Intelligent construction method for reinforcing gas melting type frozen soil foundation

Abstract

According to the intelligent construction method for reinforcing the gas-melting type frozen soil foundation, a bidirectional stirring pile machine is adopted for drilling downwards, a drill rod of the pile machine is an inner-outer double-layer drill rod, the bottom end of the inner drill rod extends out of an outer drill rod and is provided with a spray hole, a suction channel is formed between the outer drill rod and the inner drill rod, and a suction hole is formed in the bottom end of the outer drill rod; in the drilling process, saturated steam is intermittently sprayed into a drill hole through the spraying holes, stirring is carried out while spraying is carried out, ice water formed after melting is sucked through the suction holes, and back flushing is carried out on the suction holes through high-pressure gas in the period; high-pressure gas is sprayed into the drill hole during drill lifting, the suction hole is kept to suck ice water during lifting, and the high-pressure gas is adopted for backflushing. During drilling, melting of ice water in the frozen soil can be accelerated by spraying saturated steam to the frozen soil, and the temperature of the saturated steam is inversely proportional to the drilling speed, that is, the lower the drilling speed is, it shows that the current frozen soil is difficult to melt, so that the temperature of the saturated steam is increased, and the melting speed of the frozen soil is greatly increased compared with a traditional method.

Description

Technical Field

[0001] The invention relates to the technical field of frozen soil foundation treatment, and in particular to an intelligent construction method for reinforcing a gas-thaw frozen soil foundation. Background Art

[0002] Seasonal frozen soil in my country is mainly distributed in North China, Northwest China and Northeast China. As the latitude and bottom height increase, the winter temperature is getting lower and lower, and the thickness of seasonal frozen soil is getting larger and larger. The harm of seasonal frozen soil to buildings is manifested in two aspects: frost heave and thaw settlement. There are two reasons for the frost heave of the soil layer. When the water freezes into ice, the volume increases by 9%. When the soil layer freezes, the water in the surrounding unfrozen area will gather in the surface frozen area, which increases the water content in the soil layer in the frozen area. The frozen ice crystals continue to grow larger, and the soil body also expands and bulges accordingly.

[0003] The frost heave of frozen soil can cause the roadbed to bulge, the flexible road surface to bulge and crack, and the rigid road surface to misalign or break; frost heave can also lift up the buildings built on it, causing them to crack, tilt, or even collapse.

[0004] Freeze-thaw can also cause houses, bridges, and culverts to sink in large quantities or sink unevenly, causing cracks and damage to buildings. Therefore, the frost heave and freeze-thaw of seasonal frozen soil will bring harm to the project, which must be paid attention to and necessary protective measures must be taken.

[0005] There are two common methods for dealing with frozen soil: (1) Maintaining the frozen ground: This is a design method that always keeps the ground in a frozen state. Generally speaking, when the thickness of frozen soil is large and the soil temperature is relatively stable, or when the frozen soil is hard and has a high thawing collapse rate, it is more reasonable to adopt the maintaining the frozen ground method. This is especially true for the foundation of power transmission lines. If measures can be taken to ensure that the temperature of the frozen soil around the foundation is not higher than the natural state, the design can be carried out according to the maintaining the frozen ground method.

[0006] A design that remains frozen should be used in one of the following situations: a) Permafrost ground with an annual average ground temperature below -1°C; b) The foundation soil within the bearing layer is in a hard frozen state; c) Within the range of maximum melting depth, there are foundations with melting settlement, severe melting settlement, melting-collapse soil and their interlayers.

[0007] The following methods are usually used: 1. Pile foundation method; 2. Cushion method; 3. Ventilation foundation method; 4. Heat pipe foundation method; 5. Artificial freezing method.

