Well cementation process for slurry conveying hole of coal mine tunnel

Abstract

The invention discloses a coal mine tunnel slurry conveying hole well cementation process which comprises the following steps: firstly, in a to-be-well-cementation area of a coal mine tunnel, performing all-directional flushing on a slurry conveying hole by using a high-pressure water jet device to remove rock debris and coal cinder on a hole wall, performing preliminary roughening treatment on the hole wall, and performing well cementation in the pretreated slurry conveying hole, a chemical grouting method is adopted to inject a composite grouting material containing nano silica sol and acrylate emulsion, cement, fly ash, silica fume, a water reducing agent, an early strength agent and water are mixed and stirred according to a certain proportion to prepare well cementation slurry, and the prepared well cementation slurry is injected into a slurry conveying hole subjected to hole wall reinforcement and anti-seepage treatment through a grouting pump. In a word, according to the method, the well cementation quality and stability of the slurry conveying hole of the coal mine roadway are remarkably improved through multi-link fine operation, and the method has the advantages of being high in construction efficiency, full in resource utilization, high in adaptability and convenient to maintain.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of coal mine roadway construction, in particular to a coal mine roadway slurry conveying hole well cementation process. BACKGROUND

[0002] With the continuous development of China's coal industry, the requirements for drilling are gradually increasing, so in actual work, it is urgent to introduce new methods, equipment and technologies, appropriately learn from advanced methods, accelerate the optimization and upgrading pace of drilling technology, and turn technology into favorable conditions to further ensure the exploration effect and guide coal mine production work. It has very positive significance.

[0003] At the same time, the roadway in the coal mine is the core component of the underground mining engineering of the coal mine, which refers to the general term of various passages and chambers drilled in the underground coal (rock) layer. They are the "blood network" connecting the ground and the underground coal mining working face, and connecting various coal mining working faces, and are the spatial basis for the production, transportation, ventilation, drainage, pedestrian activities, etc. of the whole mine. In the current coal mining process, the stability of the roadway is crucial to ensure production safety and improve mining efficiency. The reasonable design, scientific construction and effective maintenance of the roadway are directly related to the production efficiency, safety status and economic benefits of the coal mine. Its excavation, support and maintenance are also important fields for continuous research and development in coal mining technology. As an important part of coal mine roadway support and reinforcement, the role of slurry conveying hole is to inject slurry (cement-based, chemical slurry, etc.) into the surrounding rock crack or specific layer to improve the mechanical properties of the rock mass and block the seepage channel, thereby improving the stability and safety of the roadway. The well cementation quality directly affects the overall stability and service life of the roadway, and is also very important to the entire coal mining process.

[0004] The traditional well cementation process has many problems in slurry conveying hole construction, such as low construction efficiency, insufficient positioning accuracy and prone to in-hole accidents, etc. These problems limit the mining of the mine. At present, there is an advanced targeted drilling technology that combines geological exploration data to optimize the construction process to provide the construction efficiency and accuracy of slurry drilling. It can effectively and conveniently manage gas, prevent water inrush and reinforce surrounding rock in coal mines, but there are still many problems in its use process, especially in the pretreatment stage, there are problems of poor flushing effect and no accurate maintenance, which seriously affect the entire slurry drilling construction process, and cannot guarantee the normal progress of targeted accurate construction.

[0005] The current slurry hole pretreatment usually adopts a simple flushing method, which cannot effectively remove the impurities such as rock debris and coal cinder on the hole wall, and the roughening treatment degree of the hole wall is limited, so that the bonding area between the hole wall and the cementing material is insufficient, the bonding strength is low, the cementing layer is prone to delamination from the hole wall, the cementing quality is affected, the traditional grouting material is mainly single component or simple mixed slurry, the permeability, strength and anti-seepage performance of the traditional grouting material are difficult to meet the cementing requirements under complex geological conditions, and the traditional cementing process mainly adopts natural curing, so that the curing time and temperature are difficult to accurately control, the cementing material is not fully hydrated and hardened, the cementing layer strength develops slowly, the design requirements cannot be met in time, and the safety risk in the roadway construction and use process is increased.

