CN107313438B - Well formation construction method for dewatering well in area with complex geological conditions - Google Patents
Well formation construction method for dewatering well in area with complex geological conditions Download PDFInfo
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Abstract
The invention provides a well construction method of a dewatering well in a region with complex geological conditions, which comprises the steps of performing construction preparation, reverse circulation hole guiding, steel perforated pipe burying, punching and drilling hole forming and hole cleaning by adopting devices such as an air down-the-hole hammer, a screw air compressor, a water pump, a long spiral drill rod, a steel perforated pipe and the like. Therefore, the steel perforated pipe is embedded by adopting reverse circulation hole leading, the gap between the steel perforated pipe and the hole wall is backfilled by hydrophobic stone, and the hole is continuously formed by adopting a down-the-hole hammer after the construction is carried out until the lower chalk series mudstone reaches the design required precipitation shaft bottom elevation. Therefore, by combining and applying the reverse circulation construction technology and the down-the-hole hammer construction technology and adopting the improved steel perforated pipe as the technology connection technology, the well completion construction efficiency and the well completion success rate are improved.
Description
Technical Field
The invention relates to the technical field of dewatering well completion, in particular to a construction method for dewatering well completion in an area with complex geological conditions.
Background
In the course of river regulation, the geology of the Yitong river in Changchun City in China is found to be mainly composed of three sets of stratums, the upper part is artificially filled with soil, the middle part is a fourth series of cohesive soil and sand layer, the lower part is chalk series mudstone, the properties of the ground soil are not changed greatly, the geology is divided into 6 main layers and 5 sub-layers according to the formation age, cause type and engineering properties, wherein, the 1 st layer of powdery clay and the 2 nd layer of organic powdery clay of the ② main layer are lacked, and the characteristics and basic distribution rule of other ground soil are divided into the following according to the sequence of drilling and revealing as shown in figure 1:
①, the main layer is artificial filling and surface water, which can be divided into the following layers:
layer 1: the water is distributed in the pond, the thickness of the layer is 1.70-4.00 m, and the elevation of the bottom of the layer is 189.03-191.33 m.
Layer 2: the miscellaneous filling soil is similar to modern artificial filling, has miscellaneous color of gray black, takes the clay as the main material, and contains small stones, broken bricks and the like. Loose, slightly wet, and uneven soil texture. The layer thickness is 1.70-2.80 m, and the layer bottom elevation is 192.02-193.54 m.
Layer 3: the plain filling soil is nearly modern natural accumulation, is black, mainly comprises cohesive soil and contains plant roots. Loose, slightly wet, and uneven soil texture. The layer thickness is 1.90-2.70 m, and the layer bottom elevation is 191.86-192.79 m.
Layer 4: the soil filled with impurities is filled by modern workers, is ash-ash black, mainly comprises silt, contains organic matters, and is filled with a large amount of stones, broken bricks and the like. Loose, saturated and uneven soil texture. The layer is distributed in the fishpond, the thickness of the layer is 0.50-3.30 m, and the bottom elevation of the layer is 188.03-192.25 m.
③ the main layer is coarse sand, the fourth system is alluvial substance, gray, slightly dense to medium dense, slightly dense as main, saturated, the components are quartz and feldspar as main, the grain diameter is coarse sand as main, the lower part is gravel sand and gravel, the particles gradually become bigger from top to bottom, the roundness is poor, the gradation is not uniform, the layer thickness is 1.10-4.10 m, and the layer bottom elevation is 188.33-191.15 m.
④ the main layer is argillaceous siltstone, chalk series sedimentary rock, completely weathered, mainly grayish green argillaceous siltstone, including mauve silty argillaceous rock, irregular, interbedded structure, argillaceous-sandy structure, wherein the sandstone mainly comprises quartz feldspar, has large local debris particles, basically destroyed structure, most weathered sands and blocks, the argillaceous rock mainly comprises clay minerals, basically destroyed structure, and most weathered hard plastic clays, the layer has poor cementability, can be kneaded by hand, is easy to disintegrate after being soaked in water and dried in air, has softening property, has V-level rock mass quality basic level, is distributed in the whole field, the layer thickness is 2.10-3.70 m, and the bottom elevation is 185.63-188.65 m.
