| Wenchuan County-Li County of dry and warm valley in Mingjiang, moraineaccumulation body widely distributed, with unique engineering geologicalcharacteristics. Due to its special characteristics and formation process provenance,and other sediments is different, moraine widely distributed in the grain sizecharacteristics, mechanical characteristics of different particle size and distribution ofcontent affected.2008Wenchuan earthquake, magnitude reached8.0, induced a lot ofslope instability. So to carry out the seismic response of the slope, the slope ofimproving governance earthquake zone has important theoretical significance andvalue of work. This article from the moraine slope deformation and failurecharacteristics of departure, where the region based on the analysis of engineeringgeological conditions of the pile, through a large number of laboratory tests, FLAC3Dlimit equilibrium analysis and numerical simulation work on the pile to start asystematic study and moraine matter accumulation body characteristics, calculated onthe seismic stability of the slope parameter selection to obtain understanding of thefollowing aspects:(1) Accumulation Area Jiangjunbei slope is Zagunao Valley landscape. Therescarp slope development,was chair-shaped trailing edge. Plane approximatelytrapezoidal shape, slope ramp about589m, a width of659m, the average thickness of45m, area of38.84×104m2, a volume of about1742×104m3, slow down the steep slope,slope20°~55°.After the earthquake did not occur significantly undermine the overallinstability.(2) By conventional triaxial test,dynamic triaxial test of physical and mechanicalproperties of the pile tills were compared to test. Under natural conditions, theconventional triaxial test results moraine strength c=35.45kPa, Φ=29.75°, dynamictriaxial test results moraine strength c=9.00kPa, Φ=12.78°. It was indicated that thesame kind of test conditions, the resulting conventional triaxial strength greater thanmoraine dynamic triaxial test strength. Moraine cohesion with increasing moisturecontent tends to increase, and internal friction angle with increasing moisture contentdecreased. (3) Proceeds using conventional triaxial test of strength parameters, calculate theslope stability factor in the natural conditions of the storm, in line with localconditions. Earthquake intensity parameter condition is one factor to be earthquakeseismic acceleration0.20g, the software calculates the slope by GEOSLOPEconditions in the earthquake stability coefficient is less than1, inconsistent with theprevailing circumstances, the value of high seismic acceleration.(4) By using of dynamic triaxial tests resulting dynamic strength parametersGEOSLOPE software to calculate the slope stability factor is greater than1, in linewith the circumstances..(5) Orthogonal method combines strength parameters and geoslope software,relationship between seismic acceleration and stability coefficients proposed seismicacceleration recommended value0.17g.(6) By Numerical Simulation (FLAC3D) for two different body parametersanalyzed the accumulation of stress and deformation characteristics when appliedusing different seismic peak acceleration. The results show that: the use ofconventional mechanical parameters applied when0.20g peak acceleration of theprocess after the earthquake acceleration curve slope along the shear strain incrementChivu interface through; mechanical parameters applied using conventional seismicpeak acceleration0.17g, the local concentration of the plastic zone slope in thevicinity of the trailing edge of the scarp, through the phenomenon does not appeare.the former is more in line with local conditions.(7) Jiangjunbei slope to local landslide slip deformation mainly under theinfluence of external triggering earthquakes and other factors, there is a possibilitythat local buckling decline. In particular, strongly influenced by the landslide area,have emerged as some of the lot free face, already in the stage of creep deformation,human living water, water infiltration and engineering activities under torrential rainand earthquakes are likely to lead to instability. For already sliding off the slope,although its potential to greatly released, but did not rule out the occurrence of speciallocal conditions may even undermine the overall slide... |
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