[0006] Therefore, a coal mine roadway slurry hole cementing process is urgently needed to solve the problems of easy delamination of hole wall, single component of grouting material, backward curing method, low cementing effect and high safety risk. SUMMARY

[0007] Therefore, a coal mine roadway slurry hole cementing process is urgently needed to solve the problems of easy delamination of hole wall, single component of grouting material, backward curing method, low cementing effect and high safety risk.

[0008] In order to achieve the above technical purposes, the specific technical scheme adopted by the present application is: A coal mine roadway slurry hole cementing process, comprising the following steps: S1, in the coal mine roadway to be fixed well area, using high pressure water jet device to flush the slurry hole all directions, remove the hole wall of coal slag and rock debris, at the same time, the hole wall is preliminary roughened, increase the bonding area of hole wall and subsequent well cementing material; the specific process of slurry hole flushing is: the high pressure water jet device is moved to the appropriate position near the slurry hole, and the equipment is stable, one end of the high pressure water jet pipeline is connected with the high pressure water pump, the other end is slowly inserted into the slurry hole, until the predetermined flushing depth is reached, the high pressure water pump is started, the pressure is gradually increased to the set initial value, in the process of pressure regulation, the running state of the equipment and the reading of the pressure gauge are closely observed, to ensure that the pressure is stable in the set range, the operator controls the nozzle to flush according to the set moving and rotating speed, in the process of flushing, the flushing effect of the hole wall is observed, such as whether the rock debris and coal slag are flushed out, the roughness degree of the hole wall, etc., if the flushing is not ideal, the pressure, the distance between the nozzle and the hole wall and other parameters can be adjusted, for different depth and position of the slurry hole, the way of segmented flushing is adopted, in the process of flushing, the wear condition of the pipeline and nozzle is checked regularly, and it is replaced in time, when the slurry hole flushing is completed, the pressure of the high pressure water jet is gradually reduced, until the high pressure water pump is closed, the high pressure water jet pipeline is slowly pulled out from the slurry hole, and the pipeline and nozzle are cleaned, to remove the residual rock debris and coal slag, to prevent blockage.

[0009] S2, in the pre-treatment of the slurry hole, using chemical grouting method injection containing nano-silica sol and acrylate emulsion composite grouting material, the mass fraction of nano-silica sol is 5%~10%, the mass fraction of acrylate emulsion is 3%~8%, the grouting pressure is controlled in 1-3MPa, the composite grouting material is fully penetrated into the small cracks and pores of the hole wall, forming a reinforced layer, the thickness of the reinforced layer is 3~8mm; during grouting, according to the actual situation and design requirements of the slurry hole, the grouting pressure is set in the range of 1-3MPa, for the slurry hole with more cracks in the hole wall and better permeability, the grouting pressure can be appropriately reduced; for the slurry hole with more dense hole wall and poor permeability, the grouting pressure can be appropriately increased, but not more than 3MPa, so as not to cause damage to the hole wall; start the grouting pump, slowly inject the prepared composite grouting material into the slurry hole; during grouting, the pressure gauge and flowmeter of the grouting pump are closely observed to ensure that the grouting pressure and flow are stable in the set range, and a person is arranged to observe the situation of the slurry hole, if it is found that the grouting material overflows from the hole, the grouting should be stopped immediately, the reasons are checked and corresponding measures are taken, such as adjusting the grouting pressure, checking the sealing device, etc.; in order to make the composite grouting material fully penetrate into the small cracks and pores of the hole wall, intermittent grouting method can be used. That is, after a period of grouting each time, the grouting is paused to allow the grouting material to fully diffuse and penetrate in the hole wall, and then the grouting is continued, the intermittent time can be determined according to the actual situation, generally 5~10min; during grouting, the thickness of the reinforced layer is controlled by controlling the grouting amount and grouting time, according to the diameter and length of the slurry hole, the grouting amount required to form a 3~8mm reinforced layer is calculated in advance, the grouting amount is monitored in real time during grouting, when the grouting amount approaches the theoretical calculation value, the grouting pressure is gradually reduced until the grouting is stopped; during grouting, the ultrasonic probe is placed near the slurry hole, the filling condition of the grouting material in the hole wall is measured by emitting and receiving ultrasonic signals, so as to determine the thickness of the reinforced layer. When the thickness of the reinforced layer reaches 3~8mm, the grouting is stopped.

