CN112144559A - Construction method of piezo-transformer tube well in high water-rich loess sandy pebble formation - Google Patents

Abstract

The invention provides a method for constructing a well in a transformer tube well in a high water-rich loess sand pebble stratum, comprising the following steps: excavating a counterbore, making a caisson in the counterbore, and reserving two side walls on both sides of the caisson to pass through the main pipeline. Opening of the hole; push the pipe sections of the two main pipes from the opening of the caisson respectively; measure and position; check the construction of the wellbore at the bottom of the well; check the backfill around the wellbore at the bottom of the well; After the top of the bed, the subgrade in the caisson is backfilled and constructed together with the base of the overall road; slurry preparation and grouting reinforcement; auger rotary drilling rig is used to form holes; cement: water glass: water in a mass ratio of 1:0.1: 1. The ratio is double-liquid slurry. Before use, the double-liquid slurry is evenly mixed and filtered through a screen. The advantages of this method are that the construction period of inspection wells and pipelines is shortened, the disturbance of jacking is reduced, and the direct impact on the buildings on the ground is avoided, which provides a guarantee for the advance penetration of the road, and at the same time, the overall quality of the project is greatly improved.

Description

Construction method of piezo-transformer tube well in high water-rich loess sandy pebble formation

technical field

The invention relates to a construction method for a pressure-transformer tube well in a high-water-rich loess sand and pebble stratum.

Background technique

A "well in a well" refers to an inspection well that is secondary fabricated in a caisson. The traditional municipal road "well in the well" construction is to build sintered bricks or pour reinforced concrete wells in the caisson, and complete the backfill around the well. However, in the high-water-rich loess-sand-cobble area of the pressure transformer pipe (due to the long-term abnormal operation of the downstream sewage treatment plant, the head pressure changes in the pipe), the inspection well is made in the deep well (>10m) caisson. Due to the poor sealing performance of the two materials in the inspection well and the irregular change in the water head difference in the pipe, the joints between the wellbore, the pipe body and the pipe mouth are prone to cracks due to impact. The deep sand outside the pipe is hollowed out and the loess subsides, resulting in uneven settlement of the pavement in the later stage.

Due to the characteristics of the regional soil layers, and the large diameter sewage and sewage pipes (1.5-3.0m) caisson structures are generally relatively large, they cannot be directly used as inspection wells. There is a lack of a well-in-the-tube construction method in the high-water-rich loess sand and pebble formation.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to provide a well construction method in a piezo-transformer tube well with reasonable technology and convenient construction.

In order to solve the above-mentioned technical problems, the present invention provides a construction method for a pressure-transformer tube well in a high-water-rich loess sandy pebble stratum, comprising the following steps:

a) caisson construction

Excavate a counterbore at a predetermined position, and the depth of the counterbore exceeds the predetermined depth of the main pipeline;

The reinforced concrete caisson is made on the four walls and bottom wall of the shaft at the lower part of the caisson according to the construction drawings. The caisson is sealed with no drainage. The caisson is made and sunk many times. The side walls of the caisson are reserved for the passage of the main pipeline. hole;

b) Pipe jacking construction

The pipe sections of the main pipeline are hoisted into the caisson in turn, and the pipe sections of the two main pipes are respectively pushed out from the opening of the caisson through the jacking equipment, and there is a gap between the pipe sections of the two main pipes;

c) Measuring and positioning

According to the center coordinates of the inspection well in the drawing, the coordinates of the four corners of the caisson are calculated through the structure size and arrangement of the caisson;

d) Check the wellbore construction at the bottom of the well

Step-by-step construction on site, the first step is to construct the well chamber floor, the second step to construct the well chamber wall, and the third step to construct the reinforced concrete wellbore;

Chisel the bottom of the caisson, then pour the bottom concrete of the inspection well, and pre-embed the steel reinforcement of the well wall when pouring the bottom concrete;

