JPS637490A - Method of consolidation construction of base rock - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a rock consolidation method for improving soft or crushed rock to a solid rock using a rock consolidation chemical.

[Conventional technology]

Conventionally, in geological zones such as soft rock (other mountains) or crushed ground, in order to prevent the top of the tunnel face from collapsing, etc., there is a wall at the top of the tunnel face along the arch of the top. Countermeasures are taken to strengthen the ground, such as the advance bolt method, in which a hole is drilled and a rock bolt is inserted into the hole, or the bolt is solidified with mortar, the vibration roof method, and the chemical injection method. things are being done. However, with this conventional method, there are disadvantages such as major damage to equipment, time-consuming installation of machines and preparation for injection, and the need to stop work at the site for a considerable period of time for these operations. was occurring.

[Problem that the invention seeks to solve]

Therefore, in order to solve these difficulties, the present inventors provided a packing (sealing material) such as cloth on one end side of a backer made of a hollow pipe, and filled the packing with foamed resin such as urethane resin. After impregnation, the backer is inserted from the other end into a hole previously drilled in the other thread, and in this state, the urethane resin impregnated into the packing is cured to form a foam layer around the backer. The opening of the hole is closed, and then a urethane resin or the like is press-fitted into the backer to fill the gap between the backer and the hole wall, and at the same time, the urethane resin is allowed to penetrate into the ground and harden, thereby placing the backer inside the hole. A patent application has already been filed (Japanese Patent Application No. 144024/1982) for a method of solidifying the rock around the hole while leaving it intact.In other words, the above method (hereinafter referred to as the "conventional method") is As shown in the figure and FIG. 16, backers 30 are inserted into holes that are diagonally upwardly bored at predetermined intervals along the arch of the ceiling in the ceiling section 29 at the tip of the tunnel face.
is inserted and the opening of the hole is closed with the gasket 31 at the base, and in this state, the two-component foamed urethane resin supplied from the hose 33 equipped with the connection unit 32 is discharged from the tip of the backer 30. This method solidifies the rock by filling the holes with urethane resin and then infiltrating the urethane resin into the ground as shown in the figure and hardening it.

In the figure, 34 is the shoring, and 35 is the consolidation area. The tunnel is formed by solidifying the top plate 29 at the tip of the tunnel face with a hardened resin along the arch of the top plate, and in this state, excavating the tip of the tunnel face. After excavating a certain distance, The process of solidifying the top plate portion 29 is repeated. In this case, according to the conventional method, the top plate portion 29 is consolidated by both the backer 30 left in the hole and the consolidated area 35 distributed around it, as shown in FIG. Extremely strong consolidation is achieved. Furthermore, since no large machinery is required for construction, there is no need for costly equipment, and because the consolidation is done with hour wheels, there is an advantage that interruptions in on-site work can be minimized in an extremely short period of time.

However, in the above construction method, the two-component foamed urethane resin used is a urethane resin that takes 3 to 5 minutes to harden after mixing the two components.
When 0 is inserted and urethane resin is press-fitted, it takes time for the resin that penetrates into other mountains to harden, and the area where the resin penetrates becomes thicker (as shown in Figure 15). When excavating, the part indicated by A in Figure 15 is removed by excavation, and not only is the resin in this part wasted, but the rock in this part is consolidated and hard. However, it has the disadvantage that excavation is time-consuming.In addition, as mentioned above, resin immersion i3'
The BJI region is thick (as a result, the amount of resin used increases and the resin press-fitting time also increases. In other words, when press-fitting the urethane resin into the backer 30, the urethane resin discharged from the tip of the backer 30 is When the urethane resin penetrates into the mountain and hardens, the pressure required for press-fitting the resin suddenly increases, so this is used as a guide to stop press-fitting the resin.The longer the curing time of the urethane resin used, the more the resin liquid As the amount of press-in increases, the permeation area becomes larger, and as mentioned above, wasteful permeation occurs, and the press-in time and amount of resin liquid used increase. In order to do this, the upward inclination angle of the backer can be increased to make the resin infiltration area tilt upward.This will reduce the wasted infiltration area A.However, due to the support of the pressure of the ground, For this reason, it is more effective to reduce the slope angle of the permeable area to make it as close to horizontal as possible.As mentioned above, increasing the slope upward will effectively support the pressure of the ground. Therefore, taking these into consideration, the limit of the upward inclination of the backer 30 is 25 to 3'0° as shown in Fig. 16, but at this inclination angle, unnecessary penetration occurs. Part A is generated.Furthermore, when press-fitting the urethane resin, the work is complicated because the packing 31 must be attached to the backer 30 one by one.Furthermore, in the conventional rock consolidation method, the curing time is short. Because a long chemical solution is used, it is sometimes unavoidable that the chemical solution leaks through the ground to the front of the face, and it is necessary to treat the concrete spraying on the top surface before consolidation, which takes time. There are some difficulties.

