Phase change temperature control composite mortar and phase change temperature control anchor rod construction method

Abstract

The invention discloses phase change temperature control composite mortar and a phase change temperature control anchor rod construction method, and belongs to the technical field of underground engineering surrounding rock supporting. The phase change temperature control composite mortar comprises cement, fine sand, water, a phase change material and heat conduction powder; the construction method comprises the following steps: drilling an excavated bed rock to form an anchor rod drill hole; a sectional type anchor rod is arranged in the anchor rod drill hole in a penetrating mode, wherein the sectional type anchor rod is divided into an anchoring section and a non-anchoring section; cement mortar is used for grouting the anchoring section through a grouting pipe, and grouting is stopped when the interface between the anchoring section and the non-anchoring section is reached; and after the slurry of the anchoring section is hardened, the phase-change temperature-control composite mortar is heated, then the phase-change temperature-control composite mortar is injected into the non-anchoring section through the grouting pipe, the single-hole grouting pressure reaches the designed final pressure, grouting continues for a period of time, and then grouting is ended. The method can adapt to frequent changes of surrounding rock temperature, and surrounding rock damage and anchor rod failure caused by temperature stress accumulation of surrounding rock are avoided.

Description

Technical Field

[0001] The present invention relates to a phase change temperature control composite mortar and a construction method of a phase change temperature control bolt, belonging to the technical field of surrounding rock support in underground engineering. Background Art

[0002] As an important part of a compressed air energy storage power station, an underground gas storage plays a key role in energy storage and peak shaving. However, during the operation of the gas storage, due to the rapid cyclic charging and discharging of compressed air, the temperature of the underground surrounding rock will change significantly. Such temperature fluctuations will not only cause changes in the physical and mechanical properties of the surrounding rock, but may also lead to cracking and damage of the surrounding rock, thus increasing the safety risks of the gas storage. Therefore, how to effectively control the temperature fluctuations of the surrounding rock and prevent the damage of the surrounding rock caused by temperature stress has become a key problem to be solved urgently in the gas storage project.

[0003] In underground engineering, as an important support structure, bolts are widely used for reinforcement of surrounding rock stability. The traditional bolt construction technology mainly combines bolts with the surrounding rock through grouting materials to form an anchoring force, thereby improving the stability of the surrounding rock. However, the existing grouting materials and construction methods usually only focus on the improvement of mechanical properties, while ignoring the influence of temperature fluctuations of the surrounding rock on the stability of bolts and the surrounding rock. Especially in the gas storage project, due to the frequent change of the surrounding rock temperature, the traditional bolt system is difficult to effectively adapt to this dynamic environment, resulting in the accumulation of temperature stress in the surrounding rock, and further causing damage to the surrounding rock and failure of the bolts. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the defects of the prior art and provide a phase change temperature control composite mortar and a construction method of a phase change temperature control bolt, which can adapt to the frequent change of the surrounding rock temperature and avoid the damage of the surrounding rock and the failure of the bolts caused by the accumulation of temperature stress in the surrounding rock.

[0005] To solve the above technical problem, the technical solution adopted by the present invention is as follows:

[0006] In a first aspect, the present invention provides a phase change temperature control composite mortar, comprising cement, fine sand, water, a phase change material and a heat conduction powder.

[0007] By mass, cement: fine sand: water: phase change material: heat conduction powder = 0.8 - 1.2: 1.5 - 2.5: 0.4 - 0.6: 0.02 - 0.04: 0.01.

[0008] The phase change material includes organic paraffin or inorganic hydrated salt; the cement is Portland cement; the particle size of the fine sand is less than 0.35 mm; the heat conduction powder includes copper powder or graphite powder.

[0009] The inorganic hydrated salt includes sodium sulfate decahydrate or disodium hydrogen phosphate dodecahydrate.

[0010] In a second aspect, the present invention provides a construction method for a phase change temperature-controlled bolt, using the above-mentioned phase change temperature-controlled composite mortar, which includes the following steps:

[0011] Step a: Drill the excavated bedrock to form a bolt hole.

[0012] Step b: Insert the segmented bolt into the bolt hole. The segmented bolt is divided into an anchorage section and a non-anchorage section, and grouting pipes are respectively installed at the ends of the anchorage section and the non-anchorage section of the bolt.

