CN116122307B - Slope emergency multistage reinforcement method - Google Patents

Abstract

The invention discloses a method for emergency multi-stage reinforcement of a slope, comprising the steps of: drilling a hole in the slope and washing it with water; placing a U-shaped circulation pipe and a phase change liquid pipe into the borehole, injecting a circulating refrigerant liquid into the U-shaped circulation pipe to freeze the pore water of the rock and soil body, and realizing the first reinforcement of the slope; injecting a high-pressure phase change liquid into the borehole through the phase change liquid pipe to change the double electric layer structure of the slope, changing it from hydrophilic to hydrophobic, and realizing the second reinforcement of the slope; continuing to inject the circulating refrigerant liquid into the U-shaped circulation pipe to freeze the phase change liquid and pore water to improve their strength, and realizing the third reinforcement of the slope; withdrawing the U-shaped circulation pipe and the phase change liquid pipe, installing an anchor body in the borehole and injecting a new grouting material, and realizing the fourth reinforcement of the slope; arranging a drainage hole that passes through the phase change liquid reinforcement area in the slope, and the liquid phase change liquid changes the double electric layer structure of the slope, improves the hydrophobicity of the slope, and realizes the long-term reinforcement of the slope. The invention can effectively prevent the occurrence of geological disasters on the slope.

Description

Emergency multi-level slope reinforcement method

Technical Field

The invention relates to the field of geological disaster prevention and control, and in particular to a slope emergency multi-stage reinforcement method.

Background technique

In order to cope with sudden geological disasters, reduce the losses caused by geological disasters, and effectively prevent and control landslide disasters, it is particularly important to adopt reasonable reinforcement measures to effectively control and reinforce landslides.

At present, chemical electroosmosis, cement-based grouting and cement mortar anchoring are the commonly used methods for slope reinforcement. However, the above three reinforcement methods still have some obvious shortcomings, which are as follows: (1) Chemical electroosmosis: ① high power consumption and uneven reinforcement effect; ② electrode corrosion and groundwater pollution; (2) Cement-based grouting: ① long coagulation and hardening cycle, insufficient early strength, unable to achieve timely and effective reinforcement; ② easy to shrink and crack in the later drying, resulting in irreversible cracks; (3) Cement mortar anchoring: ① difficult to meet the emergency support needs of harsh working conditions, affecting the anchoring performance and stability of the anchor; ② cement-based grouting materials shrink in the later drying, which may cause cracks at the grouting body-rod body interface and reduce the anchoring force of the anchor.

There is an urgent need to explore a slope reinforcement method with the advantages of excellent performance, good durability, rapid consolidation and protection of the ecological environment, in order to achieve the purpose of rapid coagulation and hardening, micro-expansion, rapid and long-term reinforcement of the slope.

Summary of the invention

The main purpose of the present invention is to provide a method for emergency multi-stage reinforcement of slopes with excellent performance, good durability, rapid consolidation and protection of the ecological environment.

The technical solution adopted by the present invention is:

A slope emergency multi-stage reinforcement method is provided, comprising the following steps:

S1. Drill holes on the slope, and the drilling arrangement adopts a five-color hole arrangement to achieve a superposition effect, so that the slope reinforcement effect forms a network structure;

S2. Clean the borehole with clean water and insert a U-shaped circulation tube and a phase change liquid tube into the borehole;

S3, injecting circulating refrigerant liquid into the U-shaped circulating pipe to freeze the pore water of the rock and soil to improve its strength and realize the first reinforcement of the slope;

S4, injecting high-pressure phase-change liquid into the borehole through the phase-change liquid pipe to change the double-layer structure of the slope from hydrophilic to hydrophobic, thus achieving the second reinforcement of the slope;

S5. Continue to inject circulating refrigerant liquid into the U-shaped circulation pipe to freeze the phase change liquid and pore water to increase their strength, thereby achieving the third reinforcement of the slope;

S6. Remove the U-shaped circulation pipe and the phase change liquid pipe, install the anchor body in the borehole and inject the new grouting material. The new grouting material is filled in the pores of the slope and the anchor, thus realizing the fourth reinforcement of the slope.