The present invention was made in view of the above circumstances, and aims to prevent the generation of wasteful parts in the resin permeation area, shorten the construction time, reduce the amount of resin used, and streamline the construction work.

[Means for solving problems]

In order to achieve the above object, the rock consolidation method of the present invention involves drilling a hole in the ceiling at the tip of the tunnel face so as to extend in the tunnel excavation direction, and in this hole, there is a chemical discharge hole on the tip side. Position the rock bolt with the rock bolt inserted all the way to the base, pressurize the rock solidification chemical into the rock bolt, fill the hole with the rock solidification chemical, allow it to penetrate into the rock, and press the rock solidification chemical into the rock bolt. A method of solidifying rock by hardening a chemical solution for rock solidification that fills the hole and penetrates the rock, with the rock bolt remaining in the hole, the rock bolt is used to excavate a tunnel on the ceiling surface of the roof section. Based on the direction extension surface, the center axis of the lock bolt is 1 point with respect to the above extension surface.
It is tilted upward at an angle of 0 to 20 degrees, and a fast-curing two-component foamed urethane resin is used as the rock solidification chemical.

In other words, as a result of further research in order to eliminate the drawbacks of the above-mentioned conventional method that the present inventors had proposed earlier, the inventors found that conventionally, when using a resin that has an extremely fast curing speed, it is difficult to cure the resin in a hollow pipe such as a packer. When using a special two-component foamed urethane resin with a fast curing speed, which was considered impossible to use due to curing, the diameter of the resin permeation area that is formed in a cylindrical shape around hollow pipes such as packers can be reduced. Therefore, it has been found that the wasted portion A (see FIG. 15), which was conventionally required, is significantly reduced, and at the same time, the construction time and the amount of resin used can be significantly reduced. Then, when the resin is discharged from the tip of the hollow pipe and flows down near the opening of the hole, it hardens exactly and closes the opening of the hole. Therefore, as in the conventional method, a packing etc. is attached to the packer in advance. There is no need for complicated work such as closing hole openings to prevent resin from leaking, and concrete spraying can solidify the rock without any treatment even on soft ground such as sand. We discovered this and arrived at this invention.

This invention uses a fast-curing two-component foamed urethane resin,
This is press-fitted into a rock bolt inserted into a hole drilled in the rock to perform "rock consolidation."

As the above-mentioned fast-curing two-component foamed urethane resin, for example, one that uses the following components A and B at a mixing ratio of 1:1 and has an extremely short curing time of 5 to 30 seconds after mixing the two components. Awarded. The above liquid A is a mixed liquid mainly composed of a primary polyol having two or more hydroxyl groups, and has a hydroxyl value of 250 to 450.
It is composed of KOHmg/g polyol liquid. Such polyol liquid usually has a hydroxyl value of 20 to 640.
0 Kojimg/g, average molecular weight 18-5000 and 2
It is prepared by using a combination of several types of primary and secondary polyols having higher functionality. In addition, the above B liquid contains diphenylmethane-4,4'-diisocyanate (MDI), polymeric polyphenyl polyisocyanate (polymeric MDI, crude M) having two or more isocyanate groups.
DI) and tolylene diisocyanate (TDI) with an average molecular weight of 174 to 2000.
．． Contains isocyanate groups! 18-48% by weight (hereinafter “
%) isocyanate liquid.

To explain in more detail, the polyol components of the liquid A include polypropylene glycol, polyethylene glycol, trimethylolethane, trimethylolpropane, and hexylene glycol.