[0008] (2) Allowing for thawing: Using the land that is thawing or has just thawed as the foundation, the soil layer with high bearing capacity of thawing is shallower; it is more reasonable to adopt the principle of allowing thawing for small pieces of discontinuously distributed island-shaped frozen soil with small thawing amount. In particular, the design of structures with good upper structure stiffness or insensitive to uneven settlement should be based on the principle of allowing thawing. When the estimated thawing amount exceeds the allowable deformation value of the foundation, the artificial pre-thawing method can also be used to melt the frozen soil and then build the foundation. Or the foundation can be appropriately reinforced (such as replacing soil with low melting property, etc.) When designing according to the principle of allowing thawing, the strength of the hydrochloric acid foundation (including the bearing layer and the underlying layer) should be calculated. When determining the bearing capacity value of the foundation, the physical and mechanical property indicators used should try to simulate the actual stress state of the foundation in the future. In addition to strength verification, the deformation of the foundation must also be calculated. The calculation method and allowable deformation value of the foundation deformation are the same as those of the general natural foundation. Only the compressibility index needs to be replaced with the deformation property index of the thawing soil or the thawed soil so that the thawing deformation can be taken into account.

[0009] Through a large number of engineering practices, it was found that the traditional methods did not remove the moisture in the frozen soil, diseases still existed, and the construction cost was high. Summary of the invention

[0010] The technical problem to be solved by the present invention is that the conventional method does not remove the moisture in the frozen soil and has a high cost. An intelligent construction method for gas-thaw frozen soil foundation reinforcement is proposed to solve the above problem.

[0011] The technical problem to be solved by the present invention is achieved through the following technical solutions: an intelligent construction method for gas-thawing frozen soil foundation reinforcement, which adopts a two-way mixing pile driver for drilling. The drill rod of the pile driver is an inner and outer double-layer drill rod. The bottom end of the inner drill rod extends out of the outer drill rod and is provided with a spray hole. A suction channel is formed between the outer drill rod and the inner drill rod, and a suction hole is provided at the bottom end of the outer drill rod. When drilling, saturated steam is intermittently sprayed into the borehole from the spray hole. The saturated steam temperature is inversely proportional to the drilling speed. The steam is stirred while spraying, and the ice water formed after melting is sucked through the suction hole. During this period, the suction hole is recoiled by high-pressure gas. When lifting the drill, high-pressure gas is sprayed into the borehole from the spray hole. The steam is stirred while spraying. During this period, the suction hole is kept sucking ice water, and high-pressure gas is used for recoil.

[0012] Preferably, during drilling, the time interval of intermittent saturated steam injection is 3-5s, the saturated steam temperature is 140-170°C, and the saturated steam injection pressure is 0.4-0.8Mpa.

[0013] Preferably, during the drilling process, the time interval for intermittent spraying of high-pressure gas is 2-4s, and the spraying pressure of high-pressure gas is 0.4-0.7Mpa.

[0014] Preferably, the ice water pumping and the backwashing are performed alternately, and the interval between the alternations is 40-60s.

[0015] Preferably, the drilling speed is 0.2-0.5 m / min.

[0016] Preferably, when drilling, when the current value of the motor of the bidirectional pile mixing machine used to drive the drill rod to drill is greater than 35A, the drilling speed of the drill rod is reduced.

[0017] Preferably, stirring blades are provided at the bottom of the inner drill rod and the outer drill rod, and an electric heating plate is installed on the stirring blade of the inner drill rod, and the temperature of the electric heating plate is controlled at 300-500°C.

[0018] Preferably, melted ice water is used to prepare saturated steam.

[0019] Preferably, it also includes a saturated steam system and a recovery system; The saturated steam system includes a gas storage tank, a high-temperature water vapor tank, an air compressor and a water pump. The air compressor is connected to the gas storage tank through a pipeline. The gas storage tank is connected to the bottom of the high-temperature water vapor tank through a pipeline. The water pump is connected to the high-temperature water vapor tank. A heater is arranged in the high-temperature water vapor tank. A high-pressure and high-temperature gas delivery pipe is arranged on the top of the high-temperature water vapor tank. A high-pressure gas delivery pipe is arranged on the gas storage tank, and the high-pressure gas delivery pipe is connected to the high-pressure and high-temperature gas delivery pipe. The recovery system includes a water storage tank, a vacuum pump and a vacuum delivery pipe. The end of the vacuum delivery pipe is connected to the water storage tank through the vacuum pump, the bottom of the water storage tank is connected to the water pump through a pipeline, and a backflush pipe is provided between the vacuum delivery pipe and the gas storage tank. A feed port and a discharge port are arranged on the drill rod of the bidirectional mixing pile machine, a high-pressure gas delivery pipe is connected to the feed port, and a vacuum delivery pipe is connected to the discharge port.