Before the construction of the inspection well wall, intercept the pipeline according to the distance between the caisson and the inspection well, connect the pipeline on both sides, and pour the foundation. Rebar of the shaft;

The wellbore is a square wellbore, and supports are erected from bottom to top to provide a working platform for operators. The pipeline crossing the well wall is filled with linseed tar sand, and the upstream surface is sealed with polysulfide sealant;

e) Check the backfill around the wellbore downhole

The backfill around the well is backfilled with the sand from the water-falling sand site. When the backfill surface no longer has fine air bubbles, the water injection can be stopped;

After the on-site water-falling sand is completed, sample the ring knife at the site in time, obtain the relevant data with the balance and microwave oven drying method, and measure the degree of compaction;

The external platform of the wellbore can backfill the surrounding soil of the well room to a certain height in advance. After backfilling to the elevation of the branch pipe, install the branch pipe, and protect the finished product when the branch pipe is backfilled;

f) Inspection of upper wellbore construction and backfilling

The upper shaft structure of the inspection well is brick masonry. After the reinforced concrete shaft is completed, it is backfilled to the top of the reinforced concrete shaft;

g) Construction of road subgrade and sub-base

Since the inspection well is within the subgrade range of the road, after the caisson is backfilled to the top of the road bed, the subgrade in the caisson is backfilled and constructed together with the base of the overall road;

h) Preparation of slurry and grouting reinforcement

The plane position of the drilling hole should be consistent with the plane position of the weak and weak parts inside and outside the caisson, and select multiple points to arrange grouting holes, and the distance between points should be ≤1.0m;

The auger rotary drilling machine is used to form the hole, the diameter of the hole is 70mm to 110mm, the allowable deviation of verticality is ±1%, and the hole depth is from the roadbed to the pipe jacking pipe or weak and weak parts;

Mix cement: water glass: water into a double-liquid slurry in a mass ratio of 1:0.1:1. Before use, the double-liquid slurry is evenly mixed and filtered through a screen;

The double grout is poured through the grouting pipe. Before pouring, the gap between the outside of the grouting pipe and the orifice should be closed with cement mortar. The medium and double slurries are continuously stirred slowly, the stirring time is less than the initial setting time, the flow rate of grouting is 5~10L/min, the water temperature is controlled between 0 ℃ ~ 30 ℃, and the initial setting time of the double slurries is 55min;

i) Maintenance and inspection acceptance

Closed traffic management is adopted for the area where grouting is completed, and the surrounding large-scale machinery and vibration machinery are prohibited for construction;

28 days after grouting is completed, the inspection is carried out, and the standard penetration method is used for inspection. The grouting inspection point is 3% of the number of grouting holes. When the pass rate is less than 80%, repeated grouting is performed.

As a preference of this method, the step d) inspects the construction of the lower wellbore, and the lower wellbore is about 3m high for one pouring, and the construction can be divided into sections greater than 3m.

As a preference of the method, in the step e), the construction of the upper wellbore of the inspection well is checked, and the inner and outer walls of the wellbore are plastered with 1:2 cement mortar plus 5% waterproofing agent to a thickness of 20 mm.

As a preference of this method, in the step h) preparation of the slurry and grouting reinforcement, the stirring time in the preparation of the slurry should be greater than 2 minutes, the water-cement ratio should be controlled at 0.8 to 1, and then the volume of the slurry mixing bucket should be adjusted to the mixing bucket. Add a certain amount of water glass solution and stir evenly, and control the volume ratio of water glass to cement slurry between 0.5 and 0.8.

As a preference of this method, in the step h) preparation of the slurry and grouting reinforcement, according to the area of the caisson, the grouting holes are arranged in a plum blossom shape, and the hole depth is from the roadbed to the pipe joint, and the auger is used for rotary drilling to form a hole. The diameter is 70mm～110mm, and the allowable deviation of verticality is ±1%.