Examples include alkylene glycols such as castor oil. In addition, ethylene oxide and propylene oxide are added to glycerin, sorbitol, or sucrose, as well as ethylene oxide-propylene oxide copolymers, and amines such as ethylene diamine, jetanolamine, triethanolamine, and triethylene diamine. Examples include reactants to which propylene oxide is added. Particularly suitable are the following polyols.

(1) Low molecular weight (molecular weight 60-1000) such as ethylene glycol, diethylene glycol, triethylene glycol, dipropylene glycol, low viscosity (500 cps)
/ 25℃ or below), bifunctional or higher, and a hydroxyl value of 50 to 2
000 gOHmg/g alkylene glycol.

(2) Glycerin, sucrose added with ethylene oxide and propylene oxide, with a molecular weight of 500 to 6,000.
A bifunctional or higher functional polyol with a hydroxyl value of 20 to 1000 KOHmg/g.

(3) Ethylenediamine, triethanolamine,
Triethylene diamine with ethylene oxide and propylene oxide added, molecular weight 100 to so o
o, a bifunctional or more functional polyol with a hydroxyl value of 20 to 1000 KOHmg/g.

The isocyanate components of liquid B include polymeric MDI with an isocyanate group content of 30 to 31.5%, a dimer of highly reactive diphenylmethane-4,4°-diisocyanate (isocyanate group content of 32 to 34%), Trimeric formulations and crude MDI with low molecular weight (50~
1000) polyols, such as ethylene glycol,
Examples include reaction products with diethylene glycol, dipropylene glycol, etc. (isocyanate group content 20 to 30%), dimers of the diphenylmethane-4,4°-diisocyanate, and reaction products of the trikeidome with the above low molecular weight polyols. .

The polyol component of the liquid A has a primary hydroxyl group, and its reactivity with isocyanate groups is very fast and active, but a catalyst may be added to further speed up the reaction rate. Examples of catalysts include ethylenediamine, triethylenediamine, triethylamine, ethanolamine,
Aliphatic amines such as jetanolamine and dimethylethanolamine, aromatic amines such as 4,4'-diaminodiphenylmethane, and organic amines such as dibutyltin dilaurate, tin octylate, tin chloride, lead octenoate, and lead naphthenate. It can be used in combination with a metal catalyst. In addition, the expansion ratio of urethane resin foam can be improved by using trichloromonofluoromethane CCC13F), methylene chloride (CzH
4CI! Although it is possible to use an inert solvent such as z), pentane, or water, it is preferable to mainly use water as the blowing agent from the viewpoint of the impact on workers. However, since the methylene chloride acts as a blowing agent and at the same time has the effect of improving the compatibility between the polyol component and components such as the catalyst, it accounts for 10% or less of the total, preferably 0.
It is suitable to use within the range of 5 to 3%. When water is used as a blowing agent, it is blended in an amount of 0.1 to 5%. In order to increase the expansion ratio to 15 times, 1 to 4% of water may be added.

The above two-component foamed urethane resin consisting of liquid A and liquid B is produced at a temperature of 5 to 30°C at 0 to 30°C after mixing liquid A and liquid B.
It hardens in 30 seconds, and can be injected into holes drilled in other holes using the packer used in the conventional method proposed by the inventors. The use of the newly developed rock bolt by et al. is suitable because the urethane resin can be injected smoothly into a long hole without curing the urethane resin in the middle of the hollow pipe such as the rock bolt.

The rock bolts developed by the present inventors are of the driving type, in which urethane resin is injected after the rock bolt is driven into a hole drilled in the rock using a rock drill such as a jumbo drill, and the rock bolt itself is driven by a rock drill such as a jumbo drill. There is also a self-drilling type that can be used as a drill.

Figure 1 shows a driving type lock bolt.

This rock bolt consists of a packer part 1 made of a hollow pipe with a closed end, and a rock bolt main body 2 made of a hollow pipe.
are joined with threaded joint 3, and the outer diameter is 271 m and the inner diameter is 14 m.
1 piece has a total length A of about 3 m, a packer part 1 length B of 1 m,
The length C of the lock bolt body 2 is set to 2 m.

