CN104446259A - Anchor rod anchoring agent applied to reinforcing underground broken rock body - Google Patents

Abstract

The invention relates to a bolt anchoring agent suitable for underground broken rock mass reinforcement, which is characterized in that it is composed of the following raw materials in the following weight percentages: composite portland cement 30.6%-34.0%, natural river sand 60.3%-63.9% , Polycarboxylate water reducer 0.6%-0.9%, expansion agent 1.5%-1.8%, steel slag powder 3.0%-3.5%. It fundamentally solves the problems of long construction period, high cost, large waste, and non-resolved problems in existing reinforced concrete reinforcement methods. The rock is reinforced, so that the broken rock becomes a strong foundation for the roadway reinforced by bolts, so that the reinforced broken rock mass is safe and reliable, and meets the production requirements.

Description

Bolt anchoring agent suitable for underground broken rock mass reinforcement

technical field

The invention relates to bolt reinforcement technology in geotechnical engineering, in particular to a bolt anchoring agent suitable for strengthening broken rock mass underground.

Background technique

During the excavation process of mine underground roadway, there are often broken rock sections, which need to be reinforced to meet the needs of production. At present, the commonly used method is to adopt reinforced concrete reinforcement method, and it only resists the pressure generated by the broken rock mass, and there is no such thing as In many cases, due to too much pressure, the cross-section of the reinforced concrete structure needs to be increased a lot, and the steel bars configured are quite amazing. This method has a long construction period, high cost, and large waste.

At present, as one of the main support forms of underground engineering and rock slopes, bolts play an important role in maintaining the stability of civil engineering, especially in jointed and fissured rock masses, the reinforcement effect of bolts on rock masses is very obvious . However, based on the construction environment of the broken rock mass underground, it is necessary to complete the rock mass reinforcement in a short period of time under unfavorable conditions such as humidity and blasting vibration. High requirements are difficult to meet with the existing bolt anchoring agent.

Contents of the invention

The purpose of the present invention is to provide a kind of bolt anchoring agent suitable for the reinforcement of broken rock mass underground, which fundamentally solves the problems of long construction period, high cost, large waste, and not a permanent cure in existing reinforced concrete reinforcement methods. The problem is that it applies a large anchoring force to the bolt reinforcement of the broken rock mass underground, and can reinforce the broken rock, so that the broken rock becomes a strong foundation for the roadway reinforced by the bolt, so that the broken rock mass after reinforcement is safe, reliable, and meets Production requirements.

Technical scheme of the present invention is:

A bolt anchoring agent suitable for underground broken rock mass reinforcement is characterized in that it consists of the following raw materials in the following weight percentages:

Steel slag powder 3.0% - 3.5%

Composite Portland cement 30.6%-34.0%

Natural river sand 60.3%-63.9%

Polycarboxylate water reducer 0.6% - 0.9%

Expanding agent 1.5% - 1.8%.

The above-mentioned bolt anchoring agent suitable for underground broken rock mass reinforcement should be mixed with water and stirred evenly when used. The weight ratio of the two is:

Anchoring agent 88.2%-89.9%

Water 10.1%-11.8%.

The above-mentioned bolt anchoring agent suitable for the reinforcement of broken rock mass underground, the fineness modulus of the natural river sand is within the range of the fineness modulus of medium sand, the mud content is less than 2.0%, and the mud content is less than 0.5%, The particle size of river sand is below 3mm.

The above-mentioned bolt anchoring agent suitable for the reinforcement of broken rock mass underground, the expansion agent adopts HEA expansion agent.

The above-mentioned bolt anchoring agent suitable for underground broken rock mass reinforcement, the particle size of the steel slag powder is 45 μm±10 μm, the specific surface area is ≥400m ² /kg, and the 28-day activity index is ≥80%.

The beneficial effects of the present invention are: the use of the above-mentioned ratio of the bolt anchoring agent can not only reinforce the broken rock mass, but also produce high-strength anchoring force, which is suitable for various harsh conditions in the underground, and is especially suitable for the reinforcement of large-scale rock mass fracture zones. The reinforcement depth of the broken zone is large and the width is wide; the anchoring effect can be completed in a short time, that is, its compression and tensile resistance can reach the best working state in a short time, and the construction speed is fast; the anchoring agent has high fluidity, permeability and expansion It can restore the broken rock mass to a complete state after reinforcement; the anchoring agent has high strength, and compared with ordinary cement mortar, the strength is at least doubled, so the length of the anchor rod can be shortened during the construction process, and the overall cost can be reduced. It is more than 30% lower than ordinary anchoring agents, which significantly improves economic benefits; at the same time, it is safe and reliable. Compared with existing anchoring agents, it can reinforce the same type of broken rock mass, and the reliability guarantee rate is as high as 98%. The reinforced rock mass Applicable security is guaranteed within the service period.