[0020] It also includes a saturated steam tank. One end of the high-pressure and high-temperature gas delivery pipe is connected to the drill rod feed port of the two-way mixing pile driver, and the other end is connected to the top of the saturated steam tank.

[0021] Pressure sensors and temperature sensors are installed on the high-temperature water vapor tank and the saturated steam tank.

[0022] A pneumatic valve I is arranged at the air inlet end of the vacuum pump, a pneumatic valve II is arranged on the pipeline between the vacuum pump and the water storage tank, a gas-water separator is arranged on the pipeline between the pneumatic valve II and the vacuum pump, a pneumatic valve III is arranged on the pipeline between the water storage tank and the water pump, an external water source pipeline is arranged on the pipeline between the pneumatic valve III and the water pump, a pneumatic valve IV is arranged on the external water source pipeline, a pneumatic valve V is arranged on the pipeline between the high-temperature water vapor tank and the gas tank, a pneumatic valve VI is arranged on the end where the high-pressure and high-temperature gas delivery pipe is connected to the high-temperature water vapor tank, a pneumatic valve VII is arranged on the high-pressure gas delivery pipe, a pneumatic valve VIII is arranged on the pipeline between the water pump and the high-temperature water vapor tank, and a pneumatic valve IX is installed on the backblowing pipe.

[0023] The drill rod of the bidirectional mixing pile machine comprises the inner drill rod and the outer drill rod sleeved on the outer peripheral surface of the inner drill rod; The top of the inner drill rod is matched with the power head arranged on the top of the bidirectional mixing pile machine, and a feeding channel is reserved in the middle of the inner drill rod, one end of the feeding channel is connected to the feeding port, and the other end is arranged near the inner drill rod mixing blade and connected to the spray hole; The top end of the outer drill rod is connected to the power head arranged on the top of the bidirectional mixing pile driver through a reversing bevel gear transmission, so that the rotation direction of the outer drill rod is opposite to that of the inner drill rod. The space between the inner circumference of the inner drill rod and the outer circumference of the outer drill rod forms the suction channel, one end of the suction channel is connected to the discharge port, and the other end is arranged close to the mixing blade of the outer drill rod and is connected to the suction hole.

[0024] A filter screen is arranged at the suction hole of the outer drill rod.

[0025] An exhaust valve is provided on the top of the water storage tank.

[0026] The operation steps of intelligent reinforcement of air-thaw frozen soil foundation are as follows: All construction parameters are input into the program of the intelligent control cabinet. The input control parameters are as follows: (1) Set the drilling speed, which is generally 0.2-0.4 / min, according to the degree of dissolution of frozen soil. When drilling, if the current value is too large, the transmission system will automatically reduce the drilling speed. The judged current value is generally not more than 35A; (2) Setting the design depth of the drilling; (3) Set the temperature of the PTC electric heating plate; (4) Set the pulse interval and the interval between vacuuming and blowing; (5) Set the verticality deviation value required by the design; Construction technology: 1. Clean the site and level it to the designed elevation; 2. Lofting: Based on the axis and edge of the construction area, use a steel ruler to stake out the pile positions point by point; 3. Positioning: Move the pile driver, align the drill bit with the pile position, collect the displayed data through the verticality sensor (accuracy: 0.005°), and adjust the verticality; 4. Click the start button of the intelligent control cabinet: the background and the host are ready according to the set procedures, and the production of high-pressure and high-temperature water vapor and the heating of the electric heating drill bit PTC heating plate are completed; 5. Open the inner and outer drill rods to rotate in both the forward and reverse directions, start the transmission system, and the electrically heated drill bit starts drilling; 6. When the electric heating drill bit enters the soil, open the pneumatic valve VI and work according to the set pulse interval time; 7. Drill according to the set drilling speed. When the current value is large, the drilling speed is automatically adjusted to ensure that the vibration rod sinks at a uniform speed; 8. Turn on the vacuum pump to extract the water or water vapor produced by the melting of frozen soil; 9. Pneumatic valve I and pneumatic valve IX are opened and closed alternately at set intervals to keep the water suction port of the outer drill pipe unobstructed; 10. After reaching the designed depth, the transmission system reverses and starts lifting; 11. Close pneumatic valve VI and open pneumatic valve VII to change the high-pressure and high-temperature water vapor injected into the frozen soil into high-pressure gas for pulse operation; 12. Until the electric heating drill bit is lifted out of the ground, the intelligent reinforcement construction of the gas-thawing frozen soil foundation is completed.