A diameter of 5 m is attached to the outer periphery of the tip of the packer part 1.
Ten chemical liquid discharge holes 4 of s are formed. On the other hand, a stepped portion 1a is provided at the rear end of the packer portion 1 adjacent to the threaded portion, and the stationary mixer 5 shown in FIGS. It is inserted and fixed with the distal end facing toward the distal end of the packer portion 1. The stationary mixer 5 includes a root side ring portion 6.
A linear central axis 5a extending forward (in the direction of arrow X) from the center of
Centering on , V-shaped double blades 5b are tiltedly arranged at regular intervals in the left half, and single blades 5C are tiltedly arranged at regular intervals in the right half. Liquid A and liquid B are received in the left and right halves, respectively, and both liquids are transferred while being rotated in the same direction (direction of arrows A and B). In this case, the right half is provided with a single blade 5C1 and the left half is provided with a V-shaped double blade 5b, and when the urethane resin rotates from the right half to the left half, the inlet side is wide and the outlet side is narrow. Letter-shaped double blade 5b
The flow speed increases due to the action of , and returns to the initial speed when returning from the left half to the right half. In other words, liquid A and liquid B are on the left half,
Mixing occurs while rotating in the same direction due to the difference in flow velocity between the right halves, and mixing occurs by rotating liquids A and B in opposite directions and colliding them at the intersection, as in the past. Since it is not a liquid, it is mixed and sent forward while maintaining the initial flow rate at the time of injection. In other words, the rock bolt is equipped with such a special static mixer 5, which allows the urethane resin, which hardens extremely quickly, to be mixed and transferred without curing in the middle, and to be smoothly discharged from the tip. . Also,
As shown in FIG. 1, a joint 7 with a check valve is screw-jointed to the rear end of the lock bolt main body 2 and has a one-touch connection mechanism (not shown) in its opening. As shown in FIG. 3, the rock bolts are inserted upward (angle θ=10~ 200), and the hose 11 with the connection unit 10 can be attached to the joint 7 with a check valve at the rear end with a single touch. In FIG. 3, reference numeral 12 denotes a urethane press-in pump that feeds liquids A and B of two-component foamed urethane resin into the hose 11.

Figure 4 shows two types of self-drilling type lock bolts. The lock bolt shown in Fig. 4(a) is constructed by joining a backer part 1 and a lock bolt main body 2 with a screw joint 3, but the tip of the backer part 1 is open, and the open part A drill portion (see FIG. 5) 13 is fitted into the drill portion. This drill part 13 has four blades 14 provided at 90° intervals in the circumferential direction on the end face of the tip, a center hole 15 is formed in the center of the end face, and each blade has a center hole 15 between the blades. An outer peripheral hole 16 is formed. Note that the joint with a check valve is installed when the urethane resin is press-fitted. Since the other parts are the same as the lock bolt shown in FIG. 1, the same parts are given the same reference numerals. The lock bolt shown in FIG. 4(b) has a drill part 17 at the tip of the packer part 1.
are integrally formed. In this case, the blade portion 18 of the drill is formed to be bifurcated from the base, and the tips of the bifurcated portions are each formed into a blade 19. An outer circumferential hole 20 is formed at the base of the branching blade. The other parts are the same as the lock bolt shown in Figure 1.

This invention uses the above-mentioned rock bolt, and as shown in FIG. A rock bolt is inserted into the ceiling part 8 in an upward direction so as to form an angle θ of 10 to 20@ with respect to the surface A, and rock consolidation is performed. In FIG. 6, 26 is a consolidated region formed by hardening of the penetrating resin. To explain in more detail, when using a driving type rock bolt, insert a rock drill such as a jumbo drill into the ceiling part 8 at the tip of the tunnel face at predetermined intervals along the ceiling as shown in Figure 7. Hole 22 is drilled by hole 21 (upwards from 10 to
20″ angle).

