CN111335293A

CN111335293A - Method for improving thermal physical property of soil body around energy pile by utilizing biological grouting

Info

Publication number: CN111335293A
Application number: CN202010107837.1A
Authority: CN
Inventors: 张鹏; 成亮; 杨涛; 高伟; 潘雅静; 王亚文
Original assignee: Jiangsu University; Qingdao University of Technology
Current assignee: Jiangsu University; Qingdao University of Technology
Priority date: 2020-02-21
Filing date: 2020-02-21
Publication date: 2020-06-26

Abstract

The invention discloses a method for improving the thermal physical property of soil around an energy pile by utilizing biological grouting, which comprises the steps of pressing a grouting pipe with a completely closed pipe wall into sand around the energy pile, rotating an inner pipe of the grouting pipe to enable a through hole of the inner pipe to be superposed with a through hole of an outer pipe, injecting microbial liquid or urease solution with urease activity into the sand around the energy pile through the grouting pipe, then injecting mineralized cementing liquid into the sand around the energy pile through the grouting pipe, and setting the reaction time after grouting; wherein the mineralized cementing liquid is a solution containing urea and salt, and the salt is a calcium salt and/or a magnesium salt. The method can solve the problems of low heat exchange efficiency of the energy pile in the weak sandy soil stratum, insufficient bearing capacity of the pile foundation, overlarge sedimentation and the like.

Description

Method for improving thermal physical property of soil body around energy pile by utilizing biological grouting

Technical Field

The invention belongs to the technical field of energy piles, relates to a soil body thermophysical property improving method integrating foundation soil reinforcement treatment and pile soil heat conduction and heat exchange effects, and relates to a method for improving the thermophysical property of soil bodies around energy piles by utilizing biological grouting.

Background

The information in this background section is only for enhancement of understanding of the general background of the invention and is not necessarily to be construed as an admission or any form of suggestion that this information forms the prior art that is already known to a person of ordinary skill in the art.

With the development of science and technology and the increasing living standard of people, the energy required by air conditioning and heating is increasing, however, the traditional energy has higher heating use cost and is easy to cause environmental pollution, which is deviated from the aim of creating green environment by energy conservation and emission reduction at present. The energy pile is a novel ground source heat pump pipe burying form, is an economic, efficient, energy-saving and emission-reducing technology combining a ground source heat pump technology and a building pile foundation, a heat exchange pipe in the ground source heat pump system is buried inside a pile body, the pile plays a role in bearing and exchanging heat at the same time, underground space is saved, shallow geothermal energy is fully utilized, and the energy pile is a real green air conditioner.

The energy pile heat transfer system comprises four parts of rock soil, a pile, a heat exchange pipe and heat exchange liquid, wherein the pile and soil around the pile are used as heat transfer main bodies and need to have better heat transfer performance, and at present, the energy pile mainly improves the heat conduction performance of the pile body by means of methods of improving concrete proportion, adding doping materials, changing pile foundation pipe burying forms and the like, so that the heat exchange efficiency of the energy pile is improved, and the utilization rate of geothermal heat is increased.

However, through the research of the inventor of the invention, the existing method neglects the utilization of the heat conduction performance of the soil body. Meanwhile, the intervention of temperature can cause the energy pile to expand with heat and contract with cold, and the additional axial stress, the additional frictional resistance and the additional axial displacement generated by the pile body can cause the consequences of reduced bearing capacity of the foundation, damaged pile body, damaged upper structure and the like; therefore, the application of the energy pile puts higher requirements on the mechanical property of the soil body around the pile and the foundation of the bearing pile foundation. In addition, the strength, deformation property and soft hardening property of the pile side soil not only affect the performance and magnitude of the pile side frictional resistance, but also affect the performance and magnitude of the bearing capacity of the pile body, and similarly, the type and nature of the pile end bearing layer also directly affect the magnitude and settling amount of the pile end resistance.

Disclosure of Invention

The invention aims to solve the defects in the prior art, in particular to the problems of low heat exchange efficiency, insufficient pile foundation bearing capacity, overlarge sedimentation and the like of an energy pile in a weak sandy soil stratum, and provides a method for improving the thermal physical property of a soil body around the energy pile by utilizing biological grouting.

