Study On The Stability Of Wharf Slope Under The Slippery Stratum

With the rapid development of inland waterway transportation, the port coastal resourcesare getting less and less and the construction of inland wharves will be faced to more complexhydrological and geological conditions. Under the action of the reservoir water level, thestability problem of wharf slope in the stratum which is easy to slide is becoming increasinglyprominent, which brings greater difficulties to wharf construction in the reservoir area.Combining with the Project of Chongqing Scientific Research "Instability mechanism anddisposal technology research of Gravity wharf in reservoir area", the method of finite limitanalysis is adopted to study the stability and its influencing factors of wharf slope in thestratum which is easy to slide in this paper and the method of displacement back analysisbased on complex variable derivation is applied to inverse the shear strength parameters ofcomplex slope soil, meanwhile, the multi-slip surfaces of less stable Wharf Slope aresearched and the reinforcement scheme is put forward. Specifically, the main research workand achievements of this paper include the following aspects:(1) On the basis of systematically analyzing the analysis methods of the existing wharfsstability, it is put forward that the strength reduction method of finite element is an effectiveway for the stability analysis of complex wharf slope and is recommended that this methodcan be applied in the analysis of wharf slope in the important slippery stratum of the inland.(2) The stability of wharf slope in the slippery stratum is related to the changing ofreservoir water level, pileup behind the wall, slope gradient, backfilling materials and shearstrength parameters of soil. Studies have shown that, the most disadvantageous water levelexisting in the wharf slope can be obtained by searching, and the faster the water leveldeclines, the lower the stability safety factor of wharf slope becomes, andthe presence of excess pore water pressure is extremely detrimental to the stability of thewharf slope, and the size and the style of the pileup in the wharf slope is also an importantfactor influencing the stability of wharf slope, and the slower the gradient of the slope is, themore stable bank slope becomes, and good backfill materials significantly improve thestability of the wharf slope significantly, and there is a positive correlation between the shearstrength parameters of slope soil and slope stability. We should pay attention to the bankslope retaining wall backfill material selection in the actual project, and should focus on thehandling of drainage in the wall, the slope ratio selection of bank slope and the control of the pileup behind the wall in operation.(3) The method of displacement back analysis based on the method of complex variablederivation is applied to inverse the shear strength parameters of complex slope soil and theresults of demonstrate that this method is of high efficiency and accuracy in inversing thegeotechnical parameters of the sliding surface for wharf slope. The generation of thesecondary sliding surface is often the reason for the incomplete treatment of under-stablewharf slope, so several potential slip surfaces of the complex wharf slope can be searched outby adopting the finite element strength reduction and constraining landslide shear crack,which provides the basis for the treatment of the under-stable wharf slope.(4) The scope of setting piles and the method of determining economic location forsetting piles suitable for wharf slope is put forward. According to searching multi-slippingsurface, we can determine the scope of setting piles suitable for the entire wharf slope and theeconomic location of setting piles can be found by comparing maximum bending moment andmaximum shear at each position.(5) The reinforcement effect and its economy of using the long piles, deeply buried pilesand the pre-stressing anchor to reinforce the under-stable wharf slope is analyzed, and theanchoring depth of pile and the selection of pile spacing is proposed, which can provide areference for the reinforcement of complex wharf slope.