[0027] Compared with the prior art, the beneficial technical effects of the present invention are: (1) When drilling with a bidirectional mixing pile driver, the melting of ice water in the frozen soil can be accelerated by spraying saturated steam into the frozen soil. The saturated steam temperature is inversely proportional to the drilling speed. That is, the slower the drilling speed, the more difficult it is to melt the frozen soil. By increasing the temperature of the saturated steam, the melting speed of the frozen soil is greatly increased compared with the traditional method. The melted ice water is extracted through the suction hole to remove the moisture in the frozen soil, fundamentally changing the frozen soil structure and avoiding bulging and cracking of the road surface due to frost heave after subsequent roadbed construction. (2) Back-blowing measures are added to the process. When the soil particles after the frozen soil melts are adsorbed into the suction holes during the suction process, compressed air is blown back to the suction holes to avoid blockage of the suction holes. (3) When lifting the drill, high-pressure gas is used to supply air to the borehole to facilitate the removal of water from the melted frozen soil during suction through the suction hole; (4) An electric heating plate is installed on the stirring blade of the inner drill rod. The electric heating plate can directly heat the stirring blade that is stirring the frozen soil, thereby improving the melting efficiency of the frozen soil. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a construction schematic diagram of the present invention; Figure 2 It is a schematic diagram of the structure of the pile driver, saturated steam system and recovery system of the present invention; Figure 3 It is a schematic diagram of the structure of the saturated steam system and the recovery system of the present invention; Figure 4 The inner drill rod and the outer drill rod of the pile driver of the present invention; Figure 5 It is a schematic diagram of the pneumatic dynamic soil foundation reinforcement monitoring and management system of the present invention.

[0029] In the figure, 1. bidirectional mixing pile driver; 2. inner drill rod; 3. outer drill rod; 4. spray hole; 5. suction hole; 6. pneumatic valve IX; 7. mixing blade; 8. electric heating plate; 9. gas storage tank; 10. high-temperature water vapor tank; 11. air compressor; 12. water pump; 13. heater; 14. high-pressure and high-temperature gas delivery pipe; 15. high-pressure gas delivery pipe; 16. water storage tank; 17. vacuum pump; 18. vacuum delivery pipe; 19. backflush pipe; 20. exhaust valve; 21. feed inlet; 22. discharge outlet; 23. power head; 24. pneumatic valve I; 25. pneumatic valve II; 26. gas-water separator; 27. pneumatic valve III; 28. external water source pipeline; 29. ​​pneumatic valve IV; 30. pneumatic valve V; 31. pneumatic valve VI; 32. pneumatic valve VII; 33. pneumatic valve VIII. DETAILED DESCRIPTION

[0030] The specific technical solutions of the present invention are further described below with reference to the accompanying drawings, so as to facilitate further understanding of the present invention by those skilled in the art, and do not constitute a limitation on the rights thereof.