S7. Drainage holes are arranged on the slope. As the cooling energy of the phase change liquid disappears, the phase change liquid changes from solid to liquid. It comes into contact with the clay particles in the slope, changes the double electric layer structure on the surface of the clay particles, and changes the hydrophilicity of the slope to hydrophobicity, completing the fifth long-term reinforcement of the slope.

Following the above technical solution, the method also includes step S0: drilling and sampling, surveying, geophysical exploration and monitoring the slope, determining the depth of the potential sliding surface at each position of the slope through mechanical calculation, obtaining the position and shape of the potential sliding surface, testing the borehole sampling to determine the physical and mechanical parameter values of the slope, and calculating the magnitude of the sliding force, determining the number and range of reinforced boreholes, and arranging the boreholes.

Following the above technical solution, drill holes are set along the direction of slope deformation and failure. The diameter of the drill holes is 15 to 30 cm, the spacing between drill holes is 2.5 to 5 m, the depth of the drill holes is 1.2 to 1.3 times the thickness of the potential sliding surface, and the deviation of the hole inclination is less than plus or minus 3 degrees.

Following the above technical solution, the new grouting material is a geopolymer grouting material, specifically a geopolymer prepared by orthogonal test using a composite grouting material based on fly ash, slag powder, metakaolin, sodium silicate solution, calcium oxide expansion agent, sodium hydroxide and deionized water.

Following the above technical solution, a plurality of induction rings are arranged on the wall of the drilled hole, and a temperature sensor and an acoustic emission detector are arranged in the inner cavity of the induction ring.

According to the above technical solution, the circulating refrigerant liquid in step S3 is antifreeze liquid with a temperature of -20°C to -42°C.

Following the above technical solution, the phase change liquid in step S4 is an ionic curing agent

Following the above technical solution, centering brackets are set on the anchor rod every 1.0 to 2.0 m along the axial direction; the steel bars of the anchor rod are straight, smooth, degreased and derusted; and the grouting pipe is placed into the drilled hole together with the anchor rod.

Following the above technical solution, the anchor rod and the new grouting material are combined into a reinforced anchor rod system.

According to the above technical solution, the phase change liquid pipe is arranged between the U-shaped circulation pipes.

Following the above technical solution, orthogonal test and range analysis method are used to optimize the drainage hole layout parameters, and the parameters include drainage hole length, hole diameter and inclination.

The beneficial effect of the present invention is that the drilling layout of the present invention adopts a multi-colored hole. Due to the mutual superposition effect between the multi-colored holes, the reinforcement range is rapidly increased, and a "tree root pile-network effect" effect is formed to firmly form the sliding surface and the slope into a whole.

Furthermore, artificial freezing is used to improve the anti-sliding parameters of the slope, greatly reducing the possibility of landslides, and greatly increasing the triggering threshold of rainfall factors, thereby improving the original anti-sliding stability of the slope; the permeability coefficient of the slope is reduced twice by phase change fluid, reducing rainfall infiltration and enhancing the stability of the slope; the new grouting material is quickly filled into the pores of the slope, the overall physical and mechanical strength is greatly improved, and the triggering threshold of rainfall factors is greatly increased, thereby improving the original anti-sliding stability of the slope; adding drainage holes that pass through the phase change fluid reinforcement area in the slope can quickly drain the water in the slope, thereby improving the anti-sliding stability of the slope after reinforcement. The water-reducing effect of the phase change fluid and the drainage function of the drainage holes achieve long-term reinforcement of the slope.

Furthermore, the present invention adopts ionic curing agent as phase change liquid, and utilizes ionic curing agent, phase change principle, new grouting material, and new grouting material anchor reinforcement system to perform emergency multi-stage reinforcement of slopes, which can prevent the occurrence of landslide geological disasters and quickly respond to the needs of sudden landslide disasters.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

FIG1 is a flow chart of a slope emergency multi-stage reinforcement method according to an embodiment of the present invention;

FIG2 is a block diagram of a refrigerant circulation system;

FIG3 is a schematic diagram of the structure of a five-hole arrangement of drilling holes for freezing a landslide;

Figure 4(a) is a schematic diagram of the slope interface reinforced by the refrigerant circulation phase change fluid;

Fig. 4(b) is a right side view of Fig. 4(a);

FIG5 is a schematic diagram of a slope freezing structure with multiple five-point holes and acoustic emission arrangement;

FIG6 is a schematic plan view of a geopolymer composite grouting anchor for slope reinforcement;

FIG. 7 is a schematic diagram of a range analysis method according to an embodiment of the present invention.

