Research On The Influence Control Of Tunnel Construction On The Adjacent Sensitive Laboratory And Its Surrounding Buildings

The thesis is based on the tunnel engineering construction of the national precision gravity measurement project of a key university.It is aimed at the construction technology problems of the new cave laboratory tunnel on the university campus under the geological conditions of broken surrounding rocks and the surrounding complex building structure.It controls the adjacent tunnels.A series of researches were carried out on key technologies affecting the surrounding environment during mechanical construction and drilling and blasting construction respectively to guide the safe and rapid completion of the tunnel construction,and to control the impact on the precision laboratory within the required range.Mainly include the following research content:(1)Conducted investigation,research and analysis on the current status of research on the impact of tunnel drilling and blasting construction in neighboring precision laboratory tunnels at home and abroad,and in-depth demonstration of the feasibility of blasting construction when the tunnel entrance section and underground connecting section tunnel are adjacent to ground buildings and precision laboratory tunnels respectively,and The safety and stability control standards,vibration control standards and noise control standards of adjacent existing laboratory tunnels have been formulated.(2)Through the three-dimensional finite element software FLAC 3D numerical simulation and comparative analysis of on-site monitoring data,the tunnel construction method and support parameters of the tunnel entrance section are optimized.The construction method for the shallow buried section of grade V surrounding rock is optimized from the three-step and seven-step method to the step method;the construction method and support parameters of the general section of the grade IV surrounding rock are optimized to 2m footage without core soil bench method excavation and inverted arches are eliminated as sprayed concrete.The support type of the initial support.(3)Using three-dimensional finite element software calculation,the vertical propagation law of vibration velocity of the upper step blasting excavation at the entrance of the tunnel is obtained,that is,the greater the distance from the excavated area,the more obvious the amplification effect;and then the K+070 is used as the entrance of the tunnel.The feasibility of the starting point of segmental blasting was studied,and the results showed that the vibration speed of each building monitoring point on the ground surface was within the range of safety standards when the blasting and excavation started at K+070.(4)The blasting end position and blasting interval position of the connecting section of the new and old tunnels are studied.When the original plan 1.2m blasting footage is adopted,the blasting excavation must be stopped before K+493 and switched to mechanical excavation;after optimizing the blasting cycle footage to 0.6m,the blasting end point is extended to K+516,which increases the length of 23 m.The interval of blasting excavation.