CN103322872B - A kind of method improving Long-hole Bench Blasting vibration frequency - Google Patents

Abstract

The invention discloses a method for increasing the vibration frequency of deep-hole step blasting, which comprises steps in sequence: step 1, laying blast holes according to blasting requirements; step 2, completing the charge structure in the blast holes; step 3, placing the charge section, etc. It is divided into N detonation sections, N≥1, and the detonation point is set at the midpoint of each detonation section, and the length of the detonation section is not less than twice the damage radius; step 4, detonation is carried out by using the nonel detonation method. The method of the invention can increase the blasting vibration frequency of the rock mass within the range of 20 to 110 meters around the blast source, thereby reducing the damage degree of the rock mass, more fully avoiding the natural vibration frequency of adjacent buildings (structures), and avoiding the explosion of adjacent buildings (structures). The blasting dynamic instability caused by resonance of buildings can be used for drilling and blasting excavation construction in geotechnical engineering fields such as water conservancy and hydropower, mining and transportation.

Description

A Method of Raising the Vibration Frequency of Deep Hole Bench Blasting

technical field

The invention belongs to the fields of geotechnical engineering such as water conservancy and hydropower, mining and transportation, and relates to a method for increasing the vibration frequency of deep-hole step blasting.

Background technique

In order to improve drilling and blasting efficiency, large-scale rock mass excavation and stockyard mining generally adopt deep hole bench blasting. The blasting vibration induced by deep hole blasting has higher peak velocity and lower frequency than shallow hole blasting. Previous studies have shown that blasting vibration frequency has an important impact on rock mass damage and the safety of adjacent buildings (structures): the lower the vibration frequency, the greater the impact of blasting vibration. For rock drilling and blasting, the number and location of blasting points are one of the important factors affecting the blasting vibration frequency. Traditional detonation technology does not consider the active control of blasting vibration frequency.

Contents of the invention

The object of the present invention is to provide a method for increasing the blasting vibration frequency of deep hole steps, so as to avoid rock mass damage and blasting vibration dynamic instability caused by low blasting vibration frequency.

To achieve the above object, the present invention adopts the following technical solutions:

A method for increasing the vibration frequency of deep hole step blasting, comprising the steps in sequence:

Step 1, deploy blast holes according to blasting requirements;

Step 2, completing the charge structure in the blast hole;

Step 3, dividing the charging section into N detonation sections, N≥1, respectively setting detonation points at the midpoints of each detonation section, and the length of the detonation section is not less than twice the damage radius;

In step 4, detonation is carried out by using a nonel detonation method.

The described adopting nonel detonating method to detonate is specifically:

A detonator is used to detonate the detonator.

In order to ensure simultaneous detonation of each detonation point in the same blasthole, the same section of detonator should be used to detonate each detonation point in the same blasthole.

Compared with prior art, the present invention has following characteristics:

1. The present invention proposes a new detonation technology, which does not change the drilling and blasting process and parameters, divides the charge section into N detonation sections (N≥1), and sets the detonation point at the midpoint of each detonation section. It can increase the blasting vibration frequency of the rock mass within 20-110 meters around the explosion source to varying degrees, thereby reducing the degree of damage to the rock mass, more fully avoiding the natural vibration frequency of adjacent buildings (structures), and avoiding the explosion of adjacent buildings (structures). Blasting power instability caused by material resonance.

2. According to the safety criterion of blasting vibration based on the frequency-vibration speed dual factor, the method of the present invention can increase the safe permissible vibration speed of adjacent building (structure) material points, reduce the difficulty of blasting vibration control, and reduce engineering investment.

3. The present invention can be used to increase the vibration frequency of large-scale deep hole blasting, and is widely used in drilling and blasting excavation construction in geotechnical engineering fields such as water conservancy and hydropower, mining and transportation.

Description of drawings

Figure 1 is a schematic diagram of the explosion in the middle;

Figure 2 is a schematic diagram of two-point detonation;

Figure 3 is a schematic diagram of three-point detonation;

Fig. 4 is the relationship curve between blasting main vibration frequency and detonation center distance under different detonation modes;

Fig. 5 is the relationship curve between blasting vibration centroid frequency and detonation center distance under different detonation modes.

In the figure, 1-detonator; 2-blocking section; 3-rock mass; 4-nonel; 5-detonation point; 6-charging section; 7-air.

Detailed ways

The invention improves the position and quantity of the detonation point, divides the charging section into N detonation sections (N≥1), and sets the detonation point at the midpoint of each detonation section.

Several specific implementations of the present invention will be further described below in conjunction with the accompanying drawings.

See Figure 1, which is a schematic diagram of the initiation of the middle part, that is, the initiation method in the case of N=1. On the premise of ensuring the blasting fragmentation effect, the initiation point is set at the middle point of the charge section.