Detailed ways

In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

The present invention utilizes ionic curing agent, phase change principle, new grouting material, and new grouting material anchor reinforcement system to carry out an emergency multi-stage slope reinforcement method to prevent landslide geological disasters and quickly respond to sudden landslide disasters. Specifically, through the arrangement of drilling holes, it is expected to achieve the "tree root pile-network" reinforcement effect + phase change liquid-ionic curing agent + circulating refrigerant liquid-antifreeze liquid + new grouting material-new green geopolymer grouting material + new grouting material anchor reinforcement system + drainage hole, forming a multi-field coupling of chemistry, temperature, mechanics, etc. A kind of slope emergency multi-stage reinforcement method.

Embodiment 1: As shown in FIG1 , a slope emergency multi-stage reinforcement method of this embodiment includes the following steps:

S1. Drill holes on the slope, and the drilling arrangement adopts a five-hole arrangement;

S2. Clean the borehole with clean water and insert a U-shaped circulation tube and a phase change liquid tube into the borehole;

S3, injecting circulating refrigerant liquid into the U-shaped circulating pipe to freeze the pore water of the rock and soil to improve its strength and realize the first reinforcement of the slope;

S4, injecting high-pressure phase-change liquid into the borehole through the phase-change liquid pipe to change the double-layer structure of the slope from hydrophilic to hydrophobic, thus achieving the second reinforcement of the slope;

S5. Continue to inject circulating refrigerant liquid into the U-shaped circulation pipe to freeze the phase change liquid and pore water to increase their strength, thereby achieving the third reinforcement of the slope;

S6. Remove the U-shaped circulation pipe and the phase change liquid pipe, install the anchor body in the borehole and inject the new grouting material. The new grouting material is filled in the pores of the slope and the anchor, thus realizing the fourth reinforcement of the slope.

S7. Drainage holes are arranged in the slope to pass through the phase change liquid reinforcement area. As the cooling energy of the phase change liquid disappears, the phase change liquid changes from solid to liquid, and contacts the clay particles in the slope, changing the double electric layer structure on the surface of the clay particles, improving the hydrophobicity of the slope, and completing the fifth reinforcement of the slope.

Furthermore, the drainage holes can be optimized by orthogonal test and range analysis method (specifically shown in Figure 7, the parameters include drainage holes, length, hole diameter and inclination, as shown in Table 1 below).

Table 1: Drain hole layout parameters

In the preferred embodiment of the present invention, the length of the drainage hole is 12m, the diameter of the drainage hole is 130mm, and the inclination angle of the drainage hole is 7°.

Embodiment 2: A slope emergency multi-stage reinforcement method mainly comprises the following steps:

(1) Drilling, sampling, surveying, geophysical exploration and monitoring are carried out on the slope. The depth of the potential sliding surface at each position of the slope is determined by mechanical calculation, and the position and shape of the potential sliding surface are obtained. The drill hole sampling is tested to determine the physical and mechanical parameter values of the slope;

(2) Calculate the magnitude of the sliding force based on the distribution of the potential sliding surface and the values of the physical and mechanical parameters, and determine the number and distribution of reinforcement holes;

(3) Determine the scope of soil reinforcement, arrange soil drilling, set along the direction of slope deformation and failure, the drilling diameter is 15-30cm, the drilling spacing is 2.5-5m, the drilling depth is 1.2-1.3 times the thickness of the sliding surface, the hole inclination deviation is less than plus or minus 3 degrees, and the drilling arrangement adopts a five-color hole (as shown in Figure 3) in order to achieve the "tree root pile" effect. When the drilling reaches the designed depth, stop drilling and clean it with clean water. As shown in Figure 4 (a) and Figure 4 (b), then insert the U-shaped circulation pipe and the phase change liquid pipe into the borehole. The U-shaped circulation pipe is a stainless steel copper pipe with good thermal conductivity. The hole plug is plugged at the starting end of the borehole. The hole plug is an iron plate plug. The input and output ports of the U-shaped circulation pipe and the phase change liquid inlet are reserved, and the free ends of the U-shaped pipe and the phase change liquid injection pipe are connected to the refrigeration system and the new grouting material injection system. An induction ring may be provided on the borehole wall, and a temperature sensor and an acoustic emission detector may be provided in the inner cavity of the induction ring to realize real-time collection of sliding surface temperature and deformation. The output ends of the temperature sensor and the acoustic emission detector may be connected to an external control system.

