Study On The Disturbance Effect And Control Technology About The Small Interval Multi Cross And Pararllel Tunnel Excavation

With the development of transportation infrastructure in China, the small interval multi cross and pararllel tunnel which is not restricted by topography, track and other restrictions began to appear. In engineering practice, cross and pararllel tunnel is attracitive to domestic and foreign scholars, because its surface settlement is difficult to control and its excavation disturbance effect is obvious. Combined with the Changsha science and technology project (K0902027-1), this paper will research the surface settlement and excavation disturbance effect in the cross and pararllel section of Xiangjiang tunnel, put forward the control technology and analyze the actual effect of blasting control technology. The paper is mainly about the following aspects:(1)Expatiated on general mechanics principle of the tunnel construction and the classification, effect criterion and influence partition of the nearly meet construction in details. Then, according to the engineering practice of the cross and pararllel section of Xiangjiang tunnel, preliminarily determined the nearly degrees of this section.(2)Using numerical simulation technology, constrasted two excavation orders for the cross and pararllel section of Xiangjiang tunnel which are "take lower first" and "take upper first". The results showed that the disturbing influence of another tunnel construction is small for the "take lower first" order.(3)On the basis of the choice for excavation orders, further simulated the whole dynamic process for ramp tunnel excavation which used CRD method, and analysised dynamic disturbance effect to the lower tunnel, the adjacent ramp tunnel and ground surface with the ramp excavation process. Finally got the dynamic changes of the process of the main tunnel cross-sectional shape, cross section vault and bottom displacement, arch waist level convergence, primary support structure vault and bottom maximal principal stress, the surface subsidence and the area of the affected main tunnels with ramp excavation.(4)Combined with the engineering practice of the cross and pararllel section of Xiangjiang tunnel, this paper put forward the reinforcement effect, parameters selection and construction attention of construction technologies such as anchor, pipe roof, grouting in the tunnel project.(5)Expatiated on the blasting control evaluation criteria in details, simulated the blasting vibration of the cross and pararllel section of Xiangjiang tunnel, and combined with the measured data, evaluated the blasting control effect.