[0010] S3, cement, fly ash, silica fume, water reducing agent, early strength agent and water are mixed and stirred in a certain proportion to prepare a cementing slurry, wherein the mass fraction of cement is 40%~60%, the mass fraction of fly ash is 15%~25%, the mass fraction of silica fume is 5%~10%, the mass fraction of water reducing agent is 0.5%~1.5%, the mass fraction of early strength agent is 1%~3%, and the balance is water.

[0011] S4, injecting the prepared cementing slurry into the slurry conveying hole which has been reinforced and treated for anti-seepage by the grouting pump, and monitoring the grouting pressure and the grouting amount in real time during the grouting process; when the grouting pressure reaches 5-8 MPa and the grouting amount reaches 95%-100% of the theoretical calculation value, the grouting is stopped; during the grouting, the grouting pressure is preliminarily set in the range of 5-8 MPa according to the actual situation and the design requirement of the slurry conveying hole; for the slurry conveying hole with relatively dense hole wall and poor permeability, the grouting pressure can be appropriately increased; for the slurry conveying hole with more cracks in the hole wall and good permeability, the grouting pressure can be appropriately reduced, but should not be lower than 5 MPa; the theoretical grouting amount is calculated according to the diameter, length and porosity of the slurry conveying hole, and is used as a reference basis for the control of the grouting amount; during the grouting process, the pressure gauge and the flowmeter of the grouting pump are closely observed, and the grouting pressure and the grouting amount are monitored and recorded in real time; at the same time, the filling situation of the cementing slurry in the slurry conveying hole is monitored in real time by using the ultrasonic monitoring technology; the ultrasonic monitoring equipment displays the filling height and the filling uniformity of the slurry and other information; the operator judges whether the grouting is uniform, whether there are cavities or unfilled areas according to the monitoring results; if the grouting pressure is too high or too low, the grouting amount is abnormal, the ultrasonic monitoring shows that the filling is not uniform, and the like, the grouting parameters should be adjusted in time; when the grouting pressure reaches 5-8 MPa and the grouting amount reaches 95%-100% of the theoretical calculation value, it is preliminarily judged that the grouting is basically completed, but the grouting should not be stopped immediately, and a comprehensive judgment should be made in combination with the ultrasonic monitoring results; if the ultrasonic monitoring shows that the cementing slurry is filled uniformly in the slurry conveying hole, and there is no obvious cavity or unfilled area, the grouting can be stopped; if the filling is not uniform, the grouting should be continued or other remedial measures should be taken until the requirement is met S5, after the cementing slurry injection is completed, the slurry conveying hole is maintained by using a segmented heating maintenance method; the segmented heating maintenance combined with natural maintenance can provide suitable curing conditions for the cementing material according to the environmental characteristics of the slurry conveying hole at different depths, guarantee the cementing effect, and when the segmented maintenance is performed, according to the actual situation of the slurry conveying hole, a suitable heating device is selected, if the diameter of the slurry conveying hole is small and the space is limited, an electric heating belt is more suitable, if the diameter of the slurry conveying hole is large and a large amount of heat is required, a steam heating pipe can be more suitable, the selected heating device is uniformly arranged along the axial direction of the slurry conveying hole, for the electric heating belt, the electric heating belt can be fixed on the inner wall of the slurry conveying hole in a winding or attaching manner, for the steam heating pipe, a support can be used to fix the steam heating pipe at a suitable position, the maintenance is segmented as follows: 0-2m range maintenance: in this range, the heating temperature is controlled at 30-40℃, the temperature in this range is monitored in real time through a temperature sensor, if the temperature is too high, the power of the heating device or the heating time can be appropriately reduced, if the temperature is too low, the power or the heating time can be increased, the maintenance time is 12-24h, during this period, a person is arranged to check the temperature and the operation of the heating device at regular time and make a record, 2-5m range maintenance: the heating temperature in this range is controlled at 20-30℃, the maintenance time is 24-36h, similarly, the temperature is monitored and controlled through the temperature sensor, since the distance from the hole to this range is far, the heat transfer is relatively slow, the arrangement density or the power of the heating device can be appropriately adjusted to ensure that the temperature is uniform, during the maintenance process, the temperature change trend is observed and the heating strategy is adjusted in a timely manner, the range below 5m is maintained by using a natural maintenance method, the maintenance time is not less than 7 days, during the natural maintenance period, the environment around the slurry conveying hole is kept relatively stable, a protection device is arranged at the slurry conveying hole to prevent sundries from entering the hole.