(4) The cold energy is delivered to the refrigerant storage tank through the refrigeration system (as shown in Figure 2), so that the temperature of the circulating refrigerant liquid drops to between -20 and -42℃. The refrigerant liquid can be selected from antifreeze, and its freezing point model is 42 type, and the freezing point is -42 degrees. The circulating refrigerant liquid transmits cold energy to the pore water of the slope to freeze the pore water of the rock and soil to improve its strength. The RA (amplitude to rise time ratio) and AF (average frequency) parameter thresholds of the acoustic emission detector signal are maintained between A-B and C-D to maintain the current temperature of the circulating refrigerant liquid. When the signal parameter threshold of the acoustic emission detector is not within this safety threshold range, the pressure of the cryogenic pump is increased to reduce the temperature of the circulating refrigerant liquid until the signal parameter threshold of the acoustic emission detector is within the safety range. After the slope is frozen, the overall physical and mechanical strength is greatly improved. The strength of the frozen soil is mainly determined by the strength of the ice, the strength of the soil skeleton, and the interaction between ice-unfrozen water-soil particles, completing the first reinforcement of the slope.

(5) The phase change liquid is injected into the borehole by high pressure injection to complete the second reinforcement of the slope. The grouting pressure is 1.5MP. The phase change liquid can be selected as an ion curing agent, which is economical, fast, durable and protects the ecology. The ion soil curing agent directly uses the soil on site as raw material for in-situ reinforcement. The functions of the phase change liquid mainly include providing freezing, short-term change of slope soil properties and long-term change of soil properties. Specifically: 1) To achieve freezing and increase the overall strength of the slope, the phase change liquid is selected as an ion curing agent instead of water or NaCl solution; 2) The second reinforcement phase change liquid only temporarily changes the double electric layer structure of the slope, changing it from hydrophilic to hydrophobic. The focus is on highlighting the role of the selected phase change liquid, because the phase change liquid must be injected into the borehole before the third reinforcement. The reason for choosing an ion curing agent instead of water or NaCl solution is to lay the groundwork for long-term reinforcement. 3) The reason for long-term reinforcement is that due to the disappearance of cold energy, the phase change liquid changes from solid to liquid, and the ions in the phase change liquid always exist in the pores of the slope. After the fourth reinforcement (new grouting anchor system), although the slope has reached stability, there will still be water environments such as rainfall or reservoir water level fluctuations. Due to the selection of the phase change liquid, the seepage of water in the pores of the slope in the later period will be prevented, thus strengthening its overall strength, so the purpose of long-term reinforcement is also achieved. This is also the reason why the phase change liquid was selected in the second reinforcement.

The refrigeration system transmits cold energy to the refrigerant storage tank, so that the temperature of the circulating refrigerant liquid drops to about -20 to -42°C. The circulating refrigerant liquid conducts cold energy to the phase change liquid and the unfrozen water in the slope pores to freeze the pore water and phase change liquid of the rock mass to increase its strength. The RA (amplitude to rise time ratio) and AF (average frequency) parameter thresholds of the acoustic emission detector signal are maintained between A-B and C-D to maintain the current temperature of the circulating refrigerant liquid. When the signal parameter threshold of the acoustic emission detector is not within this safety threshold range, the pressure of the cryogenic pump is increased to reduce the temperature of the circulating refrigerant liquid until the signal parameter threshold of the acoustic emission detector is within the safety range. In this process, the slope is reinforced again, that is, the third reinforcement, as shown in Figure 5.