In order to achieve the purpose, the technical scheme of the invention is as follows:

on the one hand, the application of biological grouting in improving the thermal physical property of soil around the pile of the energy pile is provided.

The invention injects the sand around the pile by biological grouting, utilizes carbonate crystal which is generated by biological induced cementing material and has cementing and filling functions to reinforce the sand around the pile, and simultaneously enlarges the heat transfer path and the heat exchange surface area of sand particles, the heat conductivity coefficient of soil and the hot melting of the soil, thereby improving the heat exchange efficiency of the energy pile.

The invention finds that the problem that sand particles enter a pipe cavity or block a grout outlet exists in the process of pressing the pipe by utilizing biological grouting in the process of improving the thermal physical property of the soil mass around the pile of the energy pile, so that on the other hand, the invention provides a grouting pipe for improving the thermal physical property of the soil mass around the pile of the energy pile, wherein one end of the grouting pipe is closed, the other end of the grouting pipe is used for grouting, the grouting pipe is formed by inserting an inner pipe into an outer pipe, the length of the inner pipe is not less than that of the outer pipe, the outer diameter of the inner pipe is equal to or slightly less than the inner diameter of the outer pipe, a plurality of through holes are formed in the inner pipe and the outer pipe, and one end of the inner pipe is provided with a part for; after the inner pipe is inserted into the outer pipe, the positions of the through holes of the inner pipe and the through holes of the outer pipe can be the same by rotating the inner pipe.

The inner space of the grouting pipe is communicated and sealed with the outside through the through holes of the inner pipe and the outer pipe by utilizing the rotating matching of the inner pipe and the outer pipe, and when the rotating pipe rotates to the same position of the through holes of the inner pipe and the through holes of the outer pipe, grouting can be carried out on soil bodies through the grouting pipe; when the positions of the through holes rotating to the inner pipe and the through holes of the outer pipe are different, sand particles can be prevented from entering the pipe cavity or blocking the slurry outlet in the pipe pressing process.

In order to better solve the problems of low heat exchange efficiency of an energy pile in a weak sandy soil stratum, insufficient bearing capacity of a pile foundation, overlarge sedimentation and the like, the third aspect of the invention is a method for improving the thermal physical properties of the soil body around the energy pile by utilizing biological grouting, and provides the grouting pipe for improving the thermal physical properties of the soil body around the energy pile by utilizing the biological grouting; wherein the mineralized cementing liquid is a solution containing urea and salt, and the salt is calcium salt, magnesium salt or a mixture of the calcium salt and the magnesium salt.

In the invention, microorganisms with urease activity or urease molecules among sand particles fully react with mineralized cementing liquid to generate insoluble or slightly soluble carbonate deposition cementing materials, and the materials are distributed in a multi-particle cluster shape and are distributed at the contact parts of the sand particles, so that a heat transfer path is enlarged, and a larger heat exchange surface area is provided. In addition, the carbonate sediment with the functions of cementation and filling increases cohesive force and an internal friction angle of the sandy soil, so that the strength of the sandy soil, the integral stability of the sandy soil and the friction resistance of the side of the pile are effectively improved.

The invention has the beneficial effects that:

(1) the invention enlarges the heat transfer path of the energy pile system from the angle of soil, improves the heat exchange efficiency of the energy pile and increases the utilization rate of geothermal heat.

(2) The grouting pipe provided by the invention solves the problem that sand particles enter a pipe cavity or block a grout outlet in the pipe pressing process by nesting the inner pipe and the outer pipe.

(3) The invention adopts a biological method, has simple reaction mechanism, strong controllability, small disturbance to soil, less related process parameters, lower implementation difficulty, convenient acquisition of raw materials and low cost.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the invention and together with the description serve to explain the invention and not to limit the invention.

FIG. 1 is a schematic diagram of the main structure of the present invention;

FIG. 2 is a schematic view of the structure of the grouting pipe according to the present invention;

FIG. 3 is a top view of the grout tube of the present invention;

FIG. 4 is a schematic diagram of the main structure of the rotating device according to the present invention;

the energy pile comprises a foundation 1, a foundation 2, an energy pile 3, a grouting pipe 4, a steel pipe (inner pipe) 5, a sleeve (outer pipe), a steel conical head 6, a steel conical head 7, a first grout outlet hole 8, a second grout outlet hole 9, a steel bar 10, a rotating device 11, a ring 12 and a rotating handle.

