A layered control method for nuclear power engineering foundation blasting excavation

Abstract

The invention relates to a blasting excavation layered control method for a nuclear power engineering foundation. The blasting excavation layered control method comprises the following steps of: determining an excavation layer number and excavation depth according to foundation negative excavation depth H; determining the site attenuation rule by carrying out blasting vibration test; preliminarily determining rock mass damage depth by carrying out acoustic wave test; calculating rock mass point vibration speed and rock blasting damage depth by carrying out finite element numerical simulation; separately establishing the changing rule of mass-point peak vibration speed along with the rock blasting damage depth at positions with difference distances from a blasting source under a step blasting way and a pre-cracking blasting way; determining layered blasting excavation control standards of three distances under different blasting ways according to blasting excavation allowable damage depth of each layer; and guiding blasting design by combining the site attenuation rule to invert maximum-section dose. The blasting excavation layered control method effectively solves the problem that a three-layer excavation way of an existing method is difficult in effectively controlling damage depth and the defects that existing control standards are single, are inconvenient to use, are not suitable for the pre-cracking blasting way, and the like, so that construction progress is quickened, and relatively good economic benefits are generated.

Description

technical field [0001] The invention relates to a layered control method for nuclear power engineering foundation blasting excavation. Background technique [0002] In order to meet the deformation requirements of the main buildings of nuclear power plants (including nuclear islands, conventional islands, etc.) under the action of self-weight and seismic loads, most of my country's nuclear power plants choose relatively complete rock mass as the foundation of the main buildings such as nuclear islands, and the foundation excavation generally uses The blasting method is carried out. During the foundation blasting excavation process, along with the rock blasting and fragmentation process, the blast shock wave propagates in the rock mass medium, which inevitably causes varying degrees of damage to the underlying rock mass. Since nuclear power projects have high requirements on the integrity of the foundation surface, the blasting construction must be strictly controlled to ensu...

AI Technical Summary

Problems solved by technology

After the Fukushima nuclear leakage accident in Japan in 2011, most of the newly built nuclear power reactors in China adopt the third-generation reactor type, and the foundation excavation depth is deeper than that of the second-generation reactor type. It is difficult to effectively control the damage depth by excavating in three layers

Numerical simulation can conveniently, economically and quickly simulate the attenuation law and damage characteristics of the site under the conditions of different blasting scales, maximum charge volumes, and excavation depths, and can make up for the shortcomings of insufficient field acoustic wave test data. When determining the input load of the model explosion, the single-hole single-segment simplified treatment is performed, that is, it is assumed that all the blasting charges in the field blasting are concentrated in one blasting hole for one-time detonation, and the effect of group holes cannot be considered. The actual situation is quite different

[0004] In addition, the existing control standards are strictly defined by the peak particle vibration velocity at a distance of 30m from the explosion source. When the site geological conditions are complex, it is often difficult to deploy monitoring points and inconvenient to use. At the same time, the existing control standards and methods are all aimed at The blasting method was proposed, but on-site pre-splitting blasting required multi-hole simultaneous blasting to obtain a better pre-splitting effect, and the generated vibration was relatively large, often exceeding the control standard, but the actual damage to the underlying bedrock was not large (that is, "pseudo-exceeding the standard") ); if the pre-splitting blasting is strictly controlled by this standard, the pre-splitting effect will be unsatisfactory. Therefore, using the step blasting control standard to control the pre-splitting blasting makes it difficult to coordinate the contradiction between "pseudo-standard" and good pre-splitting effect , largely unsuitable for pre-splitting blasting

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