Study On The Creep Failure Rule Of Non-penetrating Fractures In Antidumping Slope After Earthquake

Strong earthquakes tend to cause some damage to the mountain in the earthquake zone,resulting in a large number of seismic cracks in the slope which are not easy to be found.The rock mass at the damaged site will produce rheological phenomena with time,which will lead to the expansion and connection of seismic fractures.As the seismic cracks in different parts of the slope merge and merge,the failure boundary will be formed in the slope,which will affect the stability of the slope,lead to the instability of the slope and cause geological disasters.Therefore,it is of great practical significance to study the creep characteristics of the internal cracks in the slope and reveal their fracture and connection rules in different time periods for disaster prevention and reduction and geological disaster management in the mountainous areas with strong earthquakes.In this paper,the tensile crack strain law of the fractures developed in different parts of the antisloping slope under low,medium,three or three different centrifugal accelerations is discussed.Similar in three theorem is deduced using parameters,reference and than choose the research achievements of predecessors to determine the proportion of bedded rock plate of similar material,established the pour layer seismic damage of rock mass slope centrifuge model,and carried out the centrifuge model test,obtained under the condition of different acceleration,the crack at different monitoring points of the cracking strain curve;The fracture strain characteristics and creep characteristics of non-fracture fracture under different centrifugal acceleration are studied.Finally,the indoor centrifuge test was simulated by PFC2D,and the creep failure rules of non-penetrating cracks in different parts of the slope and the meso-evolution mechanism of cracks in the slope were mainly studied.The following results were obtained:(1)By selecting similar materials,the proportion of similar materials in the slope was determined,and the preset cracks in different parts of the slope were placed to replace the cracks with seismic damage.Based on the three laws of similarity,a centrifuge model was established and the centrifuge model test was carried out.When the test is completed,the fracture connection modes at different locations of the slope are analyzed,and two major fracture assemblages and seven fracture modes are obtained(2)According to the strain curves monitored in the seismic damage crack tests at different parts of the slope,it can be seen that the stress mode of the seismic damage crack is related to the magnitude of the centrifugal acceleration.Under the condition of low centrifugal acceleration,the cracks are mainly subjected to compression and compression rebound.Under the condition of centrifugal acceleration,the stress state is more complex,which is dominated by tension and compression rebound.Under the condition of high centrifugal acceleration,the fracture state is mainly under tensile rebound and compression.(3)Based on the analysis of the strain curve when the fracture occurs,the strain change of the fracture is time-dependent.In addition,the fitting curve of tensile strain and time of most unfractured fractures under different stable acceleration conditions satisfies the quadratic function equation:()=(6(6~2+(7(7+(8(8.(4)Through the simulation of the centrifuge model test,it is found that the fracture connection development of non-penetrating fractures in the slope is not only related to the slope structure,but also related to the position and Angle of seismic damage cracks in the slope.At the early stage of the evolution of the seismic damage slope,the seismic damage fracture occurs in the middle of the slope about 1/3 of the slope.In the middle period of evolution,the fracture connection of seismic fracture is the most active,developing towards the lower and upper part of the slope,and the fracture surface near the slope surface is formed initially.At the later stage of slope body evolution,the cracks in different parts of the slope merged and formed multiple fracture surfaces in the slope body,which affected the stability of the slope body.(5)Through the analysis of the meso-mechanical characteristics of the seismic fracture at the same position as the physical test,it is found that the fracture mechanics evolution results at the monitoring points of the physical test and the numerical test are consistent.The micromechanical characteristics of seismic fracture are affected by the size of centrifugal acceleration and the position of the fracture.