The ratio of the phase change liquid to water in the embodiment of the present invention is selected to be 1:150, which can solve the problem of the difficulty of traditional cement grouting. Utilizing the refrigerant liquid circulation system, the cooled circulating refrigerant liquid is injected into the U-shaped circulation pipe at a displacement of ^0.5-2.5m3 /min, and the pressure of the cryogenic pump is gradually increased until the temperature of the soil around the borehole reaches the expected temperature. This method has little disturbance to the in-situ soil and is easy to operate. After freezing and the soil near the sliding surface is frozen, the strength parameters are significantly improved, which can directly improve the original anti-sliding stability of the slope and directly improve the self-strength of the sliding surface. An induction ring is provided on the borehole wall, and a temperature sensor and an acoustic emission detector are provided in the inner cavity of the induction ring to realize real-time collection of the temperature and deformation of the sliding surface. The output ends of the temperature sensor and the acoustic emission monitoring instrument should be connected to the external control system.

(6) Quickly withdraw the inserted U-shaped circulation tube and phase change liquid tube, and withdraw the induction ring as well, and assemble and place the anchor rod system. The anchor rod can be made according to the design requirements. In order to make the anchor rod in the center of the borehole, a centering bracket should be set on the anchor rod every 1.0 to 2.0 m along the axial direction; the steel bars of the anchor rod should be straight, smooth, degreased and derusted; when placing the anchor rod body, the rod body should be prevented from twisting and bending. The grouting pipe should be placed in the hole together with the anchor rod, with the pipe end 50 to 100 mm from the bottom of the hole. The angle of the rod body should be consistent with the inclination of the borehole. After installation, the rod body should always be in the center of the borehole. If the hole wall collapses, the hole should be re-drilled and cleaned until the anchor rod can be smoothly inserted.

(7) Grouting is performed in the grouting pipe. The new grouting material and anchor rod form a new grouting material anchor rod reinforcement system to complete the fourth reinforcement of the slope. The grouting material can be selected as a geopolymer grouting material. The geopolymer material is a composite grouting material based on fly ash, slag powder, kaolin, sodium silicate solution, calcium oxide expansion agent, sodium hydroxide and deionized water, and is prepared by orthogonal test. The geopolymer grouting material has the advantages of rapid consolidation, high initial strength, and good anti-seepage effect. The geopolymer grouting material can be filled in the pores of the slope body to play a reinforcement and anti-seepage function. When a certain grouting pressure is reached, the pressure is maintained, and the grouting pipe is pulled out after the pressure is released, and the grouting is supplemented to make the geopolymer grouting material in the borehole full, as shown in Figure 6. An acoustic emission detector can be installed at the potential sliding surface to realize the monitoring and early warning of landslides.

(8) The phase change liquid changes from solid to liquid. After it comes into contact with the clay particles in the slope, it replaces the exchangeable cations adsorbed on the surface of the clay particles through the electrochemical principle, changes the double electric layer structure on the surface of the clay particles, and can permanently change the hydrophilicity of the slope to hydrophobicity, thereby improving the shear strength of the slope. As long as there is water, the function of the phase change liquid will not be consumed by itself, but will continue to work, thereby completing the fifth reinforcement of the slope, that is, long-term reinforcement of the slope.

Embodiment 3: In another preferred embodiment of the present invention, a slope emergency multi-stage reinforcement method comprises the following steps:

(1) Drilling, sampling, surveying, geophysical exploration and monitoring of the slope are carried out to determine the depth of the potential sliding surface at each position of the slope through mechanical calculation, obtain the position and shape of the potential sliding surface, and test the drilled samples to determine the physical and mechanical parameter values of the slope;

(2) Calculate the magnitude of the sliding force based on the distribution of the potential sliding surface and the values of the physical and mechanical parameters, and determine the number and distribution of reinforcement holes;

(3) Determine the scope of rock and soil reinforcement, arrange soil drilling holes, and set them along the direction of slope deformation and failure. The drilling diameter is 15 to 30 cm, the drilling spacing is 2.5 to 5 m, the drilling depth is 1.2 to 1.3 times the thickness of the sliding surface, and the hole inclination deviation is less than plus or minus 3 degrees. The drilling arrangement adopts a five-color hole (as shown in Figure 3) in order to achieve the "tree root pile" effect.

(4) Before drilling, install the drill brace and positioning part in front of the drill rod, and then connect the drill bit; make sure that all parts of the machine are operating normally before drilling; during the drilling process, the position and posture of the drill bit are determined by the guide data received by the receiver at the tail of the drill bit. The operator compares it with the design coordinates entered in the computer before drilling, and makes timely adjustments when deviations occur; when the hole reaches the designed depth, stop drilling and clean it with clean water. Then insert the U-shaped circulation tube and the phase change liquid tube into the borehole, and plug it with a hole plug. The U-shaped circulation tube is a stainless steel copper tube with good thermal conductivity, and the hole plug is an iron plug, which will be removed when the anchor rod is placed.