[0012] Further, in step S1, the nozzle diameter of the high-pressure water jet device is 2-5mm, the distance between the nozzle and the hole wall of the slurry conveying hole is 50-100mm, and during the flushing, the nozzle moves along the axial direction of the slurry conveying hole at a speed of 0.5-1m / min, and rotates around the nozzle axis at a speed of 30-60r / min. Further, in step S1, the pressure of the high-pressure water jet is dynamically adjusted according to the hardness of the rock layer where the slurry conveying hole is located, for a relatively hard rock layer, the pressure range is set to 20-30MPa, and for a relatively soft rock layer, the pressure range is set to 10-20MPa.

[0013] Further, in step S2, a defoaming agent with a mass fraction of 0.1%-0.5% is further added to the composite grouting material.

[0014] Further, in the step S3, a double-shaft forced stirrer is used for stirring in the preparation of the cementing slurry, the stirring speed is 60-80 r / min, the stirring time is 3-5 min, after the stirring is completed, the cementing slurry is left for 1-2 min, so that the bubbles in the slurry are naturally floated and overflowed, and then the grouting operation is performed.

[0015] Further, in the step S4, an ultrasonic monitoring technology is used for monitoring the filling condition of the cementing slurry in the grouting hole in real time during the cementing slurry injection, and the grouting parameters are adjusted in time according to the monitoring result.

[0016] Further, in the step S5, the electric heating belt or the steam heating pipe is used as the heating equipment, and the electric heating belt or the steam heating pipe is uniformly arranged along the axial direction of the grouting hole.

[0017] Further, after the cementing material curing is completed, the cementing quality is detected, the ultrasonic detector is used for detecting the thickness and uniformity of the cementing layer, the pressure testing machine is used for detecting the compressive strength of the cementing layer, and if the detection result does not meet the design requirement, the secondary grouting reinforcement treatment is performed.

[0018] Further, after the composite grouting material injection is completed, the sealing device is arranged at the grouting hole.

[0019] By adopting the technical scheme, the following beneficial effects can be brought about: The coal mine roadway grouting hole cementing process provided by the application significantly improves the cementing quality and stability of the coal mine roadway grouting hole through fine operation of multiple links, the high-pressure water jet device is used for dynamic adjustment of pressure for omnibearing flushing and roughening treatment according to the hardness of the rock stratum in the pretreatment stage, the impurities on the hole wall are effectively removed, the bonding area of the hole wall and the subsequent cementing material is increased, and a good foundation is laid for the cementing quality. The composite grouting material containing nano-silica sol and acrylate emulsion is injected, so that the composite grouting material fully penetrates into the tiny cracks and pores of the hole wall to form a reinforced layer, and the strength and anti-seepage performance of the hole wall are further enhanced. The accurate preparation and injection of the subsequent cementing slurry and the application of the segmented heating curing method ensure that the cementing material can fully hydrate and harden to form a stable cementing structure. Such omnibearing quality guarantee measures greatly reduce the probability of problems such as leakage and loosening after cementing, improve the long-term stability of the coal mine roadway grouting hole, and ensure the safety and efficiency of coal mine production.