⑤ the main layer is silty mudstone, chalk series sedimentary rock, strong weathering, mainly mauve mudstone, with gray white sandstone, irregular, interbedded structure, and muddy-sandy structure, wherein the mudstone mainly comprises clay minerals, most of the structure is destroyed, weathering cracks develop, the core is short column, the silty sandstone mainly comprises quartz feldspar, most of local debris particles are destroyed, the layer is poor in cementation, the auger drill can drill, is easy to disintegrate after being soaked in water and dried in air, has softening property, partially adheres calcium hard sandstone, is compact and hard, the basic quality grade of rock mass is V grade, the whole field is distributed, the thickness is 4.90-6.60 m, and the bottom elevation is 179.03-182.65 m.
⑥ the main layer is argillaceous siltstone, chalk-based sedimentary rock, medium weathering, mainly grayish green argillaceous siltstone, including mauve silty argillaceous rock, irregular, interbedded structure, sandy-argillaceous structure, wherein the sandstone mainly comprises quartz feldspar, has large local clastic particles and does not develop weathering cracks, the argillaceous rock mainly comprises clay minerals and is columnar, argillaceous cementation and poor cementation are easy to disintegrate after being soaked in water and air-dried, the argillaceous rock is softened and is locally cemented with calcium to be hard, the basic quality grade of the rock is V-grade, the maximum layer thickness is 13.00m, the environmental water along the line of the planned engineering is mainly surface water and underground water, the surface water is pond water, and the underground water is pore diving and chalky-based fissure water.
Further, surface water, pore diving and bedrock fracture water in the geology of Itong river have the following characteristics through exploration:
(1) surface water: is discharged by atmospheric precipitation and lateral runoff supply, evaporation and lateral runoff modes.
(2) Pore diving: the soil is added into the near modern artificial filling (strong permeable layer), the fourth series of cohesive soil layers (weak permeable layer) and the sandy soil layers (strong permeable layer).
(3) Bed rock fracture water: the water-retaining agent is mainly added in completely-weathered chalk series mudstone, has small water content and has hydraulic connection with fourth series pore diving.
The exploration period is a water-enriching period, the underground initial water level is 1.60-2.40 m, and the elevation is 192.55-192.96; the stable water level of the underground water is 1.50-2.20 m, the elevation is 193.03-193.13 m, and the elevation of the surface water is 193.03 m.
It is worth noting that the traditional well forming process basically adopts a reverse circulation drilling machine to form a well at one time, however, in the face of the complex geological conditions of the Yitong river, the well forming difficulty is high, only a single process is adopted to form the well, the construction efficiency is low, and the well forming success rate is reduced, so that a well-forming construction method of the dewatering well applicable to the complex geological conditions area needs to be provided.
Disclosure of Invention
In view of the above situation, the invention provides a well completion construction method for a dewatering well in a region with complex geological conditions, which comprises the steps of artificially filling soil at the upper part, filling fourth series of cohesive soil and sand layers in the middle part, adopting reverse circulation hole guiding, embedding steel flower pipes, backfilling gaps between the steel flower pipes and the wall of a hole by using hydrophobic stones, and continuously forming holes by using a down-the-hole hammer after constructing to lower chalk series mudstones until the design required elevation of the bottom of the dewatering well is reached, so that the well completion construction efficiency and the well completion success rate are effectively improved.
