| Transportation is the lifeblood of national economic development,in which road transportation plays a leading role.my country’s road infrastructure construction is now in a period of rapid development.For mountainous areas,due to the complex geological conditions such as complex terrain and special geomorphology,conventional construction plans often it cannot be carried out normally.As an important means of efficient,economical and convenient engineering construction,blasting construction has the special advantages that ordinary machinery and manpower cannot be replaced,so it is widely used in the excavation of roadbed rock high slope forming blasting engineering.However,due to the complexity of the rock blasting process and mechanism and safety accidents such as slope instability caused by blasting vibration during construction,the previous field research methods for slope blasting vibration were limited,and it was impossible to visually observe the deep inside of the slope.Therefore,the numerical analysis of the dynamic response of the slope in the excavation of subgrade slope forming has important engineering practical significance and theoretical research value.Based on the slope forming excavation project of a highway blasting construction project in Guizhou Province,this paper takes the subgrade slope forming blasting excavation section as the K86+152～K86+600 contract section to carry out the numerical simulation and theoretical analysis of the slope dynamic response.Mainly analyze from the following aspects:1.By introducing in detail the calculation basis and method of various parameters required in the dynamic analysis of the rock slope under the blasting load in the ABAQUS numerical simulation software,and by establishing the infinite element boundary and the slope finite element model for coupling analysis,it overcomes the artificial boundary has a large selection range,and the model calculation scale is huge,causing stress wave reflection and scattering effects at the boundary,affecting the calculation results and not conforming to the actual situation.2.According to the basic theory of rock blasting and the theoretical formula of equivalent calculation of blasting load,the advantages and disadvantages of the four equivalent methods are obtained through numerical calculation and analysis,and provide a basis for the source of load parameters used in the subsequent analysis of this article.3.Use ABAQUS to compare the numerical calculation results of ground stress balance and theoretical calculation results under different boundary conditions.By calculating the relative error and stress distribution of the two,the most reasonable boundary conditions in the calculation of the slope prestress field are obtained,namely Manually intercept the boundary to constrain the normal displacement.4.Determine the theoretical calculation formulas of crush zone and fracture zone in the theoretical calculation of equivalent load in the case of non-coupling based on the rock failure criterion,which provides theoretical calculations for Rc and Rf.5.Carry out 3D numerical analysis on the K86+152～K86+600 contract section of the roadbed slope forming blasting excavation section.The dynamic response results show that the blasting vibration speed is within the control standard range,and the maximum tensile stress and the first appearing area are both at the toe of the slope.Therefore,protective measures should be strengthened at the toe of the slope in the actual project.Through the comparative analysis of different initiation methods,it is found that the forward initiation vibration velocity is much lower than the reverse initiation.The forward initiation method is better than the reverse initiation when the slope vibration velocity control standard is higher and other conditions remain unchanged.The dynamic response of each measuring point of the slope under different uncoupling coefficients and the attenuation law under different variables show that the best uncoupling coefficient ranges from 1.5 to 1.6.Figure[37]table[18]reference[67]... |
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