Then, a rock bolt shown in FIG. 1 is inserted into the drilled hole 22, and a driving adapter 23 is attached to the rear end of the rock bolt main body 2 as shown in FIG. Then, attach the check valve fitting 25 to the rear end of the driven lock bolt as shown in FIG. It can be installed by attaching it to 25 with one touch. Next, pour urethane resin liquids A and B from the hose 11 into the lock bolt.
Inject at a pressure of ~20 kg/cnl. The A and B liquids press-fitted in this way reach the splash joint 3 in a laminar flow state, and after reaching the packer part 1, the static mixer 5 (see Figure 1) The mixture is mixed and in that state is discharged from the chemical discharge hole 4 at the tip of the rock bolt. In this case, the urethane resin liquid discharged first is
The resin flows from the tip side of the hole 22 toward the opening, hardens in the process, and reaches a completely hardened state by the time it reaches the opening of the hole 22, closing the opening and preventing leakage of the resin to be discharged later. Therefore, there is no need to use a gasket to close the opening of the hole 22 as in the conventional method. When the penetrating resin hardens, the press-fitting pressure of the urethane press-fitting pump suddenly increases, so the press-fitting of the resin is stopped and the connection unit 10 is removed with one touch. In this way, the lock bolt is fixed in the hole 22 7
In addition, the other ridges around the hole 22 are solidified with a cured resin. This state is shown in FIG. In this way, rock bolts are inserted into the holes 22 drilled at predetermined intervals in the ceiling portion 8 at the tip of the tunnel face, and rock consolidation is performed. 26 is a consolidation area. As a result, as shown in FIG. 11, the entire top panel 8 is reinforced by the synergistic effect of the plurality of lock bolts and the consolidated regions 26 around them.

As shown in FIG. 6, the solidified region has a θ of 10 to 20.
It is formed around a rock bolt that is tilted upward at a small inclination angle of 200 cm and is nearly horizontal, and can effectively support the pressure of the ground. The cylindrical consolidation area 26 is formed by a resin that hardens very quickly, so it has a small diameter, and therefore, when drilling further forward beyond the consolidation area 26, there is no conventional wasted part. A (first
(See Figure 5). Therefore, it is possible to effectively perform excavation without causing a situation in which a portion hardened with resin is further excavated and removed during excavation.

In Fig. 6, the rock bolt is inserted diagonally upward from the corner formed by the ceiling surface of the top panel and wall surface B at the tip of the tunnel face, but the above angle is inserted from the part below the corner. It may be inserted diagonally upward in the same state, or it may be inserted diagonally upward from a portion of the top plate 8 slightly above the corner.

Also, when using the self-drilling type lock bolts shown in Figures 4(a) and (b), the angle θ between the central axis of the lock bolt and the extension surface A is 10 to 20, as shown in Figure 6. ″
It is necessary to do so so that

More specifically, as shown in FIG. 12, the rock bolt is attached to the rock drill 28 as a drill, and when drilling a hole,
Water and air are press-fitted into the rock bolt from the water and air supply pipe 29a provided in the rock drill 28 to form the center hole 15 at the tip of the rock bolt. The hole 22 is drilled while being discharged from the outer circumferential hole 16 and dirt, sand, etc. scraped by the blade of the rock bolt are moved backward inside the hole 22 along the outer periphery of the rock bolt and discharged to the outside from the opening of the hole 22. conduct. In this way, the hole 22 is formed using the rock bolt as a drill, the rock bolt is left in the hole 22, and the joint 25 with a check valve is connected to the rear end of the rock bolt, as shown in FIG. Connect the hose 11 with the connection unit 10 with one touch, inject the two-component foamed urethane resin liquids A and B, and
Center hole 15 provided in the blade at the tip of the lock bolt. It is discharged from the outer peripheral hole 16 and solidified into rock (see Fig. 6) in the same manner as the driving type.

In this way, the 11th
As shown in the figure, lock bolts are driven at predetermined intervals along the arch of the top plate 8, and a solidified area 26 of urethane resin is formed around the lock bolts, thereby reinforcing the top plate 8. Furthermore, although the rock bolts are distributed within a range of 90 degrees in Figure 12, they are not limited to this, and can be distributed at any angle within the range of 90 to 1200 degrees, and in some cases even more. Can be distributed angularly.

