KR20020069330A - NATM omitted - Google Patents

Abstract

PURPOSE: An NATM using a probe large hole burn out bedrock classification system is provided to restrain the damage of the in-situ ground maximally, to reduce explosives by preventing overcharge and to improve blasting and digging efficiencies. CONSTITUTION: The NATM(New Austrian Tunneling method) using a probe large hole burn out bedrock classification system comprises the steps of: dividing the section of a tunnel into a large hole part(1) and a perimeter part(2), then boring; charging the large hole part(1), then blasting; and tunneling by utilizing the extended state of a plastic region occurring on the perimeter part(2) by the blasting result of the large hole part(1) for measurement.

Description

NATM excavation using advanced blast rock mass classification

According to the present invention, when a tunnel is excavated by NATM (New Austrian Tunnelling Method) method, it is possible to maintain the stability of the tunnel by restraining damage to the surrounding ground due to the blast as much as possible. The present invention relates to a method for estimating the displacement of rock mass around the membrane caused by blasting.

The design concept of NATM is preliminary design, preliminary design, indeterminate design, or feed back design. The design method is based on statistical concept and physical formula.

However, the classification factors that determine the support pattern and the blasting pattern designed by this design concept are quite different from the actual tunnel rock bed state. In order to overcome this difference, the results measured at the excavation membrane should be fed back to the construction stage. However, the conventional rock classification method is mainly used by the RMR method developed by Beniawski between 1972 and 1973. However, this method classifies the rock into several factors and adds the number assigned to each factor. You get

This RMR value has a value between 0 and 100 and is thus divided into five grades. The grade and RMR values determine the independence time and reinforcement methods for the tunnels excavated in the rock. However, this method is not only available to those who have the ability to convert things into numerical values, but also differs greatly depending on the person handling, causing problems in trust.

In addition, the plastic zone expansion phenomenon due to blasting of surrounding ground is almost unpredictable. In general, the construction site applies a uniform blasting design pattern according to the design support pattern. This result causes overcasting or collapse, which adversely affects the stability of the tunnel, resulting in shortening of tunnel life.

The present invention provides an excavated cross-sectional segmentation method of the advanced blasting method of the heart-breaking blasting method that can accurately measure the expansion and displacement of the plastic zone caused by the blasting to solve the above problems. There is an object of the invention.

Another object of the present invention is a method of measuring the displacement of the surrounding rock by blasting the cardiac portion 1 first of the divided section, and the result is determined by the dose determination for blasting the peripheral portion 2 and the periphery 2 blasting. It is to provide a method of perforation and remedy that can prevent ground damage.

Still another object of the present invention is to minimize the damage to the periphery of the excavation field of the advanced lead portion of the heart, while the maximum support interval (low speed excavation) (3), two support interval (high speed excavation) (4), and three support of the design support pattern By determining the interval (rapid excavation) (4) to provide a way to improve the drilling efficiency and to adjust the work cycle.

1A is a cross sectional view of an advanced cardiac segmentation and digging site

Figure 1b is a cross-sectional view of the mining relaxation measurement method of the heart attack advanced breakthrough results

Figure 2a is a deep blast 2 support section (high speed excavation) blasting pattern one embodiment

Figure 2b is a puncture and heart portion by the blasting pattern of Figure 2a diagram

FIG. 2C is a diagram illustrating the peripheral portion of the first support section adjusted after the blasting of the heart portion by the blasting pattern of FIG.

FIG. 2D is a schematic diagram of the peripheral portion of the second support section adjusted after the blasting of the heart section and the first support section by the blasting pattern of FIG.

Table 1a is the design dose table according to the blasting pattern of Figure 2a

Table 1B is a dosage table of the adjusted one embodiment of FIGS. 2B, 2C, and 2D.