[0013] Step c: Grout the anchorage section with cement mortar through the grouting pipe. The grouting pipe is slowly withdrawn as the grouting progresses and stops grouting when reaching the interface between the anchorage section and the non-anchorage section.

[0014] Step d: After the grout in the anchorage section hardens, heat the phase change temperature-controlled composite mortar, and then inject the phase change temperature-controlled composite mortar into the non-anchorage section through the grouting pipe. The grouting pipe is slowly withdrawn as the grouting progresses. Stop grouting after the single-hole grouting pressure reaches the designed final pressure and continues grouting for a period of time.

[0015] Step e: After grouting, arrange a steel mesh on the sprayed rock surface at the opening of the bolt hole, and then spray concrete on the steel mesh.

[0016] In step a, the diameter of the bolt hole is 40 - 60 mm and the depth is 2 - 5 m.

[0017] In step b, the surface of the anchorage section is pre-coated with an adhesive; the distance from the outlet position of the grouting pipe corresponding to the anchorage section to the bottom of the bolt hole is 100 - 200 mm; the distance from the outlet position of the grouting pipe corresponding to the non-anchorage section to the interface between the anchorage section and the non-anchorage section is 100 - 200 mm.

[0018] In step c, the grouting pressure ≥ 1 Mpa; the preparation process of the cement mortar is: put ordinary Portland cement, fine sand and water into the on-site construction mixer, stir for 4 - 6 min, and set the rotation speed of the mixer to 140 - 160 r / min.

[0019] In step d, the grouting pressure ≥ 1 Mpa; the preparation process of the phase change temperature-controlled composite mortar is: put the phase change material, cement, fine sand and heat-conducting powder into the on-site construction mixer, stir for 8 - 12 min, then add water and stir for 4 - 6 min, set the rotation speed of the mixer to 140 - 160 r / min to make the mixture evenly stirred; the time for continuing grouting when the single-hole grouting pressure reaches the designed final pressure is 8 - 12 min.

[0020] In step e, the size of the steel mesh is φ8, and the spacing is 200×200 mm. The concrete spraying process is as follows: the rock surface to be sprayed is pre-wetted with pressurized water. The first spraying thickness of the concrete is 50 mm. After the concrete begins to set, another 50 mm of concrete is sprayed.

[0021] The beneficial effects of the present invention: The present invention provides a phase change temperature control composite mortar and a construction method of a phase change temperature control bolt. The phase change temperature control composite mortar includes cement, fine sand, water, a phase change material, and a heat conduction powder. The phase change material can regulate the temperature fluctuation of the surrounding rock by absorbing or releasing heat, enabling the prepared phase change temperature control composite mortar to have good heat regulation performance, controlling the surrounding rock temperature within an appropriate range, being able to adapt to the frequent changes in the surrounding rock temperature, avoiding the accumulation of temperature stress in the surrounding rock and causing damage to the surrounding rock and bolt failure. In addition, the heat conduction powder significantly improves the heat transfer efficiency, ensuring a rapid response to temperature changes;

[0022] The present invention also adopts a segmented bolt design combined with a grouting process, using cement mortar and phase change temperature control composite mortar for the anchorage section and non-anchorage section of the bolt respectively, realizing differential treatment of the bolt in different sections, enhancing the anchorage effect, and making full use of the large number of bolt drilling and grouting processes existing in the surrounding rock of the underground chamber to achieve dual control of the surrounding rock temperature and mechanical properties. This innovative design can not only effectively prevent the excessive temperature variation of the surrounding rock but also significantly improve the support effect of the bolt, providing a reliable technical guarantee for the safe operation of the gas storage cavern. In addition, the construction process makes full use of the large number of systematic bolt drilling and grouting processes existing in the surrounding rock of the underground chamber, optimizing the construction process and reducing the project cost. Description of the Drawings

[0023] Figure 1 It is a structural schematic diagram of a phase change temperature control bolt in the invention;

[0024] Figure 2 It is a flow chart of a construction method of a phase change temperature control bolt in the invention;

[0025] The reference numerals in the drawings are as follows: 1 - anchorage section; 2 - non-anchorage section; 3 - bolt steel bar; 4 - drill bit; 5 - connecting sleeve; 6 - grout stopper; 7 - backing plate; 8 - washer; 9 - nut; 10 - surrounding rock; 11 - grouting pipe. Detailed Embodiments

[0026] The present invention will be further described below with reference to the drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention and cannot be used to limit the protection scope of the present invention.