(4) The refrigeration system delivers cold energy to the refrigerant storage tank, so that the temperature of the refrigerant liquid drops to about -20°C to -42°C. The refrigerant liquid conducts the cold energy to the pore water of the slope to freeze the potential landslide body. After the landslide body is frozen, the overall physical and mechanical strength is greatly improved. The strength of the frozen soil is mainly determined by the strength of the ice, the strength of the soil skeleton, and the interaction between ice-unfrozen water-soil particles - the first reinforcement of the landslide. After the first reinforcement of the landslide is completed, the refrigerant circulation is stopped.

(5) The phase change liquid is injected into the borehole by high pressure injection to complete the second reinforcement of the slope. The grouting pressure is 1.5MP. The phase change liquid is an ionic curing agent, which is economical, fast, durable and protects the ecology. The ionic soil reinforcement agent directly uses the soil on site as a raw material for in-situ reinforcement. The cold energy is transported to the refrigerant storage tank through the refrigeration system to reduce the temperature of the circulating refrigerant liquid to about -20 to -42°C. The circulating refrigerant liquid conducts the cold energy to the phase change liquid and the unfrozen water in the pores of the slope to freeze the pore water and phase change liquid of the rock and soil to increase its strength. In this process, the slope is reinforced again, that is, the third reinforcement, as shown in Figure 5. The ratio of the phase change liquid to water in the embodiment of the present invention is 1:150, which can solve the problem of the difficulty of traditional cement grouting. Utilize the refrigerant liquid circulation system, inject the cooled circulating refrigerant liquid into the U-shaped circulation pipe at a displacement of ^0.5-2.5m3 /min, and gradually increase the pressure of the cryogenic pump until the soil temperature around the borehole reaches the expected temperature. This method has little disturbance to the in-situ soil and is easy to operate. After freezing and the soil near the sliding surface, the strength parameters are significantly improved, which can directly improve the original anti-sliding stability of the slope and the inherent strength of the sliding surface. The ionic curing agent ratio can be multiple, as shown in Table 2 below. In this embodiment, the optimal ratio of the ionic curing agent is selected as 1:150; the optimal ratio is determined by the reduction of the plasticity index of the landslide soil after the ionic curing agent is added, as shown in Table 3 below. The Atterberg test can be carried out to calculate the liquid limit, plastic limit and plasticity index.

Table 2: Plasticity index of soil under different mix ratios

Table 3: Comparison of permeability coefficient before and after the action of ionic curing agent

(6) Quickly withdraw and insert the U-shaped circulation pipe and the phase change liquid pipe, and assemble and place the anchor system. Make anchors according to design requirements. In order to make the anchor in the center of the borehole, a centering bracket should be set on the anchor rod every 1.0 to 2.0 m along the axial direction; the anchor steel bar should be straight, smooth, degreased and derusted; when placing the anchor rod body, the rod body should be prevented from twisting and bending. The grouting pipe should be placed in the hole together with the anchor rod, with the pipe end 50 to 100 mm from the bottom of the hole. The angle of the rod body should be consistent with the inclination of the borehole. After installation, the rod body should always be in the center of the borehole. If the hole wall collapses, the hole should be re-drilled and cleaned until the anchor rod can be smoothly inserted.

(7) The grouting material is selected as a geopolymer grouting material. The geopolymer material is a composite grouting material prepared with fly ash, slag powder, kaolin, sodium silicate solution, calcium oxide expansion agent, sodium hydroxide and deionized water as the matrix. The composite grouting material has the advantages of rapid solidification, high initial strength, good anti-seepage effect, etc. The physical and mechanical properties of the geopolymer and the mechanical properties of cement mortar are specifically shown in Tables 4 and 5 below. The present invention obtains the best ratio of kaolin 35%-40%, fly ash 35%-40%, and slag 20%-25% through orthogonal test. The water glass modulus is 1.2-1.5, the water-binder ratio is 0.38-0.42, and the alkali activator preparation ratio is: the water glass solid content is 24%-28%.

