Pre-splitting blasting construction method for shield tunneling in upper soft and lower hard strata

Abstract

The invention discloses a pre-splitting blasting construction method for shield tunneling in upper soft and lower hard strata. The pre-splitting blasting construction method for shield tunneling in the upper soft and lower hard strata comprises the following steps that according to a determined blasting area, pre-splitting blasting hole arrangement is carried out, specifically, hole arrangement forms of blasting holes, auxiliary holes and shock absorption holes are included, and drilling construction is carried out after the hole arrangement is qualified through acceptance; after the drillingis completed, the explosive quantity calculation and charge processing are carried out, then a charge structure is determined and the initiation network is designed; anti-floating counterweight of explosive, charge emplacement and protection are carried out, then initiation is carried out, and the blasting effect is tested after completion of blasting; after the blasting construction is completed,the remaining holes are sealed and blocked to avoid slurry leakage when a shield passes through the blasting area, and after the hole sealing is completed, shield tunneling is carried out. The pre-splitting blasting construction method greatly saves the construction cost of the shield and can effectively solve the technical problem of processing boulders and hard rock sections encountered in shield tunneling by adopting the pre-splitting blasting technology for the sections.

Description

technical field [0001] The invention relates to the technical field of tunnel engineering blasting by shield tunneling method, in particular to a construction method for pre-splitting blasting in upper soft and lower hard strata for shield excavation. Background technique [0002] In recent years, with the rapid development of urban rail transit construction, more and more cities have begun to build large-scale urban rail transit such as intercity railways. The construction of track sections in most cities adopts shield tunneling method. During the construction process, randomly distributed boulders and bedrock protruding upper soft and lower hard strata are often encountered, and the boulders have different shapes and sizes and different strengths, and the hard rock has extremely high strength. [0003] The construction of the shield method in the upper soft and lower hard geological layers is likely to cause some problems: for example: 1. In this type of stratum, the excav...

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Problems solved by technology

[0003] The construction of the shield method in the upper soft and lower hard geological layers is likely to cause some problems: for example: 1. In this type of stratum, the excavation efficiency is low, the cutterhead and cutter wear are serious, and it is easy to cause cutter jamming, inclined cutter, cutter drop, and partial wear of the cutter, etc. , the processing speed is relatively slow, seriously affecting the construction progress, and some even have to change the design because the construction cannot progress, the cost is high, and the economic benefit is poor; The problem of ground subsidence has a huge impact on the surrounding environment, and it will also cause serious wear and tear on the excavation tools

3. In the hard rock section, not only the excavation side hob wears quickly, but also the shield machine is prone to jamming. Therefore, frequent tool opening inspections are required, which increases the construction risk; 4. The soft and hard geological strata are in the lower The slope section has a certain negative impact on the excavation construction

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