As a preference of this method, the caisson cover is prefabricated, and the through hole at the top of the inspection well is reserved on the caisson cover. After h) the preparation of the slurry and the reinforcement by grouting, the caisson cover is covered on the upper side of the caisson.

As a preference of this method, in the step h), the grouting pipes are divided into several first grouting pipes and several second grouting pipes, and the several first grouting pipes are divided into two groups, and the two groups of first grouting pipes and The pipe sections on both sides correspond, and the lower ends of the first grouting pipes of each group extend to the upper side of the pipe sections on the inside and outside of the caisson; the lower ends of several second grouting pipes extend to the periphery of the connection between the upper wellbore and the lower wellbore of the inspection well.

After this method is adopted, the pipe jacking technology can be used to carry out pipeline laying without affecting the ground facilities, avoiding the direct impact of the operation on the buildings or structures on the ground. The possibility of land subsidence.

After ensuring the quality of the caisson and checking the quality of the caisson floor, start to tie the steel bars to the formwork according to the position of the pipeline, pour the lower concrete inspection well chamber, and complete the masonry of the upper well chamber when the lower well chamber is completed. The backfill material between the lower caisson and the inspection well is the original medium-coarse sand, and the layer (20cm) is backfilled by the water-falling sand insertion vibrating rod tamping method. To form a water flow circulation, the sand density must meet the requirements of compaction; between the upper caisson and the inspection well, 3:7 lime soil is used to evenly backfill around the well.

After the subgrade and sub-base are completed, the exit of the directional grouting pipe is placed at the junction of the brick masonry under construction and the concrete roof, the opening reserved for the caisson and the weak point of the pipeline through the auger excavation hole, the elevation and coordinate control. And the pipeline between the caisson and the inspection well, and through the pressure grouting, the double grout should be injected into the formation through the grouting pipe, and the strong solidified grout will be injected into the formation. The grout will fill, penetrate, compact and split In other ways, the water and air in the soil particles are squeezed out and occupy their positions. After the slurry is consolidated, the original loose soil particles or fissures are cemented into a whole, and inclusions are formed through infiltration, filling, and compaction expansion.

Since there are pores in the gravel layer and medium and coarse sand tools in the stratum, a certain amount of grout is injected into the soil layer through drilling, and the soil around the grouting port is squeezed and filled to form a plastic wrapping area, which is far away from the grout. The soil mass of the grouting mouth is elastically deformed, and the overall density of the soil mass around the grouting port is increased. This inclusion forms a combination with the compacted foundation soil, which together play the role of rapid reinforcement, filling voids and cracks, and sealing cracks caused by hydraulic shock.

Under the combined action of dense backfilling of some materials in the upper and lower wellbore parts and grouting reinforcement at the weak parts, the collapse of the road around the well caused by the "water hammer effect", the unbalanced water pressure inside and outside, and the load of the road surface caused by the weak parts are overcome. question.

The advantages of the construction method of the piezo-transformer tube well in the high-water-rich loess sand and pebble stratum are: shortening the construction period of inspection wells and pipelines, reducing the disturbance of jacking, avoiding the direct impact on the above-ground buildings, and reducing the ground to the greatest extent. Possibility of subsidence. It provides a guarantee for the road to pass through in advance, and at the same time, the overall quality of the project is greatly improved, which provides a lot of good reference for the implementation of similar projects in the country in the future, and produces significant social benefits.

Description of drawings

Fig. 1 is a schematic elevational view of an embodiment of the construction method for a piezo-transformer well in a high-water-rich loess sand and pebble formation of the present invention.

Fig. 2 is the process flow diagram of the embodiment of the construction method of the piezo-transformer well in the high-water-rich loess sand and pebble formation.

