CN110940242B

CN110940242B - Blasting excavation method for deep crack containing slope rock mass

Info

Publication number: CN110940242B
Application number: CN201911317006.0A
Authority: CN
Inventors: 唐杰伟; 卢文波; 刘昕鑫; 陈明; 郑祥; 王德明
Original assignee: Wuhan University WHU; Sinohydro Bureau 7 Co Ltd
Current assignee: Wuhan University WHU; Sinohydro Bureau 7 Co Ltd
Priority date: 2019-12-19
Filing date: 2019-12-19
Publication date: 2022-06-21
Anticipated expiration: 2039-12-19
Also published as: CN110940242A

Abstract

The invention discloses a blasting excavation method for deep crack containing slope rock mass. The method comprises the following steps: drilling holes and obtaining the distribution of joint fractures, dividing the blast holes passing through the fracture area into a lower coupling explosive loading section, a fracture area weakening explosive loading section and an upper conventional explosive loading section according to the distribution of the fracture area in the blast holes, carrying out blast hole explosive loading in sections, blocking the blast holes, carrying out networking initiation on the blast holes in sections with the joint fractures mutually communicated, carrying out networking initiation on the rest blast holes in sections, and carrying out hole bottom initiation on each hole. The explosive cartridge adopts segmented charging, the charging is weakened in a fracture area, and rock debris is used for filling the interval between the explosive cartridge and the blast hole wall, so that the explosive gas can be prevented from leaking too early through a joint fracture, the pressure peak value and the duration time of the explosive gas can be improved, and the 'gas wedge' effect of the explosive gas can be fully exerted; the blast holes with the joint fractures communicated with each other are subjected to grouping networking initiation, so that the condition that the blast holes are initiated firstly and then are initiated secondly through the joint fractures can be avoided, and the occurrence of misfiring accidents is avoided.

Description

Blasting excavation method for deep crack containing slope rock mass

Technical Field

The invention belongs to the technical field of engineering blasting, can be applied to blasting excavation operation of a slope rock mass with joint crack development, and relates to a blasting excavation method of the slope rock mass with a deep crack.

Background

The mountains of China are numerous, the mountains are particularly widely distributed in western regions, and with the continuous development of national economy, various engineering constructions extend to the western regions. When various engineering constructions are carried out in the high mountain canyons, blasting excavation of side slope rock masses is indispensable. A large number of fractures are often present in rock masses under the influence of various geological formations and long-term physical, chemical and biological weathering attacks. Generally, it is believed that rock fracture under the action of blasting is the result of the combined action of explosive stress wave and explosive gas, after the explosive is exploded, firstly, a large number of new cracks are generated on the wall of the blasting hole under the action of the explosive stress wave, and simultaneously, the original cracks are expanded, then, the quasi-static pressure of the explosive gas enables the radial cracks to be developed into main cracks along one or more directions, and the expansion of the main cracks is just the expression of macroscopic fracture. If the rock mass has a large number of joint cracks before blasting, the integrity of the charge segment can be damaged, so that the blasting gas can be leaked out prematurely, and the blasting effect is reduced. On the other hand, when the blast holes with joint fractures communicated with each other are encountered, the blast hole detonated first can have adverse effects on the blast hole detonated later, and in severe cases, the detonation network is damaged, even a misfire accident occurs, and great potential safety hazards exist. In order to eliminate potential safety hazards, a high-precision detonator hole-by-hole detonating network can be adopted, but the method is difficult to improve the rock blasting effect and cannot fundamentally solve the problem of the fracture leakage of the explosive gas management. In order to improve the blasting effect, a common idea is to treat cracks in a rock mass, for example, in the treatment method disclosed in CN 102979103A, CN 104005417 a, the rock mass is grouted through a special grouting hole, and after a consolidation composite layer with a certain thickness is formed, a blast hole is drilled for blasting excavation; another idea is to fill a specific substance between the explosive and the rock mass, such as the method disclosed in CN 105737697 a, directly pour cement slurry into the blast hole, use cement slurry as coupling medium to improve the strength and integrity of the rock mass, and detonate the explosive before the cement slurry is initially set. In practical engineering application, a high-strength PE flexible water pipe is used for containing the emulsion explosive and then is placed into the blast hole, so that the explosive is in a relatively closed state, and premature leakage of explosive gas is avoided.

When the rock mass is grouted, additional grouting holes need to be drilled, so that the working time of a drilling machine is prolonged, and when the blasting area is large, the number of the grouting holes to be drilled and the using amount of grout are large, so that the cost is increased for the project, and the economical efficiency is poor; grouting cement slurry into the blast hole, so that the space is narrow, the construction operation is inconvenient, and the filling effect on tiny cracks around the blast hole is difficult to ensure; the method for loading the explosive into the PE soft water pipe needs to cut the water pipe according to the depth of the blast hole and tie the lower end of the water pipe, which brings great inconvenience to the explosive loading process. Aiming at blasting excavation work of a slope rock body with a deep crack, a blasting excavation method which can give consideration to both blasting and rock breaking effects and blasting safety is found, and the blasting excavation method is necessary to overcome the defects in the prior art.

