Artificial stratum bare hole freezing technology

Abstract

The invention discloses an artificial stratum bare hole freezing process method which comprises the following steps: S1, mixing basic slurry with a low-temperature additive, a stabilizer and an anti-freezing agent according to a certain proportion to prepare an ultralow-temperature drilling fluid; s2, freezing holes, temperature measuring holes and hydrological holes are formed, and temperature measuring pipes and hydrological pipes are put down and installed; s3, after freezing hole forming is completed, a refrigerating system is used for cooling the drilling fluid, and circulating operation of the ultralow-temperature drilling fluid in the hole is started; and S4, after the frozen curtain is formed, the ultralow-temperature drilling fluid continues to be circulated, and it is ensured that the temperature of the frozen curtain is And S5, excavation and supporting construction of underground engineering are conducted, and construction safety is guaranteed. And S6, after engineering construction is completed, circulating work of the ultralow-temperature drilling fluid is stopped, and the freezing curtain is gradually unfrozen. And S7, filling the freezing holes and treating waste liquid. According to the method, the working efficiency is improved, the construction safety is enhanced, and the method is environmentally friendly and has remarkable economic benefits and social benefits.

Description

Technical Field

[0001] The present invention relates to the technical field of mine roadway construction, and specifically refers to an artificial ground bare hole freezing technology process. Background Technique

[0002] During the development of deep and western coal mineral resources in China, artificial freezing method is often used for the excavation of vertical shafts in thick soil layers, thick pore (fracture)-rich water-bearing rock layers or strata with both. The definition of the freezing method (i.e., artificial ground freezing technology) is: First, drill holes in the water-bearing soil layer, insert freezing steel pipes into the drill holes, and then use artificial refrigeration technology to circulate low-temperature refrigerant in the freezing pipes, so that the water in the stratum freezes, turning natural rock and soil into frozen soil, increasing its strength and stability, isolating the connection between groundwater and underground projects, so as to carry out the special construction technology of shaft or underground project excavation and lining construction under the protection of the freezing wall. The freezing method is a geotechnical reinforcement technology originated from natural freezing phenomena and is one of the important means to ensure the stability and safety of underground projects.

[0003] Traditional freezing methods mainly rely on the lowering of steel freezing pipes, and the freezing and reinforcement of the stratum are realized by circulating cooling media to provide necessary support and prevent groundwater seepage. However, this traditional method has several significant technical defects: First, due to the influence of ground pressure and temperature stress, the steel freezing pipes may break in complex geological conditions, increasing the construction risk and possibly causing project delays; Second, the annular space formed around the freezing pipes often becomes a potential water conduction channel, resulting in water flow-through phenomena and affecting the overall sealing performance of the freezing curtain; Third, the extensive use of steel not only increases the cost but also causes resource waste. Especially when the freezing pipes need to be pulled out later, not only are the freezing pipes difficult to pull out, but also the additional process complexity and time cost are increased. In view of the above problems, the present invention proposes an artificial ground bare hole freezing process method using ultra-low temperature drilling fluid instead of steel freezing pipes, aiming to overcome the defects of the existing technology, improve construction safety and efficiency, reduce resource waste and enhance the freezing effect. Summary of the Invention

[0004] I. Technical Problems to be Solved

[0005] The technical problem to be solved by the present invention is various problems mentioned in the above background technique, and an artificial ground bare hole freezing technology process is provided.

[0006] II. Technical Solutions

[0007] To solve the above technical problems, the technical solution provided by the present invention is: An artificial ground bare hole freezing process method, including the following steps:

[0008] S1: Mix the base mud with cryogenic additives, stabilizers, and antifreeze agents in a certain proportion and stir evenly to prepare an ultra-low-temperature drilling fluid.

[0009] S2: Carry out the hole drilling work for freezing holes, temperature measurement holes, and hydrogeological holes, and lower and install temperature measurement pipes and hydrogeological pipes.