Detailed Description

It is to be understood that the following detailed description is exemplary and is intended to provide further explanation of the invention as claimed. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments according to the invention. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.

Biological grouting is a soil body reinforcing method, bacteria liquid or direct urease solution and nutrient salt are poured into loose sandy soil, and calcite gel is rapidly precipitated among sand particles by using the induced mineralization of biological urease, so that the physical and mechanical properties of a soil body are improved.

In view of the problems of low heat exchange efficiency of the energy pile in the weak sandy soil stratum, insufficient bearing capacity of the pile foundation, overlarge sedimentation and the like, the invention provides a method for improving the thermal physical property of the soil body around the energy pile by utilizing biological grouting.

The invention provides an application of biological grouting in improving the thermal physical property of soil around an energy pile.

According to the invention, the sand soil around the pile is injected through biological grouting, carbonate crystals with cementation and filling effects generated by inducing a cementing material by using biological urease are used for reinforcing the sand soil around the pile, and meanwhile, the heat transfer path and the heat exchange surface area of sand soil particles, the heat conductivity coefficient of a soil body and the soil body hot melting are enlarged, so that the heat exchange efficiency of the energy pile is improved.

In order to solve the problem that sand particles enter a pipe cavity or block a grout outlet in the pipe pressing process, another embodiment of the invention provides a grouting pipe for improving the thermal physical property of a soil body around an energy pile through biological grouting, wherein one end of the grouting pipe is closed, the other end of the grouting pipe is used for grouting, the grouting pipe is formed by inserting an inner pipe into an outer pipe, the length of the inner pipe is not less than that of the outer pipe, the outer diameter of the inner pipe is equal to or slightly less than the inner diameter of the outer pipe, a plurality of through holes are formed in the inner pipe and the outer pipe, and one end of the inner pipe is provided with a part for enabling the inner pipe to rotate around a central axis; after the inner pipe is inserted into the outer pipe, the positions of the through holes of the inner pipe and the through holes of the outer pipe can be the same by rotating the inner pipe.

The outer diameter of the inner pipe of the grouting pipe is equal to or slightly smaller than the inner diameter of the outer pipe, so that sandy soil particles are prevented from entering the pipe cavity through gaps between the pipes, and the sandy soil particles are prevented from entering the space between the pipes to block the rotation of the inner pipe. Slightly smaller means within 3 mm.

The inner pipe and the outer pipe are both hollow round pipes.

In one or more embodiments of this embodiment, the closed end of the slip casting tube is tapered. The grouting pipe is convenient to press into the soil body around the energy pile.

One end of the inner pipe is provided with a component for enabling the inner pipe to rotate around the central axis, the component can be a handle directly connected to the inner pipe, and the component can be rotating components matched with each other. The rotating cover is rotated, and the inner tube is rotated through the contact of the rotating rod and the inner tube rod. The influence of parts on the pipe pressing process, the grouting process and the like can be avoided. When the number of the inner tube rods and the rotating rods is increased, the rotating amplitude of the rotating cover can be reduced. For example, when the inner tube rod and the rotating rod are both one, the forward and reverse rotation of the inner tube needs to rotate the rotating cover by about 360 degrees; and when the two inner tube rods or the two rotating rods or both the two inner tube rods and the two rotating rods are arranged oppositely, the forward and reverse rotation of the inner tube only needs to rotate the rotating cover by about 180 degrees. When the number of the inner tube rods and the number of the rotating rods are specific and the position relationship is specific, the rotating amplitude of the rotating cover can be reduced. For example, when the shortest distance between the two rotating rods is equal to the diameter of the inner tube rod, the inner tube rod is inserted between the two rotating rods, and the rotation of the inner tube can be realized more conveniently.

