Research On Dynamic Stability Of Cracked Structure Rock Mass And Seismic Reinforcement In Strong Earthquake Zone

When building project in earthquake zones,The stability of the slope has importantsignificance for disaster prevention and mitigation in earthquake.Special attention should bepaid to the highway slope seismic stability. Cracked structure slope dynamic instability hasits own features in earthquake.Rock mass fracture and the structure plane development willmake cracked structure slope failure and instability is different from homogeneous rockslope in the earthquake.Research in the regularity of failure of cracked structure slope underearthquake and engineering reinforcement effect has important significance for stability ofcracked structure slope.Based on the Guanggan highway cracked structure slope as theresearch object, use the experimental and numerical simulation method, the strongearthquake zone in cracked structure slope dynamic stability and seismic reinforcement asthe research topic. The main research results are as follows:1Through the rock dynamic experiments indicate that cracked rock structure dynamicmainly failure is tension failure along structure plane. Rock schistosity surface control rockfailure model.2In cyclic loading test indicate that while cyclic loading number increase, thedynamic strain hysteresis loop gradually to increase with dynamic strain in thedirection.While Cycle loading stress level is low, a comparatively large irreversibledeformation arose from loading and unloading cycle; Along with the dynamic stressamplitude increase, the area of the hysteresis loop increased gradually; Along with increaseof the dynamic stress amplitude and number of cyclic loading, the plastic deformation ofChlorite schist increase, The greater the stress amplitude by the cyclic loading, the bigger thedamage of the irreversible deformation.Under the same confining pressure,Dynamic elastic modulus of Chlorite schistdecreases with the increase of cycle times.Under the same number of circulation Dynamicelastic modulus of Chlorite schist increases with increasing confining pressure.Under thesame confining pressure,Dynamic poisson ’s ratio fluctuate with the increase of cycle timesin a small range,The results show the dynamic accumulated damage effect of cyclic loadingon the rock.3According to the numerical simulation for the failure process of the cracked structureslope.Used the UDEC under the earthquake shows that, the earthquake can cause thestructure of the cumulative damage,there by accelerate the structural expansion, penetration,result in the slope rock mass occurred tension failure along the structural plane, broken rock fall, even being thrown form deposits body at the foot of the slope;When slope startsliding,the dynamic effect of the earthquake accelerate the sliding; The failure process showsthat the failure is mainly controlled by the structure plane and accelerated by the earthquake,which is in good agreement with the rock dynamics experimental results.4According to the seismic dynamic response of the slope before and after thesupporting used Flac3d, the description frame anchor structure support can significantlyimprove the mechanical properties of slope rock mass, especially the preloading andretaining function provided by the pre-stress of the frame anchor structure for surface of thecracked structure slope,which can significantly improve the plastic zone distribution of thecracked structure slope.Under seismic action of the earthquake. The existence of thepre-stress also can reduce or alleviate the development and breakthrough. After thegrouting and pre-stressed tension of the anchor cable, the mechanical properties and thestability of the control planes surface can be improved. After supporting, the dynamicresponse, like the displacement, velocity, acceleration, was significantly reduced.5Under the earthquake, the internal force of the frame structure increases significantly,the higher of the frame location, the greater of the force value. the internal force of the framewhich at the top of the hill is obviously higher than that at the bottom. Under the seismicaction, the axial force of the pre-stressed anchor cable increases significantly, the increasingcoefficient associate with the anchor position.The maximum of the increasing coefficient isat the slope toe mid, which is significantly more than that at two sides, and the higher of theframe location, the smaller of the axial force increasing coefficient. Anchor shaft forceincreasing coefficient substantially equal at the same height, except at the toe of the slope.6According to the comparison of the calculated results with different anchor spacing,different anchor length and different pre-stressed.Anchor supporting parameters shows that,Under the earthquake,the impact of the cable spacing to the horizontal displacement is thebiggest, the second is the pre-stress of the cable and the minimum is the length of thepre-stressed cable.7The numerical simulation of the conditions of the original support of the Guangganhighway cracked structure slope analysis, The original design of the support is morereasonable for ensuring the dynamic stability of the slope in the strong earthquake. Throughanchor structure damage analysis, the original support can take details of seismic design.