Construction method for ultra-short-distance overlapped line tunnel long-distance guide pit advance control bursting

Abstract

The invention discloses a construction method for ultra-short-distance overlapped line tunnel long-distance guide pit advance control bursting. The construction method includes following steps: excavating an advance hole of an overlapped lien section; determining basic data of bursting network designing; determining bursting key parameters; determining bursting mode; constructing a bursting cloth hole of a long-distance guide pit; constructing a bursting cloth hole of a short-distance arch pit; setting bursting parameters; arranging explosive; detonating the long-distance guide pit; detonating the short-distance arch pit; reinforcing preliminary support. Aiming at the characteristic of minimum net-distance section construction, designing optimizing is majorly performed on bursting scheme, so that bursting disturbance degree is reduced. Maximum section explosive loading capacity is adjusted by selecting half-section bursting network design for sectional bursting and combining a distance between two lines of the advance hole and a following hole with requirements on bursting vibration speed, so that good construction effect is acquired.

Description

technical field [0001] The invention relates to a construction method for underground excavation of a superimposed line tunnel, in particular to an underground excavation method for an ultra-short distance superimposed line tunnel with long-distance pilot pit controlled blasting in advance. Background technique [0002] With the vigorous development of urban subway construction, the urban underground space has been continuously developed and utilized, and there are more and more small distance tunnels. For the tunnel with small clear distance, the thickness of interlayer rock mass is relatively thin, which becomes the weak link under force due to the multiple disturbances of blasting excavation, and the stability of surrounding rock is poor. Therefore, the protection of interlayer rock mass during construction will be Very important. The most important and difficult points in the construction of small-space tunnels are how to reasonably select the excavation sequence, contr...

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Problems solved by technology

[0004] The purpose of the present invention is to provide a construction method for super-short-distance stacked-line tunnel long-distance pilot-pit pre-controlled blasting, to solve the problem existing in the excavation process of the stacked-line tunnel in the prior art. The rock mass is unstable and damaged, the upper hole will produce uneven settlement when the lower hole is excavated, and the technical problem that the structure may crack

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