[0027] Embodiment 1

[0028] As Figure 1As shown in the figure, the phase change temperature control bolt structure in the present invention is composed of a bolt head, an anchorage section 1, and a non-anchorage section 2. The bolt head includes a turning head 4, a bolt steel bar 3, a connecting sleeve 5, a backing plate 7, a washer 8, and a nut 9. The bolt steel bar 3 is threadedly connected to the nut 9, and the nut 9 is fixed on the washer 8 and the backing plate 7, and the backing plate 7 is fixed outside the surrounding rock 10. The anchorage section 1 is an anchor body formed by bonding the bolt steel bar 3 with cement mortar, which is a section near the bottom of the drill hole. Specifically, the bolt steel bar 3 in the anchorage section 1 can be pre-coated with a high-strength adhesive on the surface to enhance the anchoring effect. The non-anchorage section 2 is a temperature control non-anchor body formed by bonding the bolt steel bar 3 with phase change temperature control composite mortar, and a slurry stopper 6 is provided at the drill hole.

[0029] The present invention discloses a phase change temperature control composite mortar, which is used in the construction process of the above bolt structure. Specifically, the phase change temperature control composite mortar is prepared from a phase change material, cement, fine sand, a heat conduction powder, and water. By mass, cement: fine sand: water: phase change material: heat conduction powder = 1: 2: 0.5: 0.03: 0.01. The thermal conductivity of the phase change temperature control composite mortar can reach 1.85 W / (m·K), the 28-day compressive strength can reach 13.5 MPa, and the phase change temperature range is 0 - 50 °C. The phase change material can be organic paraffin or inorganic hydrated salt (phase change material: sodium sulfate decahydrate (Na2SO4·10H2O), phase change temperature is about 32 °C, latent heat value is high (about 190 kJ / kg); disodium hydrogen phosphate dodecahydrate (Na2HPO4·12H2O): phase change temperature is about 35 °C), and in this embodiment, organic paraffin is preferably used; the cement is ordinary Portland cement; the particle size of the fine sand is less than 0.35 mm; the heat conduction powder is copper powder or graphite powder, and in this embodiment, copper powder is preferably used to ensure its temperature regulation function in the operating environment of the gas storage reservoir.

[0030] As Figure 2 shown, the present invention provides a phase change temperature control bolt construction method, which uses the above phase change temperature control composite mortar to prevent the damage and failure of the surrounding rock caused by temperature stress, and includes the following steps:

[0031] Step 1: Drill the excavated bedrock. The hole diameter is 40 - 60 mm, and the depth is 2 - 5 m. The specific dimensions can be adjusted according to the actual reinforcement requirements.

[0032] Step 2: Insert the segmented bolt into the drill hole. The bolt is divided into an anchorage section and a non-anchorage section. The surface of the anchorage section is provided with self-locking threads or pre-coated with a high-strength adhesive to enhance the anchoring effect. Grouting pipes are respectively installed at the ends of the anchorage section and the non-anchorage section of the bolt. The distance from the outlet position of the grouting pipe corresponding to the anchorage section to the bottom of the bolt drill hole is 100 - 200 mm; the distance from the outlet position of the grouting pipe corresponding to the non-anchorage section to the interface between the anchorage section and the non-anchorage section is 100 - 200 mm.

[0033] Step 3: Place ordinary Portland cement, fine sand, and water in a on-site construction mixer, stir for 5 min, set the mixer speed at 150 r / min to obtain M30 cement, and use the M30 cement mortar to grout the anchorage section. The grouting pressure should be ≥1 MPa, and stop grouting when reaching the interface between the anchorage section and the non-anchorage section.

