical displacement and horizontal displacement of slope surface : the change law of each measuring point of vertical displacement of slope shows a trend of increasing slowly at first,then mutation,and then stabilizing;on the whole,the change law of horizontal displacement of each measuring point increases slowly at first,then increases abruptly,and then tends to be stable.The slope safety factor decreases with the increase of excavation height.(3)In view of the obtained failure mode,a stability theory applicable to the two-dimensional bedding slope,namely,the oblique slice transfer coefficient method,is deduced.The engineering example is verified,and the results are compared with those obtained by numerical simulation.The verification shows that the safety factor obtained by the oblique slice transfer coefficient method is close to that obtained by numerical analysis,and the value is within a reasonable range.On this basis,the factors affecting the stability of the binary bedding high slope are analyzed,and it is concluded that the stability of the binary bedding high slope is most affected by changing the size of the structural in-plane friction angle.(4)The support design of the dual bedding high slope of Science and Education Avenue is carried out,and the support numerical analysis model is established.By simulating the slope support process,the working properties and support effect are evaluated,and it is concluded that the support method of bolt,anchor cable and lattice beam can greatly improve the stability of the slope. |
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