[0020] The coal mine roadway slurry conveying hole well cementing process improves construction efficiency and realizes reasonable utilization of resources, during high-pressure water jet flushing, by reasonably setting the nozzle diameter, distance from the hole wall and moving and rotating speed, the omnidirectional uniform flushing of the hole wall is ensured, the subsequent well cementing quality problems caused by incomplete flushing are avoided, unnecessary flushing time and water resource waste are also reduced, during well cementing slurry preparation, a double-shaft forced mixer is used and the stirring speed and time are accurately controlled, so that the slurry has good fluidity and uniformity, construction delay caused by slurry quality problems is reduced, and the sectional heating curing method uses different heating temperatures and times according to different depths, which ensures the curing effect and avoids excessive energy consumption.

[0021] The coal mine roadway slurry conveying hole well cementing process, in the preparation process of the composite grouting material and the well cementing slurry, by adjusting the proportion of each component according to the geological conditions of the coal mine roadway and the well cementing requirements, the best performance of the well cementing material is obtained, so as to adapt to the characteristics of different rock layers, in the well cementing slurry injection process, the filling condition is monitored in real time by using ultrasonic monitoring technology, and the grouting parameters are adjusted in time according to the monitoring result, the accuracy and adaptability of the grouting process are ensured, after well cementing is completed, the well cementing quality is detected by using an ultrasonic detector and a pressure testing machine, if it does not meet the design requirements, secondary grouting reinforcement treatment can be carried out in time, the maintainability of the process is enhanced, the safety risk is reduced, various complex situations can be better coped with, the smooth progress of the coal mine roadway slurry conveying hole well cementing engineering is ensured, and the process has the advantages of strong adaptability and high stability. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the embodiments will be briefly introduced as follows, obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor.

[0023] Figure 1 A flowchart of the coal mine roadway slurry conveying hole well cementing process is provided. DETAILED DESCRIPTION

[0024] The embodiments of the present application will be described in detail below with reference to the drawings.

[0025] Following embodiments of the present application will be described in detail by way of specific examples. Other advantages and effects of the present application will be easily understood by those skilled in the art from the description of the present application. It is apparent that the described embodiments are only a part of embodiments of the present application, but not all embodiments of the present application. The present application can be implemented or applied in other different specific embodiments, and each detail in the description can be modified or changed based on different views and applications without departing from the spirit of the present application. It is noted that the following embodiments and features in the embodiments can be combined with each other without conflict. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of the present application.

[0026] It is noted that various aspects of the embodiments within the scope of the appended claims are described below. It should be apparent that the aspects described herein can be implemented in a wide variety of forms and that any particular structure and / or function described herein is merely illustrative. As an example, an apparatus and / or method can be implemented using any number of the aspects set forth herein. In addition, an apparatus and / or method can be implemented using other structures and / or functionalities in addition to or other than one or more of the aspects set forth herein.

[0027] It is also noted that the illustrative drawings included in the following embodiments are only schematic and so as not to limit the present application in its scope. In the drawings, like numbers indicate similar parts throughout the several views. It will be apparent to those having ordinary skill in the art that numerous changes can be made in the details of the illustrated embodiments and still be within the scope of the present application. It will be apparent that certain features of the embodiments described herein can be interchanged and / or modified without departing from the scope of the present application.

[0028] In addition, in the following description, specific details are provided to thoroughly understand the examples. However, it will be understood by those skilled in the art that the described aspects can be practiced without these specific details. Embodiment One