[0031] Example 1, reference Figure 1 , an intelligent construction method for reinforcing frozen soil foundation with air thawing type, using a two-way mixing pile driver 1 for drilling, the drill rod of the pile driver is an inner and outer double-layer drill rod, the bottom end of the inner drill rod 2 extends out of the outer drill rod 3 and is provided with a spray hole 4, a suction channel is formed between the outer drill rod 3 and the inner drill rod 2, and a suction hole 5 is provided at the bottom end of the outer drill rod 3, the number of suction holes 5 can be set to multiple, a filter is provided at the suction hole 5 of the outer drill rod 3, the mesh size of the filter is determined according to the diameter of the soil particles to prevent the soil particles from being sucked out, when the soil particles are adsorbed on the filter, high-pressure air is used for pulse back filtering to flush out the soil particles adsorbed on the filter, that is, backwashing operation; When drilling, saturated steam is sprayed intermittently into the borehole from the spray hole 4. The time interval of the intermittent spraying of saturated steam is 3-5s. The saturated steam temperature is 140-170°C. The saturated steam spraying pressure is 0.4-0.8Mpa. The saturated steam temperature is inversely proportional to the drilling speed. The drilling speed is 0.2-0.5m / min. Stirring is performed while spraying. The ice water formed after melting is sucked through the suction hole 5. During this period, the suction hole 5 is recoiled by high-pressure gas. In addition, when drilling, the degree of dissolution of frozen soil reflects the magnitude of the current value during drilling. The drilling speed is automatically controlled according to the magnitude of the current value. That is, when the motor current value of the two-way mixing pile machine 1 used to drive the drill rod to drill is greater than 35A, the drilling speed of the drill rod is reduced until the motor current value returns to the normal current value. The drilling speed can be restored. The normal current value is 35A. When the drill is lifted, high-pressure gas is sprayed into the borehole from the spray hole 4. The time interval of intermittent spraying of high-pressure gas is 2-4s, and the spraying pressure of high-pressure gas is 0.4-0.7Mpa. Stirring is performed while spraying. During this period, the suction hole 5 is kept to suck ice water, and high-pressure gas is used for recoil. When drilling down and lifting the drill, ice water suction and backwash are performed alternately, with an interval of 40-60 seconds; Stirring blades 7 are provided on the outer peripheral surfaces of the bottoms of the inner drill rod 2 and the outer drill rod 3. An electric heating plate 8 is installed on the stirring blades 7 of the inner drill rod 2. The temperature of the electric heating plate 8 is controlled at 300-500°C. Specifically, it can be a PTC, that is, a positive temperature coefficient thermistor, for heating. The number of installed electric heating plates can be selected according to usage requirements. In addition, the temperature of the electric heating plate can be automatically adjusted according to the freezing degree of the frozen soil. For example, when the drilling speed is reduced, the temperature of the electric heating plate 8 can be increased. The specific temperature value can be adjusted according to usage requirements.

[0032] Example 2, reference Figure 2-5 , the intelligent construction method for gas-thaw frozen soil foundation reinforcement described in Example 1 further includes a saturated steam system and a recovery system; The saturated steam system includes a gas storage tank 9, a high-temperature water vapor tank 10, an air compressor 11 and a water pump 12. The air compressor 11 is connected to the gas storage tank 9 through a pipeline. The gas storage tank 9 is connected to the bottom of the high-temperature water vapor tank 10 through a pipeline. The water pump 12 is connected to the high-temperature water vapor tank 10. A heater 13 is provided in the high-temperature water vapor tank 10. A high-pressure and high-temperature gas delivery pipe 14 is provided on the top of the high-temperature water vapor tank 10. A high-pressure gas delivery pipe 15 is provided on the gas storage tank 9, and the high-pressure gas delivery pipe 15 is connected to the high-pressure and high-temperature gas delivery pipe 14. The recovery system includes a water storage tank 16, a vacuum pump 17 and a vacuum delivery pipe 18. The end of the vacuum delivery pipe 18 is connected to the water storage tank 16 through the vacuum pump 17. The bottom of the water storage tank 16 is connected to the water pump 12 through a pipeline. A backflush pipe 19 is provided between the vacuum delivery pipe 18 and the air storage tank 9. An exhaust valve 20 is provided at the top of the water storage tank 16. A feed port 21 and a discharge port 22 are provided on the drill rod of the bidirectional mixing pile driver 1 . The high-pressure gas delivery pipe 15 is connected to the feed port 21 , and the vacuum delivery pipe 18 is connected to the discharge port 22 .

