Experiment Research On Strike Disintegration For Perilous Rock With Quasi-Masonry In Limestone Area

Rockfall is a kind of natural geological disasters all over the world,which serious threats to affect people's security of lives,property and associated infrastructure.Especially in the limestone area,because of the truth that perilous rock in this area always has typical masonry structure characteristics and there are tremendous amount of parties within a single collapse,so the caused by the consequences of the disaster is usually more serious.Based on the examples of Zhen Zi Yan Rockfall in Jinfo mountain of Chongqing Nanchuan,the article adopts the methods of theoretical analysis and indoor model test to explore the on the formation mechanism of perilous rock in limestone are,failure form and falling movement characteristics,collapse and disintegration process and excitation effect caused by disintegration.Some main research results are as follows:(1)Based on the Zhen Zi Yan perilous rock in limestone area,the article constructs the corresponding geological mechanical model and briefly analyzes the dangerous rock masonry structure formation reasons and structure near the surface weathering fragmentation region evolution.What's more,it also pointed out that the perilous rock with the appearance size of "thin-tall" always will have high bottom pressure stress,which can result to its bottom fracture and the possibility of instability damage is lager.(2)Combined with Zhen Zi Yan rockfall video data and related fracture mechanics analysis,the article roughly revealed that due to Poisson's effect,when subjected to strong impact load,the rock mass under tensile stress is the main reason for the disintegration of the bottom-up effects and bulging belly phenomenon.(3)Through the indoor model test we can see that the structure surface weathering fragmentation region is the main causing dangerous rock body vertical seat break rather than toppling failure of important factors,and it is easily to damage at the bottom of the perilous rock with "thin-tall" type appearance feature size;Fourthly,combined with the theory of science and the disintegration of the fracture mechanics theory,the perilous rock form depends on its structure and feature size.Further,whether it will produce disintegration effect and damage form and collapse motion feature is closely related to the understanding in turn.(4)In the perilous rock model test we acquired the acceleration time-histories curve using acceleration sensor of produced in the process of impact ground vibration effect and reveals the typical pulse signal characteristics with the exciting effect generated in the rock in the process of impact ground,particles on the surface of the whole process produced about 65.77ms-2 acceleration and maximum about 0.11184 mm vertical deformation.At the same time,the author confirms the dangerous rock mass in the hit the ground in the process with continuous bottom-up impact disintegration characteristics.(5)Aiming at the acceleration vibration signal obtained by indoor test model,the article has done the time-frequency analysis and acquired the result that acceleration hitting the ground excitation frequency rate is roughly about 150Hz;What's more,using db4 wavelet of the acceleration signal by wavelet transform to obtain the wavelet coefficients of different scales and displacement factor,and the decomposed wavelet coefficients based on the signal elimination noise and multi-resolution signal analysis.general detail coefficients shows that vibration signal contains strong pulse signal characteristics.