See Figure 2, which is a schematic diagram of two-point initiation, that is, the initiation method in the case of N=2. On the premise of ensuring the blasting fragmentation effect, the charge section is divided into two initiation sections, and the two initiation points are respectively set in each initiation section. midpoint.

See Figure 3, which is a schematic diagram of three-point initiation. Under the premise of ensuring the blasting fragmentation effect, the charge section is divided into three initiation sections, and the three initiation points are respectively set at the midpoint of each initiation section.

The application of the inventive method should pay attention to the following points:

1) The selection of the location and number of initiation points should comprehensively consider the effect of increasing the blasting vibration frequency, economic and construction factors, and reasonably control the length of each initiation section.

2) The detonation point is set at the midpoint of each detonation section of the charge section. In order to achieve simultaneous detonation of each detonation point in the same blast hole, each detonation point should be detonated by the same detonator.

3) The dynamic finite element numerical simulation results show that the blasting vibration frequency can be increased by 10% to 35% if the length of the initiation section is properly controlled.

Specific application examples of the method of the present invention will be described below.

For stone mining in a granite quarry, the blasting design requirements are: blasthole depth 18m, blasthole diameter 150mm, charge diameter 130mm, block length 3.0m, and continuous charge structure.

Adopt middle part detonation for this embodiment, concrete steps are:

1. According to the above design requirements, the blastholes are arranged.

2. According to the above-mentioned design requirements, complete the charge structure in the blast hole that has passed the acceptance test. Then, set the detonation point at the middle point of the charge section. In this embodiment, the charge section is 15m, and then the detonation point is set at the middle distance of the blast hole. The 7.5m position at the bottom of the blast hole.

3. Use the detonator detonation method to detonate, specifically: use a detonator to detonate the detonator, and use a non-electric detonator to stimulate the detonation of the detonator outside the blast hole. After the detonator is excited, a shock wave is generated in the tube and transmitted to the detonator. Tap to detonate the explosives.

Dynamic finite element numerical simulation is used to simulate the detonation method of this embodiment and the reverse detonation method of traditional deep hole step blasting to obtain the relationship curve between the blasting main vibration frequency and the detonation center distance, and the relationship curve between the blasting vibration centroid frequency and the detonation center distance, as shown in Figure 4 ~5. It can be seen from Figures 4 to 5 that within the range of 20 to 110 meters from the blast center, the blasting main vibration frequency of the central blasting increases by 17.9% on average, and the blasting vibration centroid frequency increases by 13.2% on average. the

Adopt two-point detonation for this embodiment, concrete steps are:

1. According to the above design requirements, the blast holes are arranged.

2. According to the above-mentioned design requirements, the charge structure is completed in the blast hole that has passed the acceptance test. Then, two points of detonation are adopted. In this embodiment, the charge section is 15m. m and 11.25m positions.

3. The nonel detonation system is used for detonation, specifically: the detonator is used to detonate the nonel, and the direction of the detonator's energy-gathering hole should be opposite to the detonator's detonation direction.

Dynamic finite element numerical simulation is used to simulate the detonation method of this embodiment and the reverse detonation method of traditional deep hole step blasting to obtain the relationship curve between the blasting main vibration frequency and the detonation center distance, and the relationship curve between the blasting vibration centroid frequency and the detonation center distance, as shown in Figure 4 ~5. It can be seen from Figures 4 to 5 that within the range of 20 to 110 meters from the blast center, the blasting main vibration frequency of two-point initiation increases by an average of 30.2%, and the blasting vibration centroid frequency increases by an average of 21%.

According to my country's "Blasting Safety Regulations" (GB6722-201x), the blasting vibration safety criterion not only considers the peak value of blasting vibration velocity, but also includes the impact of blasting vibration frequency on ground buildings, tunnels, slopes and other structures. . It can be seen from Table 1 that increasing the blasting vibration frequency can increase the blasting vibration velocity in the corresponding frequency range.

Table 1 Relationship between blasting vibration frequency and blasting vibration velocity in the corresponding frequency range

Based on the above frequency-vibration speed dual-factor blasting vibration safety criterion, the present invention can increase the safe permissible vibration speed of adjacent building (structure) material points, reduce the difficulty of blasting vibration control, and reduce engineering investment.

Claims (3)

1. A method for improving the vibration frequency of deep-hole step blasting, comprising the steps of: according to design requirements, arranging blastholes, completing charge structure, detonation point setting and detonation in blastholes, characterized in that: The setting of the detonation point is specifically: Divide the charging section into N detonation sections, N>1, respectively set the detonation point at the midpoint of each detonation section, and the length of the detonation section is not less than twice the damage radius. 2. the method for improving deep hole step blasting vibration frequency as claimed in claim 1, is characterized in that: The described detonation adopts the nonel detonation method. 3. the method for improving deep hole step blasting vibration frequency as claimed in claim 2, is characterized in that: Each detonation point in the same blast hole is detonated by the same section of detonator.