Disclosure of Invention

The invention aims to provide a blasting excavation method for a slope rock mass with a deep crack, which avoids premature leakage of blasting gas through a joint crack, improves the blasting and rock breaking effects, and eliminates the potential safety hazard of blasting holes with mutually communicated joint cracks during blasting.

In order to achieve the purpose, the invention is realized by the following technical scheme:

a blasting excavation method for deep crack containing slope rock mass comprises the following steps:

step 1, determining the number and position distribution of blast holes of one-time blasting according to blasting design, drilling holes in a slope rock body containing deep cracks, and obtaining the number and position distribution of the blast holes with interconnected joint cracks by comparing the drilling speed of the rock body in the holes and the hole and the gas overflow phenomenon;

step 2, aiming at the situation that the blast hole penetrates through the fracture area, dividing a blast hole charging section penetrating through the fracture area into a lower coupling charging section, a fracture area weakening charging section and an upper conventional charging section according to the position distribution of the fracture area in the blast hole;

step 3, carrying out blast hole charging, namely firstly scratching an explosive packaging bag, slowly placing the explosive packaging bag at the bottom of a blast hole, extruding the explosive packaging bag by using a charging rod to form a lower coupled charging section, arranging a primary blasting cap on the lower coupled charging section, then binding a small-diameter cartridge on bamboo chips or wood chips, slowly feeding the cartridge into the blast hole, filling the radial interval between the cartridge and the blast hole by using rock debris to form a fracture area weakening charging section, and finally charging according to a conventional method to form an upper conventional charging section; conventionally charging the rest blast holes;

step 4, blast hole blocking is carried out according to blasting design;

and 5, networking and detonating, namely based on the principle that the first-time blasting hole creates a blank surface for the second-time blasting hole, combining the position distribution of the blasting holes with the joint fractures communicated with each other, sectionally networking and detonating the blasting holes with the joint fractures communicated with each other in a segmented manner, conventionally networking and detonating the rest blasting holes, wherein each hole is detonated by using a hole bottom.

Furthermore, the particle size of rock debris filled in the radial interval between the explosive roll of the weakening charge section in the fracture area and the blast hole wall is 0.1-8.0 mm.

Further, the diameter of the cartridge of the weakened charging section in the fracture area is 20-40 mm smaller than that of the cartridge of the conventional charging section at the upper part.

The invention has the beneficial effects that: according to the invention, sectional charging is adopted on the charging structure, and rock debris is used for filling the interval between the explosive roll and the blast hole wall in the weakened charging section of the fracture area, so that the explosive gas can be prevented from leaking too early through the joint fracture, the pressure peak value and the duration time of the explosive gas can be improved, and the 'gas wedge' effect of the explosive gas can be fully exerted; the blast holes with the joint fractures communicated with each other are subjected to grouping networking initiation, so that the condition that the blast holes are initiated firstly and then are initiated secondly through the joint fractures can be avoided, and the occurrence of misfiring accidents is avoided. The method is efficient, practical, safe, reliable and convenient to operate.

Drawings

FIG. 1 is a schematic view of the construction process of the present invention; in fig. 1, (a), (b), (c) and (d) are schematic cross-sectional states of the blast hole after the operation is finished by a lower coupling charge section, a fracture zone weakening charge section, an upper conventional charge section and a blocking section in sequence;

in the figure: 1-detonator with detonating tube, 2-lower coupled charge section, 3-bamboo chip, 4-weakened charge section in fracture zone, 5-upper conventional charge section and 6-blocking section.

FIG. 2 is a schematic diagram of a zonal blasting initiation network;

in the figure: 8 blast holes in the dotted line frame are the blast holes with joint fractures communicated with each other, and the rest blast holes are the more complete blast holes of the adjacent rock mass; the blast holes are divided into A, B, C, D rows transversely and 1, 2, 3, 4, 5, 6, 7 and 8 columns longitudinally, wherein the icon I represents the blast holes, the icon II represents the detonator, and the icon III represents the detonator.

Detailed Description

The present invention is further described below in conjunction with the following detailed description, which is intended to further illustrate the principles of the invention and is not intended to limit the invention in any way, but is equivalent or analogous to the present invention without departing from its scope.

With reference to the attached drawings.