[0034] Step 4: Place the phase change material, cement, fine sand, and heat conduction powder in a on-site construction mixer, stir for 10 min, then add water and stir for 5 min. Set the mixer speed at 150 r / min to make the mixture evenly stirred to obtain the phase change temperature control composite mortar. After the slurry in the anchorage section hardens, heat the well-stirred phase change temperature control composite mortar and grout the non-anchorage section through the grouting pipe. The grouting pressure should also be ≥1 MPa. Slowly withdraw the grouting pipe along with the grouting speed. The grouting for a single hole can end when the designed final pressure is reached and grouting continues for more than 10 minutes.

[0035] Step 5: After grouting is completed, arrange a Φ8 steel mesh with a spacing of 200*200 mm to fix the anchor rod. Spray concrete, and pre-wet the rock surface to be sprayed with pressurized water. Spray in two times. The first spray thickness of the concrete is about 50 mm. After the concrete begins to set, spray another 50 mm of concrete. At this time, the production and construction operation of the phase change temperature control anchor rod are completed.

[0036] The phase change temperature control composite mortar prepared in the present invention can form an anchor rod temperature control layer on the anchor rod, adjust the temperature fluctuation of the surrounding rock by absorbing or releasing heat, so as to achieve the characteristic of temperature regulation. Applying the phase change material to the grouting material can effectively improve the temperature environment of the surrounding rock and reduce the adverse effects of temperature fluctuations on the surrounding rock. At the same time, the heat conduction powder improves the heat transfer efficiency. Combined with the segmented structure design of the anchor rod, making full use of the large number of systematic anchor rod drilling and grouting processes existing in the surrounding rock of the underground chamber, realizing the dual control of the temperature and mechanical properties of the surrounding rock, preventing the temperature variation range of the surrounding rock from being too large during operation, and thus controlling the damage caused by temperature stress in the surrounding rock.

[0037] Example 2

[0038] As Figure 1 shown, the structure of the phase change temperature control anchor rod in the present invention consists of an anchor rod head, an anchorage section 1, and a non-anchorage section 2. Among them, the anchor rod head includes a turning head 4, an anchor rod steel bar 3, a connecting sleeve 5, a backing plate 7, a washer 8, and a nut 9. The anchor rod steel bar 3 is threadedly connected to the nut 9, and the nut 9 is fixed on the washer 8 and the backing plate 7, and the backing plate 7 is fixed outside the surrounding rock 10. The anchorage section 1 is an anchor body formed by the bonding of the anchor rod steel bar 3 and the cement mortar, which is a section near the bottom of the drill hole. Specifically, the surface of the anchor rod steel bar 3 in the anchorage section 1 can be pre-coated with a high-strength binder to strengthen the anchoring effect. The non-anchorage section 2 is a temperature control non-anchor body formed by the bonding of the anchor rod steel bar 3 and the phase change temperature control composite mortar, and a grout stopper 6 is provided at the drill hole.

[0039] The present invention discloses a phase change temperature control composite mortar, which is used in the construction process of the above-mentioned anchor structure. Specifically, the phase change temperature control composite mortar is prepared from a phase change material, cement, fine sand, a heat conduction powder, and water. By mass, cement: fine sand: water: phase change material: heat conduction powder = 0.8: 2.5: 0.4: 0.04: 0.01. The thermal conductivity of the phase change temperature control composite mortar can reach 1.85 W / (m·K), the 28-day compressive strength can reach 13.5 MPa, and the phase change temperature range is 0 to 50 °C. The phase change material can be organic paraffin or inorganic hydrated salt (phase change material: sodium sulfate decahydrate (Na2SO4·10H2O), phase change temperature is about 32 °C, latent heat value is high (about 190 kJ / kg); disodium hydrogen phosphate dodecahydrate (Na2HPO4·12H2O): phase change temperature is about 35 °C), and sodium sulfate decahydrate is preferably used in this embodiment; the cement is ordinary Portland cement; the particle size of the fine sand is less than 0.35 mm; the heat conduction powder is copper powder or graphite powder, and graphite powder is preferably used in this embodiment to ensure its temperature regulation function in the operating environment of the gas storage reservoir.

[0040] As Figure 2 shown, the present invention provides a phase change temperature control anchor construction method, which uses the above-mentioned phase change temperature control composite mortar to prevent surrounding rock damage and failure caused by temperature stress, and includes the following steps:

[0041] Step 1: Drill the excavated bedrock. The hole diameter is 40 to 60 mm, and the depth is 2 to 5 m. The specific dimensions can be adjusted according to the actual reinforcement requirements.