Detailed ways

As shown in Figures 1 to 2

Taking the construction of pipe jacking well in Fengxi New City as an example, here, the upper geology is high water-rich loess stratum, and the lower geology is sandy pebble stratum.

a) caisson construction

Excavate a counterbore at a predetermined position, and the depth of the counterbore exceeds the predetermined depth of the main pipeline;

The reinforced concrete caisson 2 is made on the four walls and bottom wall of the shaft at the lower part of the counterbore according to the construction drawing. The caisson 2 is sealed with undrained bottom. the opening through which the main pipeline passes;

Before the concrete is poured, the size of the formwork, the position of the embedded parts, and the tightness of the formwork shall be inspected.

b) Pipe jacking construction

The pipe sections 11 of the main pipeline are hoisted into the caisson 2 in turn, installed through the guide rails, the back wall is fabricated, the jacking equipment is installed, the pipe jacking machine head is in place, the machine head is inserted into the hole, and the pipe section 11 and the top iron are placed. For advancing and correcting deviation, the pipe sections 11 of the two main pipelines are respectively ejected from the opening of the caisson 2 through the jacking equipment. There is a certain distance between the pipe sections 11 of the two main pipelines. The main console observes the deviation of the pipe jacking when the pipe is jacked in, to prevent the head from swinging left and right, increase the disturbance to the sand and pebble layer, and form a larger cavity outside the pipe wall. When there is still 5m from the receiving well, the head is controlled to exit The speed of the hole and the central axis of the hole, slowly push the machine head into the receiving well, lift the pipe jacking head with a truck, and continue to jack the pipe to the predetermined position.

c) Measuring and positioning

According to the center coordinates of the inspection well in the drawings, the coordinates of the four corners of the caisson 2 are calculated through the structural size and arrangement of the caisson 2, and the ink fountain is used to set out the line, and the coordinate points are released on site and marked with wooden stakes.

d) Check the construction of the wellbore 33 in the lower part of the well

According to the structural form of the designed inspection well, the on-site construction is carried out step by step, the first step is to construct the well chamber bottom plate 34, the second step to construct the well chamber wall and roof, and the third step to construct the reinforced concrete wellbore;

After the pipe jacking is completed, the debris and silt in the caisson 2 are cleaned up, the bottom plate of the caisson 2 below the well chamber of the inspection well is chiseled, the bottom plate concrete of the inspection well is poured, and the well is pre-buried when pouring the concrete of the inspection well bottom plate 34. Wall reinforcement, if it is necessary to plant reinforcement for construction, do pullout test after planting reinforcement;

Before the construction of the inspection well wall, intercept the pipeline according to the distance between the caisson 2 and the inspection well, connect the pipeline on both sides, and pour the foundation. The material required for vertical transportation is hoisted, and the concrete is poured by pump truck, vibrated by vibrating rod, the chute concrete is poured together with the well wall, and the steel bars of the wellbore are pre-buried on the roof;

The lower wellbore 33 of the inspection well is a square wellbore of 1m*1m. The height of the lower wellbore 33 is about 3m at a time. Sections larger than 3m can be constructed. When constructing the wellbore of the inspection well, the main difficulty is that the installation space of the inner formwork is limited. In the wellbore, only one person can work. By pre-embedding steel bars at the opening of the well chamber and erecting brackets from bottom to top, a working platform for operators is provided. The water surface is sealed with polysulfide sealant.

e) 33 weeks of backfilling of wellbore downhole inspection

The backfill around the well shall be backfilled with sand from the water-falling sand site (that is, the backfill area 52 of the caisson), the soil shall be transported by trucks, and the backfill shall be manually leveled. The water injection is 20cm higher than the filling height, keep the water head, the water surface sinks slowly, and when the backfill surface no longer has fine air bubbles, the water injection can be stopped;

After the on-site water-falling sand is completed, sample the ring knife at the site in time, obtain the relevant data with the balance and microwave oven drying method, and measure the degree of compaction, specifically:

The outer wellbore 33 at the bottom of the well is backfilled with medium and coarse sand at the same time, and the thickness of each layer of backfill is not more than 20cm. The elevation is marked on the outer wall of the inspection well. The water injection is 20cm higher than the filling height, and the water head is maintained. When fine air bubbles emerge, water injection can be stopped. During the water injection process, the plug-in vibrating rod is used for tamping. The sand-free water filter pipe wrapped in geotextile is installed in the caisson to pump and drain water to form a water flow circulation. The sand density must meet the requirements of density. , in time to the on-site ring knife to sample, use the balance and microwave oven drying method to obtain relevant data, and measure the degree of compaction;

The external platform of the wellbore can backfill the surrounding soil of the well room to a certain height in advance. After backfilling to the elevation of the branch pipe 35, install the branch pipe 35, and protect the finished product when the branch pipe 35 is backfilled.

f) Inspection of the construction and backfilling of the wellbore 32 in the upper part of the well

The structure of the upper wellbore 32 of the inspection well is brick masonry. After the wellbore of the inspection well is completed, the inner and outer walls of the upper wellbore 32 of the inspection well are plastered with 1:2 cement mortar and 5% water repellent with a thickness of 20mm, and the top of the inspection well is provided with an upper cover 31;

The backfill around the brick inspection well is backfilled with 3:7 lime soil evenly around the well, and then compacted with a small tamper, backfilled in layers, compacted in layers, and the thickness of each layer of backfill is not more than 15cm.

g) Construction of road subgrade and sub-base

Then backfill around the upper wellbore of the inspection well (that is, the subgrade backfill area 51), because the inspection well is within the subgrade range of the road, after backfilling to the top surface of the road bed, the subgrade in the caisson 2 is backfilled and constructed together with the base of the overall road .

h) Preparation of slurry and grouting reinforcement

Considering that the double-liquid slurry has the characteristics of fast setting time, it is necessary to measure the initial and final setting time of the slurry on site to ensure that the time from the preparation to the use of the slurry does not exceed the initial setting time. Glass:water is prepared in a mass ratio of 1:0.1:1 to prepare a double slurry. A movable steel mixing bucket is set up on site to prepare the slurry. The bucket capacity is ≥800L. Before use, the double slurry is evenly mixed and filtered through a screen.

The plane position of the drilling hole should be consistent with the plane position of the weak and weak parts inside and outside the caisson 2, and select multiple points to arrange the grouting holes, and the distance between points should be ≤1.0m.

The auger rotary drilling machine is used to form the hole, the diameter of the hole is 70mm to 110mm, the allowable deviation of the verticality is ±1%, and the hole depth is from the roadbed to the pipe jacking pipe or weak and weak parts.

The double grout is poured through a grouting pipe with a diameter of 50mm. Before pouring, cement mortar should be used to close the gap between the outside of the grouting pipe and the orifice. After the closed mud solidifies, remove the active plug of the grouting pipe, and the injection pressure is 0.4Mpa , During the grouting process, the double slurries are continuously stirred slowly, and the stirring time is less than the initial setting time.

When the final hole requirements are met, the grouting hole is filled with gravel and gravel and supplemented with cement-sodium silicate slurry to form a micro pile body, and the orifice is restored with cold filling materials.

The grouting pipe is divided into a plurality of first grouting pipes 41 and a plurality of second grouting pipes 42 , and the plurality of first grouting pipes 41 are divided into two groups, two groups of first grouting pipes 41 and two side pipe sections 11 Correspondingly, the lower ends of the first grouting pipes 41 of each group extend to the upper side of the pipe sections 11 on the inner and outer sides of the caisson 2; the lower ends of the plurality of second grouting pipes 42 extend to the upper wellbore 32 of the inspection well and are connected to the lower wellbore 33 of the inspection well around the place.

The grouting hole is filled with crushed stone and gravel and supplemented with cement/water glass slurry to form micro-inclusions, and the orifice is restored by cold filling.