In one or more embodiments of this embodiment, the inner tube through holes are arranged in the following manner: 2 symmetrical through holes are formed in the side wall of the upper part of the upper arm of the inner pipe, then 2 symmetrical through holes are formed in positions which are away from the center of the through hole by a set distance and rotate by 90 degrees and 270 degrees respectively, and holes are formed downwards in sequence according to the rule until the bottom of the pipe; the arrangement mode of the through holes of the outer pipe is the same as that of the through holes of the inner pipe.

In one or more embodiments of this embodiment, the inner tube has inner and outer threads at its two ends for matching, and the outer tube has inner and outer threads at its two ends for matching. The length can be conveniently increased according to the requirement.

The invention provides a method for improving the thermal physical property of soil around an energy pile by utilizing biological grouting, the grouting pipe for improving the thermal physical property of the soil around the energy pile is provided, the wall of the grouting pipe is completely sealed, the grouting pipe is pressed into the sand around the energy pile, then the inner pipe of the grouting pipe is rotated to ensure that the through hole of the inner pipe is coincided with the through hole of the outer pipe, biological bacteria liquid or urease solution with urease activity is injected into the sand around the energy pile through the grouting pipe, then mineralized cementing liquid is injected into the sand around the energy pile through the grouting pipe, and the reaction is set for time after the grouting is finished; wherein the mineralized cementing liquid is a solution containing urea and salt, and the salt is calcium salt, magnesium salt or a mixture of the calcium salt and the magnesium salt.

In the invention, organisms or urease among sand particles and mineralized cementing liquid fully react to generate insoluble or slightly soluble carbonate deposition cementing material, and the material is in multi-particle cluster concentrated distribution and is distributed at the contact part of the sand particles, so that a heat transfer path is enlarged and a larger heat exchange surface area is provided. In addition, the carbonate sediment with the functions of cementation and filling increases cohesive force and an internal friction angle of the sandy soil, so that the strength of the sandy soil, the integral stability of the sandy soil and the friction resistance of the side of the pile are effectively improved.

The calcium salt in the present invention means a compound which is soluble in water and has a cation of calcium ion, such as calcium chloride, calcium nitrate, calcium acetate, and the like.

The magnesium salt in the present invention refers to a compound which is soluble in water and has a cation of magnesium ion, such as magnesium chloride, magnesium nitrate, magnesium acetate, and the like.

Examples of the microorganism having urease activity in the present invention include Bacillus basalis.

In one or more embodiments of the embodiment, 4-8 grouting pipes are arranged on the soil body around the energy pile. The number of the grouting pipes among the piles is determined according to the distance between the piles.

In one or more embodiments of the embodiment, the urease activity in the microbial liquid or urease solution with urease activity is 1-30U/mL.

In one or more embodiments of the present disclosure, the injection speed of the microbial liquid or urease solution having urease activity is 10 to 100L/min.

In one or more embodiments of the present disclosure, the concentration of solute in the mineralized cementitious liquid is 0.1-2 mol/L.

In one or more embodiments of this embodiment, the molar ratio of urea to calcium salt to magnesium salt is 10:0 to 10, and the calcium salt and the magnesium salt are not 0 at the same time.

In one or more embodiments of this embodiment, the mineralized cementitious liquid is injected in a volume that is 1-5 times the injection volume of the microbial liquid with urease activity or the urease solution. The relationship of the grouting volume can be determined by grouting flow rate, grouting time and grouting times. For example, if the grouting flow rate and the grouting time are the same, the injection volume ratio of the mineralized cementitious liquid to the microbial liquid with urease activity or the urease solution can be determined through the grouting times. Wherein, the injection frequency of the mineralized and cemented liquid is 1 time, and can also be multiple times. Every time the microbial liquid with urease activity or the urease solution is injected, the reaction is required to set time.

In one or more embodiments of the present disclosure, the reaction time is 12 to 72 hours after the grouting.

In order to make the technical solutions of the present invention more clearly understood by those skilled in the art, the technical solutions of the present invention will be described in detail below with reference to specific embodiments.