In order to achieve the aim, the technical scheme adopted by the invention is to provide a well construction method of a dewatering well in a region with complex geological conditions, wherein the geological conditions comprise an upper part formed by artificial filling, a middle part formed by a fourth series of cohesive soil and sand layers and a lower part formed by chalk series of mudstone; the well construction method of the dewatering well comprises the following steps:
construction preparation: after the construction site is leveled, confirming a construction control point; logging well-releasing sites according to the control points, and measuring and setting permanent control points in a region which is not influenced by well drilling;
and (3) reverse circulation hole guiding: moving the pilot hole pile driver to reach the designated well position centering and adjusting the verticality of the long spiral drill rod, so that the drill rod is vertically aligned with the well position center; drilling, and when the drilling is carried out to the designed depth, making a striking mark at the position of the drilling machine tower body corresponding to the position where the power head bottom surface stays, wherein the striking mark is used as a basis for controlling the well length in the construction process; after the previous well is constructed, repeating the steps to lead the hole at the next position;
embedding a steel perforated pipe: in the process of drilling the long spiral drill rod, the down-the-hole hammer is vibrated along with the rotation of the drill rod, so that a steel perforated pipe which is sleeved outside the air down-the-hole hammer in advance is driven, the steel perforated pipe and the down-the-hole hammer are synchronously followed before entering a rock stratum, the steel perforated pipe is buried into a hole leading position, and a gap between the steel perforated pipe and the wall of the hole leading hole is filled with hydrophobic fine stones;
punching and drilling to form a hole: starting the screw air compressor, and starting an internal and external power head of the drilling machine to drill by rotating and vibrating the down-the-hole hammer when the air pressure reaches a preset pressure; the steel perforated pipe is made to follow the down-the-hole hammer to the rock stratum along with the footage of the down-the-hole hammer, then the outer power head is closed, the pipe following is stopped, and the inner power head drives the down-the-hole hammer to continue to drill into the rock stratum to the designed hole depth;
hole cleaning: after the drill hole reaches the designed hole depth, the bottom of the down-the-hole hammer is cleaned by air pressure so as to lift along with the long spiral drill rod to remove sediments; and stopping after the depth of the hole and the thickness of the sediment are detected to be less than or equal to 50mm and meet the design requirements.
In the embodiment of the method, in the reverse circulation hole guiding step, when the hole guiding pile machine is centered, a marking rod is inserted into the center point of the hole according to the design requirement after the hole guiding well is positioned.
In the method embodiment of the invention, in the reverse circulation hole leading step, when the verticality of the drill rod is adjusted, the guide rods of the tower body are checked by using the front and back vertical marker posts and the left and right vertical marker posts of the tower body of the pile machine, and the position is corrected, so that the drill rod is vertically aligned with the center of a well position, and the hole leading length with the verticality less than 1.0 percent is ensured.
In the method embodiment of the invention, in the step of punching and drilling the hole, the outer power head drills the upper part of the formed drill hole, and the inner power head drills the lower part of the formed drill hole.
In the embodiment of the method, the drill is slowly advanced at a constant speed in the drilling process, and the down-the-hole hammer is lifted upwards when the resistance is high, wherein the lifting distance is about 0.3-0.5 m; and impacting the feed ruler along with the rotary vibration again, drilling the hole to the depth of 5-8 m, lifting the long spiral drill rod to remove the drilling slag once, drilling the hole to the depth of 10m to remove the drilling slag for the second time, and continuously drilling until the hole depth reaches the design requirement.
In the method embodiment of the invention, in the drilling step, the drilling parameters comprise that a 330HP air compressor is adopted, the air pressure of 12MPa is adopted in the drilling process, the parameter value of an ammeter entering a rock stratum is 220A, and the air pressure value of a down-the-hole hammer is 2.41-3 MPa.
In the method embodiment of the invention, in the step of punching and drilling holes, when the pressure of the air compressor reaches 12MPa, the holes are cleaned by utilizing air pressure, so that the efficiency of removing the drilling slag by the long spiral drill rod is improved.
In the embodiment of the method, in the hole cleaning step, when the thickness of the sediment is detected to be more than 50mm, the down-the-hole hammer is lowered into the hole again for secondary hole cleaning until the actual requirement is met.