〔Effect of the invention〕

As described above, in the present invention, the central axis of the rock bolt is 10 to
The rock bolt is tilted upward at an angle of 20°, and a two-component foamed urethane resin is used as the rock solidification chemical that takes a short curing time after mixing the two components, and is press-fitted into the rock bolt. Around the rock bolt, a consolidation zone becomes formed at an effective angle to support the pressure of the earth. Moreover, unlike the conventional method, a part of the consolidated area does not enter the planned excavation area of the tunnel face and that part is excavated, so there is no waste of urethane resin, and at the same time, the consolidation area There will be no obstacles to excavation, and tunnel excavation can be carried out efficiently.In addition, when press-fitting the urethane resin, the two-component foamed urethane resin, which has a short curing time, is used as a chemical solution on the tip side of the rock bolt. The urethane resin is discharged from the discharge hole and hardens as it flows from the tip of the hole drilled in the rock in the direction of the opening, blocking the vicinity of the opening of the hole and preventing leakage of the urethane resin discharged thereafter. This eliminates the need for the complicated work of installing a gasket on the rock bolt to block the hole.Furthermore, the injected resin properly penetrates into the rock and hardens quickly, so it is not necessary to apply a large amount of urethane resin to the rock as in the past. This eliminates the waste of infiltrating more than the necessary amount, and it is possible to achieve a significant saving in the amount of resin used, and at the same time, a significant reduction in working time.However, according to this invention, the As is clear from the comparison between Fig. 11 and Fig. 17, the number of holes to be drilled is reduced compared to the conventional method when solidifying a certain area of the ceiling. Although the number of lock bolts inserted therein also increases, in this invention, the lock bolt 1
Since the curing time of the urethane resin per book is shorter than that of conventional methods, the overall construction time can be significantly shortened. Furthermore, since the amount of resin used per lock bolt is significantly smaller, even if the number of lock bolts increases, the amount of chemical liquid used is significantly smaller than in the conventional method. In addition, the 11th
As can be seen from the comparison between the figure and Fig. 17, the diameter of the cylindrical consolidation area formed around the rock bolt is smaller in this invention than in the conventional method, but the reinforcing effect is That's enough. In other words, in the conventional method, since the urethane resin cures slowly, the amount of resin liquid that permeates naturally increases, and the diameter of the solidified area that is formed around the rock bolt increases, which wastes the urethane resin. It is said that it was in Uruchino. Further, according to the method of this invention,
Since the urethane resin hardens extremely quickly, there is no leakage of the chemical solution to the front of the face through other piles, and therefore, there is no need for conventional concrete spraying treatment even on soft rock such as sand. , it is possible to perform rock consolidation, and it also has the effect of improving workability on soft rock.

Next, examples will be described together with comparative examples.

First, as the A liquid (polyol component) of the two-component foamed urethane resin, three types of A liquid 1. n, I[
I prepared I.

The above three types of A liquid 1. The characteristics of n, I[ are shown in Table 2.

In addition, as B liquid (isocyanate component), three types of B liquid 1. shown in Table 3 were used. ff, III was prepared.

Next, using the above-mentioned liquids A and B, rock consolidation was performed in the following manner.

[Example work]

70 along the arch of the ceiling at the top of the tunnel face.
Thirteen holes were drilled upward at cm intervals (with an inclination angle θ of 10 to 20 degrees with respect to the horizontal plane), and among these holes, holes were drilled from one end of the arch shape to the other end. Insert the drive-in type lock bolts shown in Figure 1 in order, and add the above A liquid ■ and B liquid I from the lock bolt at one end of the arch using a hose with a connecting unit.
: 1. Rock consolidation was performed by press-fitting at a pressure of 20 kg/cnt.

This solidified state was as shown in FIG.

[Comparative example]

According to the conventional method, a total of 7 holes were made in the top plate at the tip of the cutting blade at 140 cm intervals along the arch of the top plate, a backer with a packing attached to the base was sent into the holes, and after mixing the two liquids,
Rock consolidation was performed by injecting a two-part urethane foam resin that hardens in ~5 minutes. The solidified state was as shown in Fig. 17.

Table 4 shows a comparison of the hole drilling time, the two-component foam urethane resin injection time, and the total chemical solution (urethane resin) amount in Example 1 and Comparative Example.