Example 1

As shown in fig. 1 to 4, the grouting pipe 3 is used for improving the thermal physical properties of the soil body around the energy pile 2 in the soft sand foundation 1, and has a main structure comprising: the steel pipe comprises a steel pipe 4, a sleeve 5, a steel conical head 6, a first slurry outlet hole 7, a second slurry outlet hole 8, a steel bar 9 and a rotating device 10, wherein the rotating device 10 is formed by welding the steel bar 9, a ring 11 cut from the sleeve and a rotating handle 12. The diameter of the steel pipe 4 is equal to the diameter of the round bottom of the steel conical head 6, the steel pipe 4 is connected with the steel conical head 6 in a welding mode, 2 symmetrical second slurry outlet holes 8 capable of releasing slurry outwards are formed in the side wall of the upper portion of the steel pipe, then 2 symmetrical second slurry outlet holes 8 are formed in positions which are 0.8m away from the center of the hole and rotate 90 degrees and 270 degrees respectively, and holes are formed downwards to the bottom of the pipe in sequence according to the rule; the sleeve 5 is inserted in the steel pipe 4 in a penetrating manner, the length of the sleeve 5 is the same as that of the steel pipe 4, the outer diameter of the sleeve 5 is 2mm smaller than the inner diameter of the steel pipe 4, the side wall of the sleeve 5 is provided with a first slurry outlet hole 7 capable of discharging slurry outwards, and the number, size and position of the openings are the same as those of the slurry outlet holes in the steel pipe. The steel bar 9 with the length of 0.03m is welded at 4 angular points of the inner wall of the sleeve 5, the steel bar 9 with the length of 0.1m is welded at 4 angular points of the inner wall of the ring 11 intercepted on the sleeve, and the steel bar 9 with the length of 0.2m is welded on the side wall of the ring 11 along the axial direction and serves as a rotating handle 12 of the rotating device.

The specific process comprises the following steps:

(1) the rotating device 10 is clamped in the sleeve 5, the rotating handle 12 is rotated to enable the rotating device 10 to drive the sleeve 5 to rotate in the steel pipe 4 until the first slurry outlet hole 7 in the sleeve is coincided with the second slurry outlet hole 8 in the steel pipe, then the rotating handle 12 is rotated by 90 degrees, the second slurry outlet hole 8 in the steel pipe is completely blocked by the inner wall of the sleeve 5, and then the rotating device 10 is taken down.

(2) The grouting pipes 3 are pressed into sandy soil until a pile end bearing layer by adopting a static pipe pressing machine, 4 grouting pipes 3 are distributed around the pile, the number of the grouting pipes 3 among the piles is determined according to the pile spacing, and then the sleeve 5 in the steel pipe 4 is rotated by 90 degrees by using the rotating device 10, so that the first grout outlet 7 and the second grout outlet 8 are superposed, and grout is conveniently injected into a soil body.

(3) And injecting bacillus pasteurii bacterial liquid with the urease activity of 10U/mL into the sleeve 5 by adopting an injection pump, wherein the flow rate is 10L/min, the time is 30 minutes, and the slurry in the sleeve enters the sandy soil through the first slurry outlet 7 and the second slurry outlet 8 in sequence.

(4) And (3) injecting a mixed solution of urea and calcium chloride into the casing 5 by using a grouting pump, wherein the concentration of the urea and the concentration of the calcium chloride are respectively 1 mol/L, the grouting flow rate and the grouting time are consistent with those of the process (3), and finishing a grouting process after waiting for 24 hours. In order to improve the soil strength and the thermodynamic performance to different degrees, multiple grouting is carried out for 16-20 times, and 24 hours are required to be waited after each grouting is finished, so that the reaction is fully finished. The injection of the bacillus pasteurii bacterial solution shown in the procedure (3) was carried out before the 5 th, 10 th and 15 th slip. The microbial bacteria liquid among the sand particles fully reacts with the solution to generate the crystalline calcium carbonate solid phase cementing material which is in multi-particle cluster shape and is intensively distributed and mostly distributed at the contact part of the sand particles, thereby enlarging the heat transfer path and simultaneously providing larger heat exchange surface area. In addition, the calcium carbonate playing a role in cementation and filling increases the cohesive force and the internal friction angle of the sandy soil, so that the strength, the integral stability and the side frictional resistance of the sandy soil are effectively improved.