[0033] Embodiment 3, the intelligent construction method for gas-thawing frozen soil foundation reinforcement described in Embodiment 2 also includes a saturated steam tank, one end of the high-pressure and high-temperature gas transmission pipe 14 is connected to the drill rod feed port 21 of the bidirectional mixing pile driver 1, and the other end is connected to the top of the saturated steam tank.

[0034] Embodiment 4, an intelligent construction method for reinforcing frozen soil foundation by gas-thawing method described in Embodiment 3 or 2, wherein a pressure sensor and a temperature sensor are installed on the high-temperature water vapor tank 10 and the saturated steam tank.

[0035] Embodiment 5, an intelligent construction method for strengthening frozen soil foundation with air thawing type as described in Embodiment 4, wherein a pneumatic valve I 24 is provided at the air inlet end of the vacuum pump 17, a pneumatic valve II 25 is provided on the pipeline between the vacuum pump 17 and the water storage tank 16, an air-water separator 26 is provided on the pipeline between the pneumatic valve II 25 and the vacuum pump 17, a pneumatic valve III 27 is provided on the pipeline between the water storage tank 16 and the water pump 12, and an external A water source pipeline 28 is provided, and a pneumatic valve IV 29 is provided on the external water source pipeline 28, a pneumatic valve V 30 is provided on the pipeline between the high-temperature water vapor tank 10 and the gas storage tank 9, a pneumatic valve VI 31 is provided on the end where the high-pressure and high-temperature gas delivery pipe 14 is connected to the high-temperature water vapor tank 10, a pneumatic valve VII 32 is provided on the high-pressure gas delivery pipe 15, a pneumatic valve VIII 33 is provided on the pipeline between the water pump 12 and the high-temperature water vapor tank 10, and a pneumatic valve IX 6 is installed on the backblowing pipe 19.

[0036] Embodiment 6, an intelligent construction method for reinforcing frozen soil foundation with air thawing type as described in Embodiment 4, the drill rod of the bidirectional mixing pile driver 1 comprises the inner drill rod 2 and the outer drill rod 3 sleeved on the outer peripheral surface of the inner drill rod 2; The top end of the inner drill rod 2 is in transmission cooperation with the power head 23 arranged on the top of the bidirectional mixing pile machine 1. A feeding channel is reserved in the middle of the inner drill rod 2. One end of the feeding channel is connected to the feeding port 21, and the other end is arranged near the inner drill rod mixing blade 7 and is connected to the spray hole 4. The top end of the outer drill rod 3 is connected to the power head 23 arranged on the top of the bidirectional mixing pile driver 1 through a reversing bevel gear transmission, so that the rotation direction of the outer drill rod 3 is opposite to that of the inner drill rod 2, and the dissolved frozen soil is stirred in two directions, so that the soil particles are rearranged and combined, and the heated surface area is increased, thereby improving the dissolution rate of the frozen soil; the space between the inner circumference of the inner drill rod 2 and the outer circumference of the outer drill rod 3 forms the suction channel, one end of the suction channel is connected to the discharge port 22, and the other end is arranged near the outer drill rod stirring blade 7 and is connected to the suction hole 5.

[0037] The melted ice water participates in the preparation of saturated steam.