[0042] Step 2: Insert the segmented anchor into the drill hole. The anchor is divided into an anchoring section and a non-anchoring section. The surface of the anchoring section is provided with self-locking threads or pre-coated high-strength adhesive to enhance the anchoring effect. Grouting pipes are respectively installed at the ends of the anchoring section and the non-anchoring section of the anchor. The distance from the outlet position of the grouting pipe corresponding to the anchoring section to the bottom of the anchor drill hole is 100 to 200 mm; the distance from the outlet position of the grouting pipe corresponding to the non-anchoring section to the interface between the anchoring section and the non-anchoring section is 100 to 200 mm.

[0043] Step 3: Place ordinary Portland cement, fine sand, and water in the on-site construction mixer and stir for 4 minutes. Set the rotation speed of the mixer to 160 r / min to obtain M30 cement. Use M30 cement mortar to grout the anchoring section. The grouting pressure should be ≥1 MPa, and stop grouting when reaching the interface between the anchoring section and the non-anchoring section.

[0044] Step 4: Place the phase change material, cement, fine sand, and heat conduction powder into the on-site construction mixer, stir for 8 min, then add water and stir for 4 min. Set the rotation speed of the mixer to 160 r / min to make the mixture evenly stirred, and obtain the phase change temperature control composite mortar. After the grout in the anchorage section hardens, heat the well-stirred phase change temperature control composite mortar and grout the non-anchorage section through the grouting pipe. The grouting pressure should also be ≥1 MPa. The grouting pipe is slowly withdrawn along with the grouting speed. When the single-hole grouting pressure reaches the design final pressure and continues grouting for more than 10 minutes, the grouting can be ended.

[0045] Step 5: After the grouting is completed, arrange the Φ8 steel mesh with a spacing of 200*200 mm to fix the anchor rod. Spray concrete, and pre-wet the rock surface to be sprayed with pressurized water. Spray in two times. The thickness of the first spray of concrete is about 50 mm. After the concrete begins to set, spray 50 mm of concrete again. At this time, the production and construction operation of the phase change temperature control anchor rod are completed.

[0046] The phase change temperature control composite mortar prepared in the present invention can form an anchor rod temperature control layer on the anchor rod, and adjust the temperature fluctuation of the surrounding rock by absorbing or releasing heat, so as to achieve the characteristic of temperature regulation. Applying the phase change material to the grouting material can effectively improve the temperature environment of the surrounding rock and reduce the adverse effects of temperature fluctuation on the surrounding rock. At the same time, the heat conduction powder improves the heat transfer efficiency. Combined with the segmented structure design of the anchor rod, it makes full use of the large number of systematic anchor rod drilling and grouting processes existing in the surrounding rock of the underground chamber to achieve dual control of the temperature and mechanical properties of the surrounding rock, prevent the temperature change range of the surrounding rock from being too large during operation, and thus control the damage caused by temperature stress in the surrounding rock.

[0047] Example 3

[0048] As Figure 1 shown, the phase change temperature control anchor rod structure in the present invention is composed of an anchor rod head, an anchorage section 1, and a non-anchorage section 2. The anchor rod head includes a turning head 4, an anchor rod steel bar 3, a connecting sleeve 5, a backing plate 7, a washer 8, and a nut 9. The anchor rod steel bar 3 is threadedly connected to the nut 9, and the nut 9 is fixed on the washer 8 and the backing plate 7, and the backing plate 7 is fixed outside the surrounding rock 10. The anchorage section 1 is an anchor body formed by the bonding of the anchor rod steel bar 3 and cement mortar, which is a section near the bottom of the drill hole. Specifically, the anchor rod steel bar 3 in the anchorage section 1 can be pre-coated with a high-strength bonding agent on the surface to strengthen the anchoring effect. The non-anchorage section 2 is a temperature control non-anchor body formed by the bonding of the anchor rod steel bar 3 and the phase change temperature control composite mortar, and a grout stopper 6 is provided at the drill hole.