[0010] S3: After the freezing hole drilling is completed, adjust the freezing station equipment, cool the drilling fluid using the refrigeration system, and start the circulation operation of the ultra-low-temperature drilling fluid in the hole; promptly adjust the performance of the drilling fluid in the return liquid treatment tank; during freezing, promptly measure the temperature of the temperature measurement hole and observe the hydrogeological hole to evaluate the freezing intersection situation.

[0011] S4: After the freezing curtain is formed, continue to circulate the ultra-low-temperature drilling fluid to ensure the strength and thickness of the freezing curtain.

[0012] S5: Carry out the excavation and support construction of the underground project. During the construction process, closely monitor the deformation and temperature changes of the freezing curtain to ensure construction safety.

[0013] S6: After the project construction is completed, gradually stop the circulation work of the ultra-low-temperature drilling fluid, and the freezing curtain gradually thaws.

[0014] S7: Fill the freezing holes and treat the waste liquid.

[0015] As an improvement, in step S1, the base mud contains fresh water and 1 - 3% sodium-based bentonite, the cryogenic additive contains 0.1 - 0.3% xanthan gum, the stabilizer contains 1 - 3% filtration reducer; the antifreeze agent contains 25 - 45% ultra-low-temperature base liquid and 1 - 3% lubricant.

[0016] As an improvement, before hole drilling in step S2, it is necessary to clean the construction area to ensure that the drilling rig operation platform is flat and stable, meeting the bearing capacity requirements. At the same time, install equipment such as the drilling rig, drilling fluid circulation system, and inclinometer, connect the water and electricity supply, then determine the hole type as a vertical hole, and gradually rotate downward with the help of the drilling fluid's wall protection performance in cooperation with a rotary drilling rig, impact drill, etc., and carry out the waste slag in the hole under the circulation supply of the drilling fluid.

[0017] As an improvement, in step S5, according to the project needs, bury temperature, strain, or earth pressure sensor gauges in the underground project support structure and the freezing curtain to monitor the temperature, deformation, or stress of the support structure and the freezing curtain.

[0018] As an improvement, in step S7, the freezing holes are filled and the waste liquid is treated. The specific operations include pulling out the liquid supply pipe of the drilling fluid, lowering a high-pressure-resistant grouting hose to the bottom of the freezing hole, injecting a cement-based or other type of filling material through the grouting hose, lifting the grouting pipe while injecting the slurry, filling with a cement-based or other type of material within a range of not less than 20 m from the upper part, or injecting a cement-based or other type of filling material through the liquid supply pipe. For the waste liquid, solid-liquid separation is first carried out, then chemical treatment, and finally, after membrane filtration, it meets the sewage discharge standard.

[0019] III. Beneficial effects

[0020] The advantages of the present invention compared with the prior art are as follows:

[0021] 1. The artificial formation open-hole freezing process method provided by the present invention precisely formulates cryogenic drilling fluid and uses the cryogenic drilling fluid to replace the steel freezing pipe, eliminating the risk of freezing pipe fracture caused by the action of ground pressure and temperature stress, and greatly improving the safety and reliability of the construction process. During the freezing process, it does not rely on the freezing pipe, but realizes formation freezing through the circulation of cryogenic drilling fluid, effectively avoiding the annular space formed around the traditional freezing pipe from becoming a potential water-conducting channel, preventing the occurrence of water flow channeling phenomenon, and avoiding the water inrush accident in the freezing pipe annular space during the excavation of the chamber adjacent to the shaft.

[0022] 2. The artificial formation open-hole freezing process method provided by the present invention no longer requires lowering and deeply burying the freezing pipe. The present invention reduces the use of a large amount of steel, reduces costs and saves resources at the same time. In addition, this also simplifies the complex processes such as pulling out the freezing pipe that may be involved in the later construction, improving the overall construction efficiency. This provides a more solid and reliable guarantee for underground engineering construction, ensures construction safety, and helps to improve the project quality. Overall, the present invention improves work efficiency, enhances construction safety, and is environmentally friendly, with significant economic and social benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a schematic diagram of the artificial formation open-hole freezing technology process of the present invention.