[0038] 1. The working principle is as follows: Click the start button of the intelligent control cabinet, the pneumatic valve IV29 and the pneumatic valve VIII33 are opened, the water pump 12 is turned on to inlet water, when the water in the high-temperature water tank reaches the set weight value, the water pump 12 is automatically closed, and the pneumatic valve IV29 and the pneumatic valve VIII33 are closed (when the weight of the water is lower than the set value of 30kg, the water pump 12 automatically replenishes water), and the heater 13 in the high-temperature water tank, that is, the electric heater, starts to work. When the water temperature reaches the set value (measured by the temperature sensor), the electric heater 13 stops working (when the water temperature is lower than the set value of 2°C, the electric heater 13 automatically starts to maintain the set value of the water temperature); the air compressor 11 starts automatically, and when the pressure value of the air storage tank 9 reaches the set value, the air compressor 11 stops working (when the air pressure is lower than the set value of 0.1Mpa, the air compressor 11 automatically starts to maintain the set value of the air pressure); the pneumatic valve V30 is opened, and the high-pressure air enters the high-temperature water tank, and passes through The high-temperature water is heated to form high-pressure and high-temperature water vapor; the PTC (positive temperature coefficient thermistor) electric heating plate on the electric heating drill bit starts to start (according to the data of different frozen soil layers in the geological survey data, the temperature of the PTC electric heating plate is set at 300-500 degrees by the thermostat in the intelligent control cabinet). When the PTC electric heating plate reaches the set temperature, the inner drill rod 2 is started first, and then the outer drill rod 3 is started, and the forward and reverse directions are rotated. The transmission system is started, and the electric heating drill bit starts to drill. When it enters the soil, the pneumatic valve VI 31 opens, and the high-pressure and high-temperature water vapor enters the inner drill rod 2 through the high-pressure and high-temperature gas transmission pipe 14 and is sprayed out from the spray hole 4 on the inner drill rod 2. At this time, the frozen soil begins to dissolve under the combined action of the high temperature of the PTC electric heating plate and the high-pressure and high-temperature water vapor. The degree of dissolution can be reflected by the current value when drilling. According to the degree of dissolution of the frozen soil, the drilling speed is generally controlled at 0.2-0.4m / min. When the current value is too large during the drilling process, the transmission system automatically reduces the drilling speed to meet the melting of frozen soil. The high-pressure and high-temperature water vapor is ejected in a pulse mode. The interval time is generally controlled at 3-5 seconds according to the melting degree of frozen soil. At this time, the vacuum pump 17 is started, and the pneumatic valve I 24 is opened to suck the water and water vapor generated by the melting of frozen soil into the gas-water separator through the suction hole 5 set on the outer drill rod 3, the channel between the inner and outer drill rods 3, the water and gas pumping device, and the vacuum conveying pipe 18. The pneumatic valve II 2 5 is opened, the gas-water separator separates the gas, and the sucked water enters the water storage tank 16; when the soil particles after the frozen soil melts are adsorbed to the suction hole 5 on the outer drill rod 3 during the vacuuming process, the pneumatic valve I 24 is closed, and the pneumatic valve IX 6 is opened, and the high-pressure air blows off the soil particles adsorbed in the suction hole 5 on the outer drill rod 3. The vacuuming and blowing work alternately. According to the adsorption of soil particles, the alternating working time is generally set between 40 and 60 seconds; when the drilling reaches the designed depth, the transmission system reverses and starts to lift, and the pneumatic valve VI 31 is closed, and pneumatic valve VII 32 is opened. At this time, only high-pressure gas is sprayed out through the spray hole 4 of the inner drill rod 2. The purpose is to reduce the water content in the frozen soil (high-pressure and high-temperature water gas is sprayed when drilling down. At this time, the high-pressure gas contains a certain amount of water, which is conducive to dissolving the frozen soil. When the frozen soil is dissolved, it is not suitable to spray water). At this time, the high-pressure gas sprayed in also adopts pulse operation. The general interval time is set to 2-4 seconds, which is shorter than the pulse interval time when drilling down. A part of the gas volume is increased to facilitate the removal of water in the dissolved frozen soil when vacuuming. During the construction process, the weight sensors installed on the high-temperature water tank and the water storage tank 16 are used to measure the water injected and the water sucked out. The difference in volume is compared with the geological survey data to determine the reinforcement effect of the frozen soil. When the amount of water stored in the water storage tank 16 reaches the set upper limit, the pneumatic valve IV 29 is closed, the pneumatic valve III 27 is opened, and the water pump 12 transports the water in the water storage tank 16 to the high-temperature water tank, which plays an environmental protection and energy-saving role (frozen soil is generally distributed in high-altitude areas, where water resources are relatively scarce).