Table 4: Physical and mechanical properties of geopolymers

Table 5: Mechanical properties of cement mortar

In summary, the advantages of the present invention include:

(1) The drilling layout adopts a five-color hole pattern to achieve the "tree root pile" effect. Due to the mutual superposition effect between the drill holes, a three-dimensional network skeleton is formed in the soil, and the reinforcement range is rapidly increased, forming a "tree root pile effect-network shape" that firmly integrates the potential sliding surface and the slope into a whole.

(2) During the first emergency reinforcement of the slope, holes are drilled and cleaned with clean water. The refrigerant liquid conducts cold energy to the clean water and pore water to freeze the pore water in the rock and soil to increase its strength. After the slope is frozen, the overall physical and mechanical parameters are greatly improved. By turning the water factor that endangers the stability of the landslide into an advantage and taking artificial freezing measures to improve the anti-sliding parameters of the sliding surface and slope, the possibility of landslides can be greatly reduced, and the triggering threshold of the rainfall factor can be greatly increased, thereby improving the original anti-sliding stability of the slope.

(3) During the second emergency reinforcement of the slope, the phase change liquid is injected into the borehole by high pressure injection. The phase change liquid fully exchanges charges with the slope particles, so that the treated slope changes from hydrophilic to hydrophobic. The "cementation" effect between the slope particles begins to occur. The slope is transformed into a new structure through ion exchange of the phase change liquid, thereby achieving a high degree of solidification and reducing the water absorption caused by the capillaries and soil pores in the slope, greatly improving the stability and bearing capacity of the slope. The phase change liquid can make the bound water film thinner and completely remove it, providing a convenient "channel" for the new composite grouting material to enter the pores and cracks of the rock and soil to reinforce the slope, making the reinforced slope stronger.

(4) During the third emergency reinforcement of the landslide, the refrigerant liquid transfers the cold energy to the phase change liquid and the unfrozen water in the pores. After the phase change liquid and the pore water in the slope are frozen, the overall physical and mechanical strength of the slope is greatly improved, and the triggering threshold of the rainfall factor is greatly increased, thereby improving the original anti-sliding stability of the slope.

(5) During the fourth emergency reinforcement of the slope, a new type of grouting material anchor reinforcement system was formed. The new composite material grouting anchor quickly solidifies and has good bonding performance. The grouting is dense and crack-free, and it can effectively bond the steel bars and rock and soil. The grouting material is selected as a geopolymer grouting material. The geopolymer material is a composite grouting material based on fly ash, slag powder, kaolin, sodium silicate solution, calcium oxide expansion agent, sodium hydroxide and deionized water. The geopolymer grouting material has the advantages of rapid consolidation, high initial strength, and good anti-seepage effect. The geopolymer grouting material has the advantages of rapid consolidation, high initial strength, and good anti-seepage effect. The geopolymer grouting material quickly fills the pores of the slope, greatly improves the overall physical and mechanical strength, and greatly increases the triggering threshold of the rainfall factor, thereby improving the original anti-sliding stability of the slope. This fourth emergency reinforcement of the landslide, due to the function of the phase change fluid itself and the new composite grouting material, is easier to enter the pores of the rock and soil, and the overall physical and mechanical strength is improved again.

(6) During the fifth long-term reinforcement of the slope, drainage holes are arranged in the slope that pass through the phase change liquid reinforcement area. As the cooling energy of the phase change liquid disappears, the phase change liquid changes from solid to liquid. After the liquid phase change liquid comes into contact with the clay particles in the slope, it replaces the exchangeable cations adsorbed on the surface of the clay particles through the electrochemical principle, changes the double electric layer structure on the surface of the clay particles, and can permanently change the hydrophilicity of the slope to hydrophobicity, thereby improving the shear strength of the slope. As long as there is water, the phase change liquid function will not be consumed by itself, but will continue to work. Adding drainage holes can quickly drain the water in the slope and improve the anti-sliding stability of the slope after reinforcement. The water-reducing effect of the phase change liquid and the drainage function of the drainage holes achieve long-term reinforcement of the slope.

(8) The reinforcement system reduces the permeability coefficient of the slope twice, reduces rainfall infiltration, and adds drainage holes after reinforcement, thereby enhancing the stability of the slope.