<Explanation of symbols on the main parts of the drawing)

1: Heart part 2: Peripheral part

3: Heart advance advanced 1 support section (slow speed excavation) 4: Heart advance advanced 2 support section (high speed excavation)

5: heart advances 3 jibo section (rapid excavation) 6: heart weakening outer ship

7: Top portion loosening width 8: Left side wall loosening width

9: Right side wall part relaxation width 10: Excavation membrane relaxation width

11: heart hair mill cloth factory

Hereinafter, described in detail by the accompanying drawings as follows.

In general, the support interval by type of NATM is designed as follows.

6 Type: 1.0 m (steel support), 5 Type: 1.2 m (steel support),

4Type: 1.5 m (steel support), 3Type: 2.0 m (solid support)

2Type: 2.5 m (Muzibo), 1Type: 3.5 m (Muzibo)

Figure 1a (a) is a cross-sectional view showing the Tunnel splitting excavation method of the present invention (1) is the heart portion can fully exert the heart blasting effect and the mining relaxation area caused by this cross-sectional blasting rock around the Tunnel The 4m × 4m range without affecting the damage is determined by the divided section of the core.

Figure 1a (b) is a longitudinal cross-sectional view showing the tunneling excavation method of the present invention (3) is one support section (low speed excavation), (4) two support section (high speed excavation), (5) is three support Interval (rapid excavation) shows a deep-dive advanced rig.

At this time, the method of Feed Back Determination of Heart Rig Excavation is performed by drilling the entire membrane length by the perforation pattern designed for each support pattern of each excavation pattern. Determined by the result.

If this is expressed as a formula, mining relaxation index In detail, this determination method is illustrated in FIG. 1B. If there is a portion where the relaxation area of the heart extraction area is wider than the fabric factory 11 from the heart ridge line 6, only one support section should be advanced. In this case, the independence of the surrounding rock is a problem, so be sure to review the implementation of the supplementary methods and the change of support and blast patterns.

However, when the cardiac mining relaxation region extends less than the fabric mill 11 from the cardiac periphery of the medicinal vessel (6), the second support section is advanced. In addition, if the mining area of the heart extraction area extends from the outer ledge line 6 less than half of the fabrication plant, the three-pronged section is drilled in advance. Review.

Therefore, if this is explained by substituting this into the formula,

1) If the mining relaxation index is 1 or more, the upward change of the fast drilling should be considered, the high speed drilling should be a low speed drilling, and the low speed drilling should be considered an upward change.

2) The mining relaxation index remains between 1 and 0.5 in the current way.

3) If mining relaxation index is between 0.5 and 0.3, the countermeasure of 1) shall be taken.

4) If the mining relaxation index is less than 0.3, the downward change or non-support of the Pattern should be considered.

Since the present invention blasts the heart part first, the advanced blasting result of the heart part is shown by reducing the state of relaxation of the surrounding rock and the behavior of the membrane and the surrounding rock due to the blasting effect. Therefore, anyone can judge the damage right of the periphery blast to the tunnel base by visual measurement and feed back the advanced blasting result of the core part and use it to change or adjust the design pattern of the periphery and the next curtain and the blasting pattern.

In particular, the matters to be noted when applying the present invention to the construction must be perforated with the periphery of the periphery (2) 1 support when drilling the heart hair (1). The reason is that when the blasting the heart part 1 due to the joint development or weakening of the rock, the peripheral part 2 armed balls block the expansion of the plastic area due to the blasting shock and the plastic area is expanded. . In addition, as a result of visual observation and drilling, the drilling zone is tightly intersected between the outer periphery in the direction in which the wreckage, rescue team, weathering zone, and soft arm are detected to block the expansion of the plastic zone.

One embodiment in which the excavation method of the present invention is applied to the construction of a railway tunnel is described in detail with reference to the accompanying drawings. FIG. 2A is a maximum delay considering the civil complaint of a private house located at a 200 m point in a shaft as shown in Table 1A. This is a blasting pattern designed to limit the dosage to 0.88Kg. This design dose is 104.6㎥ (52.3 × 2) excavation, 78.69Kg (28.24 + 25.225 × 2), and 0.752Kg / ㎥ (78.69 / 104.6) specific dose. have.