The deep hole bench blasting method is adopted for blasting a certain open cut stone, the height of the bench is 8.0m, the ultra-depth is 0.8m, the drilling inclination angle is 90 degrees, the depth of blast holes is 8.8m, the diameter of the blast holes is 90mm, the holes are distributed in a rectangular shape, the blast holes are divided into 4 rows, each row is 8, the row spacing is 3.0 multiplied by 2.5m, the explosive adopts rock emulsion explosive II, the diameter of the explosive roll of the upper conventional loading section is 70mm, the diameter of the explosive roll of the fracture zone weakening loading section is 32mm, the length of the loading section is 6.3m, the length of the blocking section is 2.5m, and the specific implementation steps are as follows:

(1) and (6) drilling. Drilling holes in the slope rock body to be blasted and excavated, and in the drilling process, comparing the drilling speed of the rock body in the hole and the gas overflow phenomenon to obtain the number and the position distribution of blast holes with joint fractures communicated with each other. In this embodiment, the number of the blastholes with joint fractures communicated with each other is 8, that is, B, C two rows of No. 3 to No. 6 blastholes, in this embodiment, the subsequent operations are performed by taking the distribution of the positions of the fracture regions in the blastholes of number B3 as an example, the top of the fracture region in the blastholes of number B3 is located 4.2m above the bottom of the hole, and the bottom of the fracture region is located 2.2m above the bottom of the hole, which is a schematic diagram of a construction flow drawn by taking the blastholes as an example in fig. 1.

(2) The charge segment is segmented. Based on the position distribution of the fracture area in the blast hole, dividing a blast hole charging section into a lower coupling charging section, a fracture area weakening charging section and an upper conventional charging section, wherein the length of the lower coupling charging section is 2.0m, the length of the fracture area weakening charging section is 2.4m, and the length of the upper conventional charging section is 1.9 m;

(3) and (5) charging the blast hole. For the lower explosive loading section, the explosive packaging bag is cut, the coupling rate is controlled, the explosive is extruded by the explosive loading rod, the explosive is tightly contacted with the blast hole wall to form the lower coupled explosive loading section, and a primary explosive MS11 detonating tube detonator is arranged in the explosive; binding a cartridge with the diameter of 32mm on a bamboo chip for a loading section in a fracture area, slowly feeding the cartridge into a blast hole, and filling a radial interval between the cartridge and the blast hole with rock debris with the particle size of 0.1-8 mm to form a weakening loading section in the fracture area; for the upper explosive-filled section, the upper conventional explosive-filled section is formed by charging according to the conventional method, and the diameter of the explosive cartridge is 70 mm;

(4) and (4) blocking. The length of the plugged section is 2.5m, and blast holes are plugged according to a conventional method;

(5) networking and detonating. Based on the principle that a first-explosion blast hole creates a blank surface for a second-explosion blast hole, blast holes with interconnected joint fractures are subjected to sectional networking initiation in a sectionalized manner by combining the position distribution of the blast holes with interconnected joint fractures, and other blast holes are subjected to conventional networking initiation, wherein fig. 2 is a schematic diagram of a sectionalized blasting initiation network.

By applying the method for blasting and excavating the deep crack side slope rock mass, provided by the invention, the blasting area is checked after the blasting work is finished and the safety is confirmed, so that the bottom of the step basically has no root, and the mass percentage after blasting is lower.

By applying the method for blasting and excavating the rock mass with the deep crack side slope, blasting holes of all sections are detonated according to a blasting circuit in the blasting process, no misfiring accident occurs, the blasting area is checked and found after the blasting work is finished and the safety is confirmed, the bottom of the step basically has no root, the mass percentage is low after blasting, and the blasting effect is good. And because the explosive is loaded in sections, the weakened explosive loading sections in the crack area are filled, so that the unit consumption of the explosive is reduced, and the explosive consumption is reduced.

Claims

1. A blasting excavation method for deep crack containing slope rock mass is characterized by comprising the following steps:

step 1, according to blasting design, determining the number and position distribution of blast holes for blasting, drilling holes in a slope rock mass with deep cracks, and comparing the drilling speed of the rock mass in the holes and the gas overflow phenomenon to obtain the number and position distribution of the blast holes with interconnected joint cracks;

step 2, aiming at the situation that the blast hole penetrates through the fracture area, dividing the blast hole charging section penetrating through the fracture area into a lower coupled charging section, a fracture area weakened charging section and an upper conventional charging section according to the position distribution of the fracture area in the blast hole;

step 4, blast hole blocking is carried out according to blasting design;

2. The blasting excavation method of the deep crack containing slope rock mass according to claim 1, characterized in that: and the fracture area weakens the explosive loading section, and the particle size of rock debris filled in the radial interval between the explosive cartridge and the blast hole wall is 0.1-8.0 mm.

3. The blasting excavation method of the deep crack containing slope rock mass according to claim 1, characterized in that: the diameter of the cartridge in the weakening charging section in the fracture area is 20-40 mm smaller than that of the cartridge in the conventional charging section at the upper part.