[0029] A coal mine roadway slurry hole well cementing process, comprising the following steps: S1, select the slurry hole in the coal mine roadway to be cemented, adjust the nozzle diameter of the high-pressure water jet device to 3mm, set the distance between the nozzle and the slurry hole wall to 70mm, use the hardness detector to detect the hardness of the rock layer where the slurry hole is located, and determine that it is a hard rock layer. Set the pressure of the high-pressure water jet device to 25MPa, turn on the high-pressure water jet device, and make the nozzle move along the axis of the slurry hole at a speed of 0.7m / min, while rotating around its own axis at a speed of 45r / min, to flush the slurry hole in all directions. During the flushing process, the high-pressure water flow washes away the rock debris and coal residue on the hole wall, and performs a preliminary roughening treatment on the hole wall, increasing the bonding area between the hole wall and the subsequent cementing material. After the flushing is completed, the high-pressure water jet device is turned off; S2, prepare a composite grouting material containing nano-silica sol, defoaming agent and acrylic ester emulsion. According to the mass fraction, take 7% of nano-silica sol, 5% of acrylic ester emulsion, 0.3% of defoaming agent, and the rest is water, and mix them evenly through a stirring device; inject the composite grouting material into the pretreated slurry hole, and control the grouting pressure at 2MPa. During the grouting process, the composite grouting material penetrates into the micro cracks and pores of the hole wall under the action of pressure, forming a reinforced layer with a thickness of about 5mm; after the injection of the composite grouting material is completed, a sealing device is installed at the slurry hole to prevent the overflow of the grouting material and maintain the stability of the grouting pressure, ensuring the full solidification of the composite grouting material; S3, take cement, fly ash, silica fume, water reducing agent, early strength agent and water according to a certain proportion. Among them, the mass fraction of cement is 50%, the mass fraction of fly ash is 20%, the mass fraction of silica fume is 7%, the mass fraction of water reducing agent is 1%, the mass fraction of early strength agent is 2%, and the rest is water; pour the weighed raw materials into a double-shaft forced mixer, set the stirring speed to 70r / min, and stir for 4min. During the stirring process, the raw materials are fully mixed and evenly distributed, forming a cementing slurry with good fluidity; after the stirring is completed, the cementing slurry is left to stand for 1.5min, so that the bubbles in the slurry can naturally float up and escape, reducing the bubble content in the cementing slurry and improving the cementing quality; S4, inject the prepared cementing slurry into the slurry hole treated by hole wall reinforcement and anti-seepage through a grouting pump, and monitor the grouting pressure and grouting volume in real time during the grouting process; at the same time, use ultrasonic monitoring technology to monitor the filling situation of the cementing slurry in the slurry hole in real time. When the grouting pressure reaches 6.5MPa and the grouting volume reaches 98% of the theoretical calculation value, according to the ultrasonic detection result, it is confirmed that the slurry hole is filled and the grouting is stopped; S5, after the cementing slurry injection is completed, a segmented heating curing method is used. In the range of 0-2m from the slurry delivery hole, an electric heating belt is used as the heating equipment, which is uniformly arranged along the axis direction of the slurry delivery hole, and the heating temperature is controlled at 35℃, and the curing time is 18h; in the range of 2-5m from the slurry delivery hole, an electric heating belt is also used, and the heating temperature is controlled at 25℃, and the curing time is 30h; in the range below 5m from the slurry delivery hole, a natural curing method is used, and the curing time is 8 days; after the curing is completed, an ultrasonic detector is used to detect the thickness and uniformity of the cementing layer, and a pressure testing machine is used to detect the compressive strength of the cementing layer. Through detection, the thickness of the cementing layer is uniform, and the compressive strength meets the design requirements. Example two