[0049] The present invention discloses a phase change temperature control composite mortar, which is used in the construction process of the above-mentioned bolt structure. Specifically, the phase change temperature control composite mortar is prepared from a phase change material, cement, fine sand, a heat conduction powder, and water. By mass, cement: fine sand: water: phase change material: heat conduction powder = 1.2: 1.5: 0.6: 0.02: 0.01. The thermal conductivity of the phase change temperature control composite mortar can reach 1.85 W / (m·K), the 28-day compressive strength can reach 13.5 MPa, and the phase change temperature range is 0 to 50 °C. The phase change material can be organic paraffin or inorganic hydrated salt (phase change material: sodium sulfate decahydrate (Na2SO4·10H2O), phase change temperature is about 32 °C, latent heat value is high (about 190 kJ / kg); disodium hydrogen phosphate dodecahydrate (Na2HPO4·12H2O): phase change temperature is about 35 °C). In this embodiment, disodium hydrogen phosphate dodecahydrate is preferably used; the cement is ordinary Portland cement; the particle size of the fine sand is less than 0.35 mm; the heat conduction powder is copper powder or graphite powder. In this embodiment, copper powder is preferably used to ensure its temperature control effect in the operating environment of the gas storage reservoir.

[0050] As Figure 2 shown, the present invention provides a phase change temperature control bolt construction method, which uses the above-mentioned phase change temperature control composite mortar to prevent surrounding rock damage and failure caused by temperature stress, and includes the following steps:

[0051] Step 1: Drill the excavated bedrock. The hole diameter is 40 to 60 mm, and the depth is 2 to 5 m. The specific dimensions can be adjusted according to actual reinforcement requirements.

[0052] Step 2: Insert the segmented bolt into the drill hole. The bolt is divided into an anchorage section and a non-anchorage section. The surface of the anchorage section is provided with self-locking threads or pre-coated high-strength adhesive to enhance the anchorage effect. Grouting pipes are respectively installed at the ends of the anchorage section and the non-anchorage section of the bolt. The distance from the outlet position of the grouting pipe corresponding to the anchorage section to the bottom of the bolt drill hole is 100 to 200 mm; the distance from the outlet position of the grouting pipe corresponding to the non-anchorage to the interface between the anchorage section and the non-anchorage section is 100 to 200 mm.

[0053] Step 3: Place ordinary Portland cement, fine sand, and water in the on-site construction mixer and stir for 6 minutes. Set the rotation speed of the mixer to 140 r / min to obtain M30 cement. Use M30 cement mortar to grout the anchorage section. The grouting pressure should be ≥1 MPa, and stop grouting when reaching the interface between the anchorage section and the non-anchorage section.

[0054] Step 4: Place the phase change material, cement, fine sand, and heat-conducting powder into the on-site construction mixer, stir for 12 min, then add water and stir for 6 min. Set the rotation speed of the mixer to 140 r / min to make the mixture evenly stirred, and obtain the phase change temperature-controlled composite mortar. After the grout in the anchorage section hardens, heat the well-stirred phase change temperature-controlled composite mortar and grout the non-anchorage section through the grouting pipe. The grouting pressure should also be ≥1 MPa. The grouting pipe is slowly withdrawn along with the grouting speed. The grouting can be ended when the single-hole grouting pressure reaches the designed final pressure and continues grouting for more than 10 minutes.

[0055] Step 5: After the grouting is completed, arrange the Φ8 steel mesh with a spacing of 200*200 mm to fix the bolt. Spray concrete, and pre-wet the rock surface to be sprayed with pressure water. Spray in two times. The thickness of the first spray of concrete is about 50 mm. After the concrete begins to set, spray 50 mm of concrete again. At this time, the production and construction operation of the phase change temperature-controlled bolt are completed.

[0056] The phase change temperature-controlled composite mortar prepared in the present invention can form a bolt temperature control layer on the bolt, regulate the temperature fluctuation of the surrounding rock by absorbing or releasing heat, so as to achieve the characteristic of temperature regulation. Applying the phase change material to the grouting material can effectively improve the temperature environment of the surrounding rock and reduce the adverse impact of temperature fluctuation on the surrounding rock. At the same time, the heat-conducting powder improves the heat transfer efficiency. Combined with the segmented structure design of the bolt, making full use of the large number of systematic bolt drilling and grouting processes existing in the surrounding rock of the underground chamber, realizing the dual control of the temperature and mechanical properties of the surrounding rock, preventing the temperature variation range of the surrounding rock from being too large during operation, and thus controlling the damage caused by temperature stress in the surrounding rock.