The reinforcement times of the present invention are as high as 5 times, achieving the purpose of emergency reinforcement and long-term reinforcement. The completed reinforcement system has the advantages of excellent performance, good durability, rapid consolidation, low cost and protection of the ecological environment, and has good promotion value.

It should be understood that those skilled in the art can make improvements or changes based on the above description, and all these improvements and changes should fall within the scope of protection of the appended claims of the present invention.

Claims (9)

1. A slope emergency multi-stage reinforcement method, characterized in that it comprises the following steps: S1. Drill holes on the slope, and the drilling arrangement adopts a five-hole arrangement; multiple induction rings are arranged on the hole wall of the drill hole, and a temperature sensor and an acoustic emission detector are arranged in the inner cavity of the induction ring; S2. Clean the borehole with clean water and insert a U-shaped circulation tube and a phase change liquid tube into the borehole; S3, injecting circulating refrigerant liquid into the U-shaped circulating pipe to freeze the pore water of the rock and soil to improve its strength and realize the first reinforcement of the slope; S4, injecting high-pressure phase-change liquid into the borehole through the phase-change liquid pipe to change the double-layer structure of the slope from hydrophilic to hydrophobic, thus achieving the second reinforcement of the slope; S5. Continue to inject circulating refrigerant liquid into the U-shaped circulation pipe to freeze the phase change liquid and pore water to increase their strength, thereby achieving the third reinforcement of the slope; S6. Remove the U-shaped circulation pipe and the phase change liquid pipe, install the anchor body in the borehole and inject grouting material, the grouting material fills the pores of the slope and the anchor, and the fourth reinforcement of the slope is achieved; S7. Drainage holes are arranged in the slope that pass through the phase change liquid reinforcement area. As the cooling energy of the phase change liquid disappears, the phase change liquid changes from solid to liquid. It comes into contact with the clay particles in the slope, changes the double electric layer structure on the surface of the clay particles, improves the hydrophobicity of the slope, and completes the fifth reinforcement of the slope. 2. The method for emergency multi-stage reinforcement of slopes according to claim 1 is characterized in that it also includes step S0: drilling sampling, surveying, geophysical exploration and monitoring of the slope, determining the depth of the potential sliding surface at each position of the slope by mechanical calculation, obtaining the position and shape of the potential sliding surface, testing the borehole sampling to determine the physical and mechanical parameter values of the slope, and calculating the magnitude of the sliding force, determining the number and range of reinforcement boreholes, and arranging the boreholes. 3. The method for emergency multi-stage reinforcement of slopes according to claim 2 is characterized in that, in step S1, drill holes are set along the direction of slope deformation and failure, the drill hole diameter is 15 to 30 cm, the drill hole spacing is 2.5 to 5 m, the drill hole depth is 1.2 to 1.3 times the thickness of the potential sliding surface, and the hole inclination angle deviation is between plus or minus 3 degrees. 4. The method for emergency multi-stage slope reinforcement according to claim 1 is characterized in that the grouting material is a geopolymer grouting material, specifically a geopolymer prepared by orthogonal test using a composite grouting material based on fly ash, slag powder, metakaolin, sodium silicate solution, calcium oxide expansion agent, sodium hydroxide and deionized water. 5. The method for emergency multi-stage slope reinforcement according to claim 1, characterized in that the circulating refrigerant liquid in step S3 is an antifreeze liquid with a temperature of -20°C to -42°C. 6 . The method for emergency multi-stage slope reinforcement according to claim 1 , wherein the phase change liquid in step S4 is an ionic curing agent. 7. The method for emergency multi-stage slope reinforcement according to claim 1 is characterized in that centering brackets are arranged on the anchor body along the axial direction at intervals of 1.0 to 2.0 m; the anchor body is straight, smooth, degreased and derusted; and the grouting pipe is placed in the borehole together with the anchor body. 8. The method for emergency multi-stage slope reinforcement according to claim 1, characterized in that the anchor rod body and the grouting material form a grouting material anchor rod reinforcement system. 9. The method for emergency multi-stage slope reinforcement according to claim 1, characterized in that the injection port of the phase change liquid pipe is arranged between the U-shaped circulation pipes.