[0039] 2. Monitoring and management system (refer to Figure 5 ): The equipment consists of the following parts: on-site inspection, on-site monitoring management, and monitoring center; (1) When Internet terminal devices such as mobile phones, tablets, PCs, platform monitoring centers, and on-site inspection equipment obtain data, they dispatch the server to the application server, and the application server reads the data directly from the cache database, which can greatly reduce the reading pressure of the database server and return data results more quickly.

[0040] (2) Since the module transmits data once every 1-3 seconds, the number of data is large and the data volume is huge; we write the collected real-time data into files and store them in the attachment server. If conditions permit, multiple attachment servers can be clustered; the files stored in the attachment server contain the piling process data of all pile drivers, so in the application system, this stored data can be called to simulate the dynamic process of the original operation.

[0041] (3) The data page display platform integrates a camera video monitoring system, and the video stream data is broadcast live online to display the construction site conditions in real time. At the same time, after the data transmitted from the Internet of Things module is collected, the websocket technology is integrated to synchronize it to each terminal device in real time, dynamically displaying the progress of the construction work.

[0042] (4) The on-site monitoring management and monitoring center automatically generates original on-site construction records and statistical tables based on the received on-site construction parameters, eliminating human factors, ensuring the authenticity of the data, and significantly reducing labor costs.

[0043] (5) For completed loose soil reinforcement foundations, if there are any disputes after testing, the construction process can be replayed to find out the problem.

[0044] (6) In case of irregular operation or special circumstances on site, instructions can be sent to the control cabinet of the intelligent reinforcement mixing pile machine for gas-thawing frozen soil foundation to terminate the on-site construction and reduce losses.

Claims

1. An intelligent construction method for reinforcing frozen soil foundation with air thawing, characterized in that: A two-way mixing pile driver is used for drilling. The drill rod of the pile driver is an inner and outer double-layer drill rod. The bottom end of the inner drill rod extends out of the outer drill rod and is provided with a spray hole. A suction channel is formed between the outer drill rod and the inner drill rod, and a suction hole is provided at the bottom end of the outer drill rod. When drilling, saturated steam is sprayed intermittently from the spray hole into the borehole. The temperature of the saturated steam is inversely proportional to the drilling speed. The steam is stirred while spraying, and the ice water formed after melting is sucked through the suction hole. During this period, the suction hole is recoiled by high-pressure gas. When lifting the drill, high-pressure gas is sprayed into the borehole from the spray hole, stirring while spraying. During this period, the suction hole is kept to suck ice water, and high-pressure gas is used for recoil.

2. According to claim 1, the intelligent construction method for strengthening the frozen soil foundation by air thawing is characterized by: During drilling, the time interval of intermittent saturated steam injection is 3-5s, the saturated steam temperature is 140-170℃, and the saturated steam injection pressure is 0.4-0.8Mpa.

3. The intelligent construction method for reinforcing frozen soil foundation by gas-thawing method according to claim 1 is characterized in that: During the drilling process, the time interval for intermittent injection of high-pressure gas is 2-4s, and the injection pressure of high-pressure gas is 0.4-0.7Mpa.

4. The intelligent construction method for reinforcing frozen soil foundation with air thawing method according to claim 1 is characterized in that: Pumping ice water and backwashing are performed alternately, with an interval of 40-60s.

5. The intelligent construction method for reinforcing frozen soil foundation by gas-thawing method according to claim 1 is characterized in that: The drilling speed is 0.2-0.5m / min.

6. The intelligent construction method for reinforcing frozen soil foundation with air thawing method according to claim 1 is characterized by: When drilling, if the motor current value of the two-way mixing pile machine used to drive the drill rod to drill is greater than 35A, the drilling speed of the drill rod will be reduced.

7. An intelligent construction method for reinforcing frozen soil foundation by gas-thawing method according to any one of claims 1 to 6, characterized in that: Stirring blades are arranged on the outer peripheral surfaces of the bottoms of the inner drill rod and the outer drill rod. An electric heating plate is installed on the stirring blade of the inner drill rod. The temperature of the electric heating plate is controlled at 300-500℃.

8. An intelligent construction method for reinforcing frozen soil foundation by gas-thawing method according to any one of claims 1 to 6, characterized in that: The melted ice water participates in the preparation of saturated steam.

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