However, in the application process of the present invention, as shown in FIG. 2B, since the support pattern is 6 type, the core hair part is perforated according to the perforation pattern of FIG. It was.

The results of this blasting are explained by FIG. 1B, and the mining relaxation was relaxed up to 1.0m for the left wall, up to 0.8m for the right wall, and up to 1.8m for the top wall at the boundary of the heart-loading line 6. . The loosening index of this blasting is 2m in the mill and the maximum relaxation width is 1.8m in the upper half, so it is 0.9 based on this. Therefore, it can be excavated by the current method without changing the blast pattern. This site has already been constructed with the Fore Pilling method as a secondary stabilization ball, so the second blasting drills 10 additional armored holes between the outer holes to block the expansion of the plastic area, as shown in Figure 2c. As a result of blasting by adjusting one hole per two holes to armed medicine, blasting efficiency achieved 100% without loosening of the ground. The blasting around the 3rd secondary support section was controlled blasting as shown in FIG. 2D based on the 2nd blasting result.

Comparing the test blasting results of the present invention as described above with the blasting design shown in FIGS. 2A and 1B, the heart blasting part is the same as the design, but the peripheral secondary and third blastings feed back the blasting blasting result to adjust the puncture and charge amount. The savings of splenic dose 0.559kg / ㎥ (58.53 / 104.6) and 49 used primers (38 + 82 × 2) -153] were obtained. In general, the blasting at the tunnel construction site blasts the excavation section based on the design pattern at one time, eliminating the testing process for the blasting results. Blasting This causes the loosening of the base around the tunnel and becomes an uneconomical construction, and it is clear that the present invention is a method to improve this.

As described above, in the present invention, the excavation cross-section of the excavation cross-section in the method of accurately visually measuring the expansion and displacement of the plastic region derived from blasting on the rock to be excavated to the excavation target rock part 1 and the peripheral part 2 By dividing the cross section into blasts, blasting the core part first and measuring this blasting result to feed back the periphery and the next membrane perforation pattern and the refilling method, thereby achieving standard blasting to prevent loosening of the ground and stable tunnel construction and prolong the service life. do. In particular, the measuring method proposed by the present invention is an easy method that anyone can make an accurate judgment easily, so the applicability is good.

In addition, the present invention is the (low speed excavation) to make the one excavation length of the heart portion 1 as one support section (3), (high speed excavation) to make the two support section (4) and the three support section (5) By presenting a method of stably determining (rapid drilling), the working cycle can be adjusted and the drilling efficiency is improved.

In addition, the present invention can be applied to both the shear surface excavation method and the split-section excavation method, and when the first excavation chapter of the heart is applied to the 2 and 3 support sections, the detonation primer of the heart is reduced and the exaggeration of the peripheral part is reduced. Since it is prevented, the construction cost due to the reduction of explosives is reduced.

Claims (3)

As a method of predicting displacement of the surrounding rock due to blasting in order to actively utilize the bearing capacity of the surrounding rock by restraining the relaxation of the surrounding ground due to blasting when excavating the tunnel. 1) drilling the cross section by dividing the excavated cross section into the core 1 and the periphery 2 2) blasting by first charging the heart part (1) of the divided section 3) Excavation method characterized in that the excavation of the tunnel by utilizing the expanded state of the plastic region generated in the peripheral portion (2) as a result of the blasting of the heart portion (1) for measurement. The control method according to claim 1, wherein the measurement result is fed back to the peripheral part (2) and the support and the charge pattern determination for the next film blasting. According to the measurement result of claim 1, the first advanced excavation site of the core part 1 of the following membrane excavation is 1) 1 support section (3): low speed excavation 2) 2 support section (4): high speed excavation 3) 3 support section (5): rapid drilling Determination method characterized in that the feed back to determine the working pattern and cycle.