[0057] The above is only the preferred implementation manner of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can still be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A phase change temperature control composite mortar, characterized in that: It includes cement, fine sand, water, phase change material and heat conduction powder.

2. The phase change temperature control composite mortar according to claim 1, wherein: By mass, cement: fine sand: water: phase change material: heat conduction powder = 0.8~1.2: 1.5~2.5: 0.4~0.6: 0.02~0.04: 0.

01.

3. The phase change temperature control composite mortar according to claim 1, characterized in that: The phase change material includes organic paraffin or inorganic hydrated salt; the cement is Portland cement; the particle size of the fine sand is less than 0.35mm; the heat conduction powder includes copper powder or graphite powder.

4. The phase change temperature control composite mortar according to claim 3, characterized in that: The inorganic hydrated salt includes sodium sulfate decahydrate or disodium hydrogen phosphate dodecahydrate.

5. A construction method of a phase change temperature-controlled bolt, using the phase change temperature-controlled composite mortar according to any one of claims 1 to 4, characterized in that: It includes the following steps: Step a, drill the excavated bedrock to form an anchor rod hole. Step b, insert the segmented anchor rod into the anchor rod hole. The segmented anchor rod is divided into an anchorage section and a non-anchorage section, and grouting pipes are installed at the ends of the anchorage section and the non-anchorage section of the anchor rod respectively. Step c, grout the anchorage section with cement mortar through the grouting pipe. The grouting pipe is slowly withdrawn as the grouting progresses and stops grouting when reaching the interface between the anchorage section and the non-anchorage section. Step d, after the grout in the anchorage section hardens, heat the phase change temperature control composite mortar, and then inject the phase change temperature control composite mortar into the non-anchorage section through the grouting pipe. The grouting pipe is slowly withdrawn as the grouting progresses. Stop grouting after the single-hole grouting pressure reaches the design final pressure and continues grouting for a period of time. Step e, after grouting is completed, arrange a steel mesh on the rock spraying surface at the opening of the anchor rod hole, and then spray concrete on the steel mesh.

6. The construction method of the phase change temperature-controlled anchor rod according to claim 5, characterized in that: In step a, the aperture of the anchor rod hole is 40~60mm and the depth is 2~5m.

7. The construction method of the phase change temperature-controlled bolt according to claim 5, characterized in that: In step b, the surface of the anchorage section is pre-coated with an adhesive; the distance from the outlet position of the grouting pipe corresponding to the anchorage section to the bottom of the anchor rod hole is 100~200mm; the distance from the outlet position of the grouting pipe corresponding to the non-anchorage section to the interface between the anchorage section and the non-anchorage section is 100~200mm.

8. The construction method of the phase change temperature-controlled anchor rod according to claim 5, characterized in that: In step c, the grouting pressure ≥ 1Mpa; the preparation process of the cement mortar is: put ordinary Portland cement, fine sand and water into the on-site construction mixer and stir for 4~6min, and set the rotation speed of the mixer to 140~160r / min.

9. The construction method of the phase change temperature-controlled bolt according to claim 5, characterized in that: In step d, the grouting pressure ≥ 1Mpa; the preparation process of the phase change temperature control composite mortar is: put the phase change material, cement, fine sand and heat conduction powder into the on-site construction mixer and stir for 8~12min, then add water and stir for 4~6min, and set the rotation speed of the mixer to 140~160r / min to make the mixture evenly stirred; the time for continuing grouting when the single-hole grouting pressure reaches the design final pressure is 8~12min.

10. The construction method of the phase change temperature-controlled anchor rod according to claim 5, characterized in that: In step e, the size of the steel mesh is φ8 and the spacing is 200×200mm. The concrete spraying process is: pre-wet the sprayed rock surface with pressure water, the thickness of the first sprayed concrete is 50mm, and after the concrete begins to set, spray 50mm of concrete again.

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