[0030] A coal mine roadway slurry delivery hole cementing process, comprising the following steps: S1, select the slurry delivery hole of the area to be cemented, adjust the nozzle diameter of the high-pressure water jet device to 2mm, and set the distance between the nozzle and the slurry delivery hole wall to 50mm; through detection, the rock layer where the slurry delivery hole is located is a relatively soft rock layer, and the pressure of the high-pressure water jet device is set to 15MPa; turn on the high-pressure water jet device, and make the nozzle move along the axis direction of the slurry delivery hole at a speed of 0.5m / min, while rotating around the nozzle axis at a speed of 30r / min, to flush and roughen the slurry delivery hole. After flushing, turn off the high-pressure water jet device; S2, prepare the composite grouting material, the mass fraction of nano-silica sol is 5%, the mass fraction of acrylic ester emulsion is 3%, the mass fraction of defoaming agent is 0.1%, and the balance is water; inject the composite grouting material into the slurry delivery hole, and control the grouting pressure at 1MPa. The composite grouting material penetrates to form a reinforced layer with a thickness of about 3mm; after injection, a sealing device is arranged at the slurry delivery hole; S3, weigh the raw materials, the mass fraction of cement is 40%, the mass fraction of fly ash is 25%, the mass fraction of silica fume is 10%, the mass fraction of water reducing agent is 1.5%, the mass fraction of early strength agent is 3%, and the balance is water; pour the raw materials into a double-shaft forced mixer, set the stirring speed to 60r / min, and stir for 5min. After stirring, stand for 1min to allow the bubbles to escape; S4, inject the cementing slurry through the grouting pump, and monitor the grouting pressure and grouting amount in real time. Use ultrasonic monitoring technology to monitor the filling condition. When the grouting pressure reaches 5MPa and the grouting amount reaches 95% of the theoretical calculation value, stop grouting; S5, use segmented heating curing. In the range of 0-2m from the slurry delivery hole, use a steam heating tube to heat, and control the temperature at 30℃ for 12h; in the range of 2-5m from the slurry delivery hole, control the heating temperature at 20℃ for 24h; the range below 5m is naturally cured for 7 days. After curing, the cementing quality meets the design requirements. Example three

[0031] A coal mine roadway slurry hole well cementing process, comprising the following steps: S1, select the slurry hole, adjust the nozzle diameter of the high-pressure water jet device to 5mm, set the nozzle distance from the hole wall to 100mm. Detect the rock layer as a hard rock layer, set the pressure to 30MPa, turn on the device, the nozzle moves at a speed of 1m / min, rotates at a speed of 60r / min, and turns off after flushing is completed; S2, prepare a composite grouting material, 10% nano silica sol, 8% acrylate emulsion, 0.5% defoaming agent, and the balance is water, stir uniformly, the grouting pressure is 3MPa, and a reinforcement layer with a thickness of about 8mm is formed. Set the sealing device after injection is completed; S3, weigh the raw materials, cement 60%, fly ash 15%, silica fume 5%, water reducing agent 0.5%, early strength agent 1%, and the balance is water, stirring speed 80r / min, time 3min, after stirring is completed, stand for 2min; S4, sectional heating and curing, the range of 0-2m of the hole, the electric heating belt is heated to 40℃, and cured for 24h; the range of 2-5m is heated to 30℃, and cured for 36h; below 5m is naturally cured for 9 days. After curing, the well cementing quality meets the design requirements.

[0032] The detection method of example 1, example 2 and example 3 mainly adopts the method of partition sampling inspection, 3 detection sections are taken every 100m of roadway, each section performs 1 direct detection (core taking / pressure water) + 1 indirect detection (acoustic wave / deformation detection), wherein the fracture filling rate obtained by core taking detection is all above 85%, the water permeability obtained by pressure water detection is all below 0.5, the longitudinal wave velocity improvement rate of the rock mass in the acoustic wave detection result is all above 20%, the separation amount in the deformation detection result is all less than 50mm / 100m, and the deformation rate decreases by more than 50%, so that the grouting hole after curing of example 1, example 2 and example 3 meets the design requirement of well cementing quality, in summary, the well cementing quality and stability of the coal mine roadway slurry hole are significantly improved, and the method has the advantages of high construction efficiency, full use of resources, strong adaptability and convenient maintenance.