In the method embodiment of the invention, in the hole cleaning step, the end part of the down-the-hole hammer head is provided with a slag discharging channel, the chiseled slag can be discharged onto the long spiral drill rod from the slag discharging channel by using pressure air as a medium, the long spiral drill rod is lifted, and the drilled slag can be directly discharged to the outside of the hole to complete hole cleaning of the drilled hole.
In the embodiment of the method, the arrangement interval of the dewatering wells is 15-30 m.
Drawings
FIG. 1 is a schematic diagram of the construction method of the present invention.
FIG. 2 is a schematic diagram of the construction depth of the dewatering well according to the present invention and the geological conditions.
FIG. 3 is a schematic structural view of the steel perforated pipe of the present invention.
Fig. 4 is a plane sectional structure schematic diagram of the dewatering well of the present invention.
The correspondence of reference numerals to components is as follows:
a steel perforated pipe 10; a dense mesh net 11; a borehole 20; an upper portion 21; a lower portion 22; a filter material 30; a water pump 40; a suction pipe 41.
Detailed Description
To facilitate an understanding of the present invention, the following description is made in conjunction with the accompanying drawings and examples.
Referring to fig. 1 to 4, the method for constructing the precipitation well in the complicated geological condition area comprises the steps of guiding the hole in a reverse circulation mode, burying the steel perforated pipe, backfilling a gap between the steel perforated pipe and the hole wall with hydrophobic stone, and continuously forming the hole by using a down-the-hole hammer after constructing the lower chalk-based mudstone until the designed precipitation well bottom elevation is achieved. Therefore, by combining and applying the reverse circulation construction technology and the down-the-hole hammer construction technology and adopting the improved steel perforated pipe as the technology connection technology, the well completion construction efficiency and the well completion success rate are improved.
As shown in fig. 1, the arrangement interval of the dewatering wells of the present invention is preferably 15 to 30 m. As shown in fig. 2, the construction structure of the present invention comprises a steel perforated pipe 10, a drilling hole 20, a filter material 30 and a water pump 40, wherein the steel perforated pipe 10 is as shown in fig. 2, 3 and 4, and a dense mesh net 11 is arranged outside the steel perforated pipe; the bore 20 comprises an upper portion 21 and a lower portion 22; the water pump 40 is arranged at the lower part 22 of the drill hole 20 and is communicated to the outside of the wellhead of the dewatering well through a water pumping pipe 41.
The concrete construction method comprises the steps of adopting an air down-the-hole hammer, a screw air compressor, a water pump, a long spiral drill rod, a steel perforated pipe and the like to carry out construction preparation, reverse circulation hole leading, steel perforated pipe embedding, drill punching hole forming and hole cleaning.
The construction preparation step specifically includes:
1) and carrying out construction lofting after the construction site is leveled, rechecking the construction control point before lofting, setting a fixed leveling point of the dewatering well construction project on the construction site, protecting the measurement point location, and frequently checking to prevent the precision reduction caused by the damage of the point location or other reasons.
2) Well site locations were lofted using GPS.
3) The elevation of the well is strictly controlled, and the elevation record is needed after each well is finished.
4) And logging well placement sites according to the control points, and simultaneously measuring and setting two permanent control points in a region which is not influenced by well drilling, wherein the permanent control points are used for checking and correcting axis points or rechecking well positions in the construction process. The construction axis must be guided and measured strictly according to the design coordinate point, and confirmed after many rechecks. The position of the axis control point of the construction site is required to be arranged at a place which is not influenced by well drilling operation and is protected.
5) And numbering the wells one by one according to the designed well pattern and the construction sequence.
Through the construction preparation step, the well position of the precipitation well is accurately confirmed, so that the distance between the precipitation wells is ensured, and the precipitation effect of the precipitation well is improved.