[0024] Figure 2 is a process flow chart of the artificial formation open-hole freezing technology of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0025] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0026] As Figure 1 shown in Figure 2 Figure [not provided], an artificial formation open-hole freezing process method includes the following steps:

[0027] S1: Mix basic mud with cryogenic additives, stabilizers, and antifreeze agents in a certain proportion and stir evenly to prepare ultra-low temperature drilling fluid.

[0028] S2: Carry out the hole-making work for freezing holes, temperature-measuring holes, and hydrogeological holes, and lower and install temperature-measuring tubes and hydrogeological tubes.

[0029] S3: After the hole-making of the freezing holes is completed, adjust the freezing station equipment, cool the drilling fluid using the refrigeration system, and start the circulation operation of the ultra-low temperature drilling fluid in the holes; timely adjust the performance of the drilling fluid in the return fluid treatment tank; during the freezing period, timely measure the temperature of the temperature-measuring holes and observe the hydrogeological holes to evaluate the freezing intersection situation.

[0030] S4: After the freezing curtain is formed, continue to circulate the ultra-low temperature drilling fluid to ensure that the freezing curtain does not heat up.

[0031] S5: Carry out the excavation and support construction of the underground project. During the construction process, it is necessary to closely monitor the deformation and temperature changes of the freezing curtain to ensure construction safety.

[0032] S6: After the project construction is completed, gradually stop the circulation work of the ultra-low temperature drilling fluid, and the freezing curtain gradually thaws.

[0033] S7: Fill the freezing holes and treat the waste liquid.

[0034] The specific implementation of the present invention is as follows:

[0035] A certain coal mine is located in the western region of China. The shaft diameter is large, the alluvium is shallow, the soft bedrock is deep, and there are many aquifers. The bedrock is mostly Cretaceous and Jurassic rock formations, with poor cementation, low strength, and water softening when encountering water; most of the aquifers are pore-fissure aquifers, with a large thickness of the aquifers, and the poorly sealed freezing holes and the gaps behind the shaft lining become important hidden water-conducting channels.

[0036] First, mix and stir evenly the base mud (including clear water and 1-3% sodium-based bentonite), low-temperature additive (0.1-0.3% xanthan gum), stabilizer (1-3% filtration reducer), and antifreeze (25-45% ultra-low temperature base fluid and 1-3% lubricant) in a specific proportion to prepare an ultra-low temperature drilling fluid with specific specific gravity, funnel viscosity, and water loss (step S1). Next, on the basis of cleaning and ensuring the construction area is flat and stable, install equipment such as a drilling rig, drilling fluid circulation system, and inclinometer, and connect the water and electricity supply. Then, use tools such as a rotary drilling rig or percussion drill to drill freezing holes, temperature measuring holes, and hydrogeological holes, and lower and install temperature measuring tubes and hydrogeological tubes at the corresponding positions (step S2). After the freezing holes are completed, adjust the freezing station equipment, cool the drilling fluid through the refrigeration system, and start the circulation operation of the ultra-low temperature drilling fluid in the freezing holes. At the same time, adjust the performance of the drilling fluid in the return fluid treatment tank to maintain its optimal state. During this period, regularly monitor the freezing situation through the temperature measuring holes and hydrogeological holes (step S3). When the freezing curtain is formed, continue to maintain the circulation of the ultra-low temperature drilling fluid to prevent the temperature of the freezing curtain from rising (step S4). Subsequently, during the excavation and support construction stage of the underground project, through the temperature, strain gauges, and earth pressure gauge sensors buried in the support structure and the freezing curtain, monitor the temperature and force changes in real time to ensure construction safety (step S5). After the project construction is completed, gradually stop the circulation of the ultra-low temperature drilling fluid to gradually thaw the freezing curtain (step S6). Finally, carry out the filling of the freezing holes and the treatment of waste liquid: pull out the supply pipe, use a high-pressure resistant grouting hose to the bottom of the freezing hole, lift the grouting pipe while grouting, and fill with cement-based materials within a range not less than 20m from the top; for the generated waste liquid, carry out solid-liquid separation, chemical treatment, and membrane filtration in sequence until the sewage discharge standard is reached (step S7). This method effectively avoids the problems that may occur in traditional freezing technologies and improves the construction efficiency and safety.