Wherein, the effect of each component of anchoring agent is as follows:

(1) The cementitious material adopts composite Portland cement, which has strong corrosion resistance, improves the durability of the anchoring agent material, and enhances the ability to resist the erosion of natural factors such as underground water;

(2) The fine aggregate is made of natural river sand, whose surface structure and specific surface area are better than artificial sand, which is beneficial to improve the fluidity and strength of the anchoring agent;

(3) The admixture adopts polycarboxylate water reducing agent to change the interface state of each component material of the anchoring agent, especially the interface state of the fine particle material, reduce the surface tension, and improve the fluidity and permeability of the anchoring agent; in addition, add an expansion agent at the same time , so that the anchoring agent has a certain expansibility after hardening, and fills the gaps in the rock mass;

(4) Steel slag powder, which is produced from steel slag discharged from converter steelmaking through water quenching, mainly composed of oxides of calcium, iron, silicon, magnesium and a small amount of aluminum, manganese, phosphorus, etc. The main mineral phase is a solid solution formed by tricalcium silicate, dicalcium silicate, calcium aluminoferrite, silicon and magnesium oxides, and also contains a small amount of free calcium oxide. Since the steel slag powder has certain activity, it can increase the late strength of the anchoring agent; it can further consume Ca(OH) ₂ produced by cement hydration, reduce the alkalinity, improve the corrosion resistance of the anchoring agent, and inhibit the alkali-aggregate reaction; it can improve The ease and pourability of the anchoring agent mixture; can reduce the cost of the anchoring agent; and provide another way for the utilization of industrial waste.

Through many experiments, the test index of anchoring agent of the present invention is as shown in table 1:

Table 1

Description of drawings

Fig. 1 is the vertical view of the bolt reinforcement principle of the broken rock mass in the underground;

Fig. 2 is a schematic cross-sectional view of the reinforcement of broken rock mass downhole by the present invention.

In the figure: L1-horizontal distance of reinforcement bolt, L2-distance on the slope of reinforcement bolt, L3-anchor length of bolt; A-main gap of anchoring agent penetration, B-branch gap of anchoring agent penetration, C-anchor head, D- Anchor rod, E-anchor body, F-broken rock mass, G-drilling diameter.

Detailed ways

The weight ratio of the bolt anchoring agent suitable for underground broken rock mass reinforcement is shown in Table 2.

Table 2

Composite Portland cement natural river sand Superplasticizer expansion agent Steel slag powder 30.6%-34.0% 60.3%-63.9% 0.6%-0.9% 1.5%-1.8% 3.0%-3.5%

When in use, it is mixed with water and stirred evenly, and the weight ratio of the two is shown in Table 3.

Wherein, the fineness modulus of the natural river sand is within the range of the fineness modulus of medium sand, the mud content is less than 2.0%, the mud content is less than 0.5%, and the river sand particle size is less than 3mm. The expansion agent is HEA expansion agent, which is a double effect of expansion in the plastic period and expansion in the hardening period, which fully compensates for the shrinkage of concrete. agent. The steel slag powder has a particle size of 45 μm±10 μm, a specific surface area of ≥400 m ² /kg, and an activity index of ≥80% in 28 days. Water adopts tap water.

Now provide three specific descriptions of embodiment:

Example 1

The components and water consumption of the anchoring agent are shown in Table 4 (in kg).

Table 4

The index test results are shown in Table 5.

table 5

Example 2

The components and water consumption of the anchoring agent are shown in Table 6 (in kg).

Table 6

The index test results are shown in Table 7.

Table 7

Example 3

The components and water consumption of the anchoring agent are shown in Table 8 (in kg).

Table 8

The index test results are shown in Table 9.

Table 9

As shown in Figure 1 and Figure 2, after the anchoring agent of the present invention is mixed with water to make a slurry, it is injected into the anchor hole by pressure grouting, then the grouting pipe is connected, and the grouting pump is started until the grout is released from the grouting stop. Extrude around the plug, turn off the grouting pump, wait for the pressure to weaken to a safe value, remove the grouting pipe and block the grouting hole with anchoring agent or wooden plug. The grouting pressure is generally 2-3 times of the hydrostatic pressure of the groundwater. At the same time, the crack resistance of the rock formation should be considered, and it should be determined after testing according to the site conditions. But the instantaneous maximum pressure value should not exceed 0.5MPa. The anchoring agent enters the broken rock mass F through the anchoring agent penetration main gap A and the anchoring agent penetration branch gap B. Due to the high permeability, high fluidity, high strength and durability of the product, the rock mass in the infiltrated area forms a complete rock mass. The controllable range of reinforcement and the reinforcement depth are controlled by controlling the horizontal distance L1 of the reinforcement anchor rod, the distance on the slope of the reinforcement anchor rod L2, the anchorage length L3 of the anchor rod, and the diameter of the drilling hole D. Finally, through the anchor head C, anchor rod D and anchor body E Temporary and permanent fixation of the broken rock mass F.

Claims (5)

1. A bolt anchoring agent suitable for downhole broken rock mass reinforcement is characterized in that it is composed of the following raw materials in the following weight percentages: Steel slag powder 3.0% - 3.5% Composite Portland cement 30.6%-34.0% Natural river sand 60.3%-63.9% Polycarboxylate water reducer 0.6% - 0.9% Expanding agent 1.5% - 1.8%. 2. The bolt anchoring agent suitable for underground broken rock mass reinforcement according to claim 1, characterized in that, when in use, it is mixed and stirred evenly with water, and the weight ratio of the two is: Anchoring agent 88.2%-89.9% Water 10.1%-11.8%. 3. The bolt anchoring agent suitable for downhole broken rock mass reinforcement according to claim 1, characterized in that: the fineness modulus of the natural river sand is within the fineness modulus range of the medium sand, and the mud content Less than 2.0%, the mud content is less than 0.5%, and the river sand particle size is less than 3mm. 4. The bolt anchoring agent suitable for underground broken rock mass reinforcement according to claim 1, characterized in that: the expansion agent is HEA expansion agent. 5. The bolt anchoring agent suitable for underground broken rock mass reinforcement according to claim 1, characterized in that: the particle size of the steel slag powder is 45 μm ± 10 μm, the specific surface area is ≥ 400 m ² / kg, and the 28-day activity index is ≥ 80%.