(The following is a margin) Table 4 (The following is a margin) As is clear from Table 4, since the number of holes is large in Example 1, the drilling time is longer than that of the comparative example, but the time required to press in the resin liquid is Since the press-fitting time is extremely short, the press-fitting time can be significantly shortened. As a result, the total time required from drilling the hole to press-fitting is 11 minutes in Example 1, compared to 210 minutes in the comparative example.
It now takes 7 minutes, a 44% reduction. Moreover, the total amount of chemical solution was 700 kg in the comparative example, whereas it was 208 kg in Example 1, which was a decrease of 68%. From this, it can be seen that according to Example 1, it is possible to realize a significant reduction in construction time and a significant saving in the amount of chemical liquid used compared to the conventional method. Moreover, according to Example 1, when inserting a lock bolt into a hole and injecting a chemical solution, there is no need to attach a seal to the lock bolt each time as in the comparative example, so the complexity of installing the seal is eliminated. The effect of improving workability can also be obtained. Further, according to Example 1, the consolidated area 26 formed during rock consolidation is at an angle close to horizontal as shown in FIG. Therefore, the pressure of the ground can be effectively supported, and the lower part of the consolidation area does not get in the way of excavation. On the other hand, in the comparative example, the 15th
As shown in the figure, the consolidated area is wide and upward, and at the same time, the lower part A of the consolidated area is over the planned excavation path, so it is not effective in bearing the pressure of the ground. Moreover, the above-mentioned portion A becomes an obstacle during excavation.

[Example 2] Solution A and Solution B were used as chemical solutions. Rock consolidation was performed in the same manner as in Example 1 except for the above. As a result,
This was almost the same as in Example 1, and the same extremely excellent effects as in Example 1 were obtained.

[Example 3] As the chemical solutions, A solution (■) and B solution (■) were used. Rock consolidation was performed in the same manner as in Example 1 except for the above. In this case as well, extremely excellent effects substantially similar to those in Example 1 were obtained.

As described above, the method of the present invention makes it possible to significantly shorten the construction time and the amount of urethane resin liquid used without creating wasteful consolidation areas, and also to simplify the construction work. I understand Shiuro.

[Brief explanation of drawings]

Fig. 1 is a longitudinal cross-sectional view of a driving type rock bolt used in the present invention, Fig. 2 (a) is a perspective view of a stationary mixer installed in the lock bolt, Fig. 2 (b) is a side view thereof, and Fig. 2 (b) is a side view thereof. Figure 3 is an explanatory diagram of press-fitting resin into the lock bolt, Figure 4 (a) is a vertical cross-sectional view of a self-drilling type lock bolt, and Figure 4 (b) is a vertical cross-section of another self-drilling type lock bolt. 5 is an enlarged perspective view of the main part of FIG. 4(a), FIG. 6 is an explanatory diagram showing an example of construction of the present invention, and FIGS. 7, 8, 9, and 10 are Fig. 1 is an explanatory diagram of the use of rock bolts, Fig. 11 is a state diagram showing the construction state of an embodiment of the present invention, looking at the top plate at the tip of the tunnel face, Figs. 12, 13, and 11. Figure 14 is Figure 4(a),
(b) is an explanatory diagram of the use of the rock bolt, Fig. 15 is a vertical cross-sectional view showing the construction state of the conventional example, Fig. 16 is its cross-sectional view, and Fig. 17 shows the consolidation area in Fig. 16 individually. FIG. ■...Packer part 2...Rock bolt body 3.
...Threaded joint 4...Medical solution discharge hole 22...Hole 2
6... Consolidation area Fig. 2 (a) Fig. 3 Fig. 6 Fig. 11 zb Fig. 14 fxis Fig. 16 Fig. 17

Claims (2)

[Claims] (1) A hole is drilled in the top plate at the tip of the tunnel face so as to extend in the tunnel excavation direction, and a rock bolt having a chemical discharge hole on the tip side is inserted to the base and positioned in this hole, A chemical solution for rock consolidation is press-fitted into the rock bolt, and after the hole is filled with the chemical solution for rock consolidation, it is allowed to penetrate into the rock. A method of solidifying rock by hardening a penetrating rock solidifying chemical solution, the rock bolt is set so that the central axis of the rock bolt is A rock consolidation method characterized by tilting upward at an angle of 10 to 20 degrees with respect to an extended surface and using a fast-curing two-component foamed urethane resin as a rock consolidation chemical. (2) The rock consolidation method according to claim 1, wherein the fast-curing two-component foamed urethane resin has a curing time of 5 to 30 seconds after mixing the two components.