[0037] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variation thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device.

[0038] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

[0039] The above describes the present invention and its implementation manners. Such description is not restrictive. What is shown in the drawings is only one of the implementation manners of the present invention, and the actual structure is not limited thereto. All in all, if those of ordinary skill in the art are inspired by it and, without departing from the gist of the present invention, design similar structural manners and embodiments to this technical solution without creative efforts, they shall fall within the protection scope of the present invention.

Claims

1. A method for freezing an artificial stratum bare hole, characterized in that: The following steps are involved: S1: Mix the base mud with the low-temperature additive, stabilizer and antifreeze agent in a certain proportion, stir evenly, and prepare the ultra-low-temperature drilling fluid; S2: Carry out the drilling work of freezing holes, temperature measuring holes and hydrological holes, and install the temperature measuring pipes and hydrological pipes; S3: After the freezing hole is drilled, adjust the freezing station equipment, use the refrigeration system to cool the drilling fluid, and start the circulation of ultra-low temperature drilling fluid in the hole; timely adjust the performance of the drilling fluid in the return liquid treatment pool; measure the temperature of the temperature measuring hole and observe the hydrological hole in time during the freezing period to evaluate the freezing circle situation; S4: After the freezing curtain is formed, continue to circulate the ultra-low temperature drilling fluid to ensure the strength and thickness of the freezing curtain; S5: Carry out excavation and support construction of underground projects. During the construction process, the deformation and temperature changes of the freezing curtain must be closely monitored to ensure construction safety; S6: After the construction is completed, the circulation of ultra-low temperature drilling fluid is gradually stopped, and the frozen curtain gradually thaws; S7: Filling of freezing holes and waste liquid treatment.

2. The method for freezing an artificial stratum bare hole according to claim 1, characterized in that: In step S1, the base mud comprises clean water and 1-3% sodium bentonite, the low-temperature additive comprises 0.1-0.3% xanthan gum, the stabilizer comprises 1-3% fluid loss reducer, and the antifreeze comprises 25-45% ultra-low temperature base fluid and 1-3% lubricant.

3. The method for freezing an artificial stratum bare hole according to claim 1, characterized in that: In step S2, the construction area needs to be cleaned before drilling, ensuring that the drilling rig working platform is flat and stable and meets the bearing capacity requirements. At the same time, the drilling rig, drilling fluid circulation system, inclinometer and other equipment are installed, and the water and electricity supply are connected. Then, the type of hole to be drilled is determined to be a vertical hole. The wall protection performance of the drilling fluid is used to cooperate with the rotary drilling rig, impact drill, etc. to gradually rotate downward, and the waste residue in the hole is taken out under the circulation supply of the drilling fluid.

4. The method for freezing an artificial stratum bare hole according to claim 1, characterized in that: In step S5, according to the engineering requirements, temperature, strain gauges or earth pressure gauge sensors are embedded in the underground engineering support structure and the freezing curtain to monitor the temperature, deformation or stress of the support structure and the freezing curtain.

5. The method for freezing an artificial stratum bare hole according to claim 1, characterized in that: The step S7 fills the freezing hole and treats the waste liquid. The specific operation includes pulling out the drilling fluid supply pipe, inserting a high-pressure grouting hose until the bottom of the freezing hole, pressing cement-based or other types of filling materials through the grouting hose, lifting the grouting pipe while grouting, and filling with cement-based or other types of materials within a range of not less than 20m above. Cement-based or other types of filling materials can also be pressed into the liquid supply pipe. The waste liquid is first separated into solid and liquid, then chemically treated, and finally filtered through a membrane to meet the sewage discharge standard.

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