Block Stability Analysis Method Of Tunnel Surrorunding Rock Under Water Pressure And The Development Of Visual Program

With the rapid development of transportation,water conservancy,municipal engineering construction in our country,the construction of the tunnel,foundation pit,slope and underground cavern and so on has also shown a significant growth trend.Due to the lack of understanding of the engineering rock mass and the shortage of the analysis method,the rock engineering construction is also facing the engineering hazards such as landslide,tunnel collapse,large deformation of underground space and so on.Therefore,scholars at home and abroad have paid more and more attention to the study of rock engineering.The stability analysis of rock mass is one of the key problems in the research of rock engineering.By the analysis of stability,deformation and failure law of rock can be obtained,can analyze the stability of rock mass,and provide a theoretical basis for the design and construction of rock engineering.It is also the basis for reinforcement program?The engineering rock mass is cut into different blocks by joints,fissures and faults.The structural plane is the main factor that restricts the stability of rock mass.The static balance block in the state of nature is broken because of excavation disturbance,free face and applying dynamic load may cause sliding block,thereby causing instability of the surrounding rock,bring great hidden trouble of safety engineering construction and operation.Based on the block theory of Shi Genhua,the geometric parameters and mechanical properties of the structural plane are taken as the controlling factors in the stability analysis of the rock mass.The block theory has been widely used in the stability analysis of rock engineering since it was proposed.In this paper,This paper has done the following research based on block theory:(1)The basic principle of block theory is expounded The vector analysis method for the calculation of the movable block and the key block is studied,and is applied to the stability analysis of tunnel surrounding rock.The effects of the size of the block,the distribution of the structural plane and the water pressure on the stability of the block are discussed.The calculation of bolt shotcrete support based on block theory is studied.(2)An extended critical block theory--key group method is studied.The weighted average of the safety coefficients of each key block group can represent the overall stability of the rock mass system.The key group method can be applied to the stability analysis of tunnel surrounding rock mass,and the bolt support design can be optimized.(3)The influence of blasting vibration and seismic load on the stability of surrounding rock is discussed.The equivalent static method is used to convert the dynamic load into the static force.The influence of dynamic load on the action time is calculated by the block accumulation displacement method?(4)Based on the idea of structural reliability,the influence of the random distribution of structural plane parameters on the stability of rock mass is analyzed by Monte Carlo method;The failure modes and the reliability of the block are discussed when the surface of the structure is subjected to the normal distribution and the extreme value I distribution.The reliability of the block is combined with the safety factor as the two indexes to evaluate the stability of the block.(5)Based on the block theory,using Visual Basic language to develop the key block calculation program KBCALC 3.The program realizes the automatic calculation of the key block identification,the safety factor of the block and the block size.Based on the hybrid programming of Visual Basic and AutoCAD,the 3D dynamic display of block shape,block position,block failure trajectory display and block failure mode is realized.The program is used to calculate the stability of the surrounding rock of the long tunnel,and the reliability of the block and the design of bolt support are analyzed.