The caisson cover plate 21 is prefabricated, and the through hole at the top of the inspection well is reserved on the caisson cover plate 21 .

i) Maintenance and inspection acceptance

The closed traffic management is adopted for the area where the grouting is completed, and the surrounding large-scale machinery and vibration machinery are prohibited for construction.

28 days after the completion of grouting, the inspection shall be carried out, and the standard penetration method shall be selected for inspection; the grouting inspection point is 3% of the number of grouting holes, and when the pass rate is less than 80%, repeated grouting shall be carried out.

The construction method of the well in the piezo-transformed tube well in the loess sand and pebble formation with high water richness is convenient, safe and reliable for construction. The operation under the conditions ensures the safety of the operators during the construction process and improves the construction quality of the "well in the well".

In addition, this high-water-rich loess sand and pebble formation piezo-transformer tube well construction method has good sealing quality and improves the structural durability of weak parts. Double-liquid grouting is carried out in the most stressed parts such as the well body, the pipe body and the nozzle joint, so as to prevent fatigue cracks. Weak areas should be fully wrapped and reinforced to ensure that even if the downstream sewage treatment plant operates abnormally for a long time, the pipe body is subject to alternate lifting and lowering water hammer pressure and pipe vibration, and the pipe wall and the inspection well body will not crack and cause water outside the well. , sand infiltration, resulting in the collapse of the drainage system around the well, causing deep sandy soil hollowing, loess subsidence, and road surface collapse around the well.

The above is only an embodiment of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, several modifications and improvements can be made, and these should also be regarded as It belongs to the protection scope of the present invention.

Claims (7)