The soil thermophysical property test data measured by the method of the above example are shown in table 1.

TABLE 1 soil body thermal conductivity and specific heat capacity test results

As can be seen from Table 1, the values of the thermal conductivity and the specific heat capacity of the sample are gradually increased along with the increase of the grouting times, and the grouting can obviously improve the thermal property of the sandy soil. Before and after grouting, the maximum increase of the thermal conductivity coefficient of the sample is 87.4%, and the maximum increase of the specific heat capacity is 159%. The reason for analyzing the increase of the thermal conductivity coefficient is as follows: the mineralized calcium carbonate crystals provide a more efficient heat transfer path as a "thermal bridge" between the sand particles, providing a greater heat transfer surface area than untreated sand exchanged through smaller contact points.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An application of biological grouting in improving the thermal physical property of soil around an energy pile.

2. A grouting pipe for improving the thermal physical property of soil around an energy pile for biological grouting is characterized in that one end of the grouting pipe is closed, the other end of the grouting pipe is used for grouting, the grouting pipe is formed by inserting an inner pipe into an outer pipe, the length of the inner pipe is not less than that of the outer pipe, the outer diameter of the inner pipe is equal to or slightly less than the inner diameter of the outer pipe, a plurality of through holes are formed in the inner pipe and the outer pipe, and one end of the inner pipe is provided with a component for enabling the inner pipe to rotate around a central axis; after the inner pipe is inserted into the outer pipe, the positions of the through holes of the inner pipe and the through holes of the outer pipe can be the same by rotating the inner pipe.

3. The grouting pipe for improving the thermal property of soil around an energy pile for biological grouting of claim 2, wherein the closed end of the grouting pipe is of a conical structure.

4. The grouting pipe for improving the thermal properties of soil around an energy pile as claimed in claim 2, wherein the components comprise at least one inner pipe rod connected to the inner wall of the inner pipe, the axis of the inner pipe rod being parallel to the axis of the inner pipe, and a rotating cover provided with at least one rotating rod engaged with the inner pipe rod.

5. The grouting pipe for improving the thermal property of soil around an energy pile for biological grouting as claimed in claim 2, wherein the inner pipe is provided with internal and external threads at two ends thereof, and the outer pipe is provided with internal and external threads at two ends thereof.

6. A method for improving the thermal physical properties of soil around an energy pile by utilizing biological grouting, which is characterized in that the grouting pipe for improving the thermal physical properties of the soil around the energy pile by utilizing the biological grouting according to any one of claims 2 to 5 is provided; the pipe wall is completely sealed, the grouting pipe is pressed into sand around the energy pile, the inner pipe of the grouting pipe is rotated to enable the through hole of the inner pipe to be coincided with the through hole of the outer pipe, microbial bacteria liquid or urease solution with urease activity is injected into the sand around the energy pile through the grouting pipe, then mineralized cementing liquid is injected into the sand around the energy pile through the grouting pipe, and the reaction is carried out for set time after grouting is completed; wherein the mineralized cementing liquid is a solution containing urea and salt, and the salt is a calcium salt and/or a magnesium salt.

7. The method for improving the thermal physical properties of the soil body around the energy pile by using biological grouting according to claim 6, wherein the urease activity in the microbial liquid or urease solution with urease activity is 1-30U/mL;

or the injection speed of the microbial liquid with urease activity or the urease solution is 10-100L/min.

8. The method for improving the thermal physical property of the soil body around the energy pile by utilizing the biological grouting as claimed in claim 6, wherein the concentration of solute in the mineralized cementing liquid is 0.1-2 mol/L;

or the molar ratio of the urea to the calcium salt to the magnesium salt is 10: 0-10, and the molar ratio of the calcium salt to the magnesium salt is not 0 at the same time.

9. The method for improving the thermal properties of the soil body around the energy pile by using biological grouting according to claim 6, wherein the injection volume of the mineralized cementing liquid is 1-5 times of the injection volume of the microbial liquid with urease activity or the urease solution.

10. The method for improving the thermal physical property of the soil body around the pile of the energy pile by using the biological grouting as claimed in claim 6, wherein the reaction lasts for 12-72 hours after the grouting is finished.