[0033] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, any skilled person in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A coal mine roadway slurry hole well cementation process, characterized in that, The method comprises the following steps: S1, in the coal mine roadway well area, using high pressure water jet device for full range flushing of the slurry hole, removing the hole wall debris and coal slag, and at the same time, the hole wall is preliminarily roughened to increase the bonding area of the hole wall and the subsequent well cementing material; S2, in the pretreated slurry hole, a composite grouting material containing nano-silica sol and acrylic ester emulsion is injected by chemical grouting method, the mass fraction of nano-silica sol is 5%-10%, the mass fraction of acrylic ester emulsion is 3%-8%, and the grouting pressure is controlled at 1-3MPa, so that the composite grouting material fully penetrates into the micro cracks and pores of the hole wall to form a reinforced layer, and the thickness of the reinforced layer is 3-8mm; S3, cement, fly ash, silica fume, water reducing agent, early strength agent and water are mixed and stirred in a certain proportion to prepare well cementing slurry, wherein the mass fraction of cement is 40%-60%, the mass fraction of fly ash is 15%-25%, the mass fraction of silica fume is 5%-10%, the mass fraction of water reducing agent is 0.5%-1.5%, the mass fraction of early strength agent is 1%-3%, and the rest is water; S4, the prepared well cementing slurry is injected into the slurry hole which has been reinforced and anti-seepage treated by a grouting pump, and the grouting pressure and the grouting amount are monitored in real time during the grouting process, and when the grouting pressure reaches 5-8MPa and the grouting amount reaches 95%-100% of the theoretical calculation value, the grouting is stopped; S5, after the well cementing slurry injection is completed, the slurry hole is cured by a segmented heating curing method.

2. The coal mine roadway slurry hole well cementation process of claim 1, wherein: The nozzle diameter of the high pressure water jet device in the step S1 is 2-5mm, the distance between the nozzle and the hole wall of the slurry hole is 50-100mm, and during the flushing, the nozzle moves along the axis direction of the slurry hole at a speed of 0.5-1m / min, and rotates around the nozzle axis at a speed of 30-60r / min.

3. A coal mine roadway slurry hole well cementation process according to claim 2, characterized in that: During the flushing process of the step S1, the pressure of the high pressure water jet is dynamically adjusted according to the hardness of the rock stratum where the slurry hole is located, for the relatively hard rock stratum, the pressure range is set to 20-30MPa, and for the relatively soft rock stratum, the pressure range is set to 10-20MPa.

4. The coal mine roadway slurry hole well cementation process of claim 3, characterized in that: The step S2 further adds a defoaming agent with a mass fraction of 0.1%-0.5% in the composite grouting material.

5. A coal mine tunnel slurry hole cementing process according to claim 4, characterized in that: During the preparation of the well cementing slurry in the step S3, a double-shaft forced stirrer is used for stirring, the stirring speed is 60-80r / min, and the stirring time is 3-5min, after the stirring is completed, the well cementing slurry is left for 1-2min to make the air bubbles in the slurry float up and escape naturally, and then the grouting operation is performed.

6. A coal mine roadway slurry hole well cementation process according to claim 5, characterized in that: During the well cementing slurry injection process of the step S4, an ultrasonic monitoring technology is used to monitor the filling condition of the well cementing slurry in the slurry hole in real time, and the grouting parameters are adjusted in time according to the monitoring result.

7. A coal mine roadway slurry hole well cementation process according to claim 6, characterized in that: In the step S5, the segmented heating curing method is used in the range of 0-2m from the slurry hole, the heating temperature is controlled at 30-40℃, and the curing time is 12-24h; in the range of 2-5m from the slurry hole, the heating temperature is controlled at 20-30℃, and the curing time is 24-36h; in the range below 5m from the slurry hole, a natural curing method is used, and the curing time is not less than 7 days.

8. A coal mine roadway slurry hole well cementation process according to claim 7, characterized in that, The segmented heating curing method in the step S5 adopts an electric heating belt or a steam heating pipe as a heating device, and the electric heating belt or the steam heating pipe is uniformly arranged along the axis direction of the slurry conveying hole.

9. A coal mine roadway slurry hole well cementation process according to claim 8, characterized in that: After the curing of the well cementing material is completed, the well cementing quality is detected, the thickness and uniformity of the well cementing layer are detected by using an ultrasonic detector, the compressive strength of the well cementing layer is detected by using a pressure testing machine, and if the detection result does not meet the design requirement, secondary grouting reinforcement treatment is performed.

10. A coal mine roadway slurry hole well cementation process according to claim 9, characterized in that, After the injection of the composite grouting material is completed, a sealing device is arranged at the slurry conveying hole.

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