1. A method for constructing a piezo-transformer well in a high-water-rich loess sand pebble stratum, comprising the following steps: a) caisson construction Excavate a counterbore at a predetermined position, and the depth of the counterbore exceeds the predetermined depth of the main pipeline; The reinforced concrete caisson is made on the four walls and bottom wall of the shaft at the lower part of the caisson according to the construction drawings. The caisson is sealed with no drainage. The caisson is made and sunk many times. The side walls of the caisson are reserved for the passage of the main pipeline. hole; b) Pipe jacking construction The pipe sections of the main pipeline are hoisted into the caisson in turn, and the pipe sections of the two main pipes are respectively pushed out from the opening of the caisson through the jacking equipment, and there is a gap between the pipe sections of the two main pipes; c) Measuring and positioning According to the center coordinates of the inspection well in the drawing, the coordinates of the four corners of the caisson are calculated through the structure size and arrangement of the caisson; d) Check the wellbore construction at the bottom of the well Step-by-step construction on site, the first step is to construct the well chamber floor, the second step to construct the well chamber wall, and the third step to construct the reinforced concrete wellbore; Chisel the bottom of the caisson, then pour the bottom concrete of the inspection well, and pre-embed the steel reinforcement of the well wall when pouring the bottom concrete; Before the construction of the inspection well wall, intercept the pipeline according to the distance between the caisson and the inspection well, connect the pipeline on both sides, and pour the foundation. Rebar of the shaft; The wellbore is a square wellbore, and supports are erected from bottom to top to provide a working platform for operators. The pipeline crossing the well wall is filled with linseed tar sand, and the upstream surface is sealed with polysulfide sealant; e) Check the backfill around the wellbore downhole The backfill around the well is backfilled with the sand from the water-falling sand site. When the backfill surface no longer has fine air bubbles, the water injection can be stopped; After the on-site water-falling sand is completed, sample the ring knife at the site in time, obtain the relevant data with the balance and microwave oven drying method, and measure the degree of compaction; The external platform of the wellbore can backfill the surrounding soil of the well room to a certain height in advance. After backfilling to the elevation of the branch pipe, install the branch pipe, and protect the finished product when the branch pipe is backfilled; f) Inspection of wellbore construction and backfilling in the upper part of the well The upper shaft structure of the inspection well is brick masonry. After the reinforced concrete shaft is completed, it is backfilled to the top of the reinforced concrete shaft; g) Construction of road subgrade and sub-base Since the inspection well is within the subgrade range of the road, after the caisson is backfilled to the top of the road bed, the subgrade in the caisson is backfilled and constructed together with the base of the overall road; h) Preparation of slurry and grouting reinforcement The plane position of the drilling hole should be consistent with the plane position of the weak and weak parts inside and outside the caisson, and select multiple points to arrange grouting holes, and the distance between points should be ≤1.0m; The auger rotary drilling machine is used to form the hole, the diameter of the hole is 70mm to 110mm, the allowable deviation of verticality is ±1%, and the hole depth is from the roadbed to the pipe jacking pipe or weak and weak parts; Mix cement: water glass: water in a mass ratio of 1:0.1:1 to prepare a double-liquid slurry. Before use, the double-liquid slurry is evenly mixed and filtered through a screen; The double grout is poured through the grouting pipe. Before pouring, the gap between the outside of the grouting pipe and the orifice should be closed with cement mortar. The medium and double slurries are continuously stirred slowly, the stirring time is less than the initial setting time, the flow rate of grouting is 5~10L/min, the water temperature is controlled between 0 ℃ ~ 30 ℃, and the initial setting time of the double slurries is 55min; i) Maintenance and inspection acceptance Closed traffic management is adopted for the area where grouting is completed, and the surrounding large-scale machinery and vibration machinery are prohibited for construction; 28 days after grouting is completed, the inspection is carried out, and the standard penetration method is used for inspection. The grouting inspection point is 3% of the number of grouting holes. When the pass rate is less than 80%, repeated grouting is performed. 2. the high-water-rich loess sand and pebble formation piezo-transformer tube well construction method according to claim 1, is characterized in that: In the step d), the construction of the lower wellbore is checked, and the lower wellbore is about 3m high for one pouring, and the construction can be divided into sections larger than 3m. 3. the construction method in a piezo-transformer tube well in a high-water-rich loess sand pebble stratum according to claim 1, is characterized in that: In the step e), the construction of the upper wellbore of the inspection well is checked, and the inner and outer well walls of the upper wellbore are plastered with 1:2 cement mortar and 5% waterproofing agent with a thickness of 20 mm. 4. the high-water-rich loess sand and pebble stratum piezo-transformer tube well construction method according to claim 1, is characterized in that: In the step h) preparation of slurry and grouting reinforcement, the stirring time in preparing the slurry should be greater than 2 minutes, the water-cement ratio should be controlled at 0.8 to 1, and then a certain amount of water glass should be mixed into the mixing bucket according to the volume of the slurry mixing bucket. The solution is stirred evenly, and the volume ratio of water glass and cement slurry is controlled between 0.5 and 0.8. 5. the high-water-rich loess sand and pebble stratum piezo-transformer tube well construction method according to claim 1, is characterized in that: In the step h) preparation of slurry and grouting reinforcement, according to the area of the caisson, the grouting holes are arranged in a plum blossom shape, and the hole depth is from the roadbed to the pipe joint, and the auger is used for rotary drilling. Degree tolerance is ±1%. 6. The construction method for a piezo-transformer tube well in a high-water-rich loess sand pebble stratum according to claim 1, is characterized in that: The caisson cover is prefabricated, and the through hole at the top of the inspection well is reserved on the caisson cover. After h) slurry preparation and grouting reinforcement, the caisson cover is covered on the upper side of the caisson. 7. The construction method for a piezo-transformer tube well in a high-water-rich loess sand pebble stratum according to claim 1, is characterized in that: In the step h), the grouting pipes are divided into several first grouting pipes and several second grouting pipes, and the several first grouting pipes are divided into two groups, and the two groups of first grouting pipes correspond to the pipe joints on both sides, The lower ends of each group of first grouting pipes extend to the upper side of the pipe sections inside and outside the caisson; the lower ends of several second grouting pipes extend to the periphery of the connection between the upper wellbore and the lower wellbore of the inspection well.

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