The reverse circulation hole guiding step specifically comprises the following steps:
1) and (3) positioning and centering the pile driver, inserting a marker post on the center point of the pile according to design requirements after the pilot hole well is positioned, moving the pilot hole pile driver to reach an appointed well position after the well position is placed, centering, and adjusting the verticality of the drill rod.
2) After the pile driver is in place, the guide rods of the tower body are checked by using the vertical marker posts arranged at the front, the back, the left and the right of the tower body of the pile driver, and the position is corrected, so that the drill rod is vertically aligned with the center of the well position, and the length of a pilot hole with the verticality of the drill rod less than 1.0% is ensured. And the next procedure is carried out after the inspection of managers is qualified.
3) When drilling begins, the valve of the drill bit is closed, the drill rod is moved downwards until the drill bit touches the ground, and the motor is started to drill. Preferably, the drill is rotated at a slow speed and then at a fast speed to reduce drill pipe wobble and to facilitate checking for deviations from the drilled hole for timely correction. In the pore-forming process, if the drill rod shakes or is difficult to drill, the footage should be slowed down to avoid the conditions of drill hole deflection, displacement, even damage to the drill rod, a drilling tool and the like. When the drilling machine drills to the designed depth, the position of the drilling machine tower body corresponding to the position where the power head stays on the bottom surface is marked in a striking mode to serve as the basis for controlling the well length in construction. During formal construction, the well length when the bottom surface of the power head reaches the marked part meets the design requirement. During construction, the height difference of the bearing platform needs to be considered, and the bearing platform is correspondingly increased and decreased.
4) And after the previous well is constructed, repeating the steps to lead the hole at the next position.
Because the probability of hole collapse caused by the down-the-hole hammer during the construction of the soft soil foundation is too high, the long spiral guide hole is ensured to be led to a hard rock stratum during the construction. And (3) leading the hole by reverse circulation to ensure the perpendicularity of the long spiral hole, and further, continuously turning the hole for about 3 minutes after the hole is led to the hard rock stratum to ensure that the hole is led to the hard rock stratum.
The steel perforated pipe embedding step specifically comprises the following steps:
embedding the prepared steel flower tube at the position of the long spiral lead hole formed in the previous step, and filling the gap between the steel flower tube and the wall of the lead hole with hydrophobic fine stones. Specifically, the steel floral tube may be embedded in the pilot hole using a 220 excavator.
In the embodiment of the invention, the outside of the steel perforated pipe is also coated with a dense mesh net. As shown in fig. 3 and 4, a schematic structural diagram of the steel perforated pipe 10 of the present invention with a 200-mesh dense mesh net 11 is shown; the outer diameter of the steel perforated pipe 10 is preferably 200mm, and the aperture of the long spiral lead hole is 400 mm.
The embedding verticality of the steel perforated pipe and the wall protection and water filtration functions of the steel perforated pipe are ensured through the steel perforated pipe embedding step.
The step of punching and drilling holes specifically comprises the following steps:
the air compressor is started firstly, when the air pressure reaches 12MPa, the down-the-hole hammer vibrates along with rotation, and the internal and external power heads of the drilling machine are started to drill. In order to prevent hole deviation, slow impact is adopted when holes are formed; meanwhile, a 220-type excavator is required to be matched with a steel perforated pipe, and the steel perforated pipe solves the problems of hole collapse, drill jamming or drill burying and upper layer water filtration of a well hole. The steel perforated pipe follows to the bedrock surface along with the depth of the down-the-hole hammer, then the outer power head is closed, the pipe following is stopped, and the down-the-hole hammer continues to drill into the rock to the designed hole depth.
In the embodiment of the present invention, as shown in fig. 2, the outer power head drills an upper portion 21 forming the drill hole 20, and the inner power head drills a lower portion 22 forming the drill hole 20; preferably, the bore hole 20 has an upper portion 21 with a bore diameter of 400mm and a lower portion 22 with a bore diameter of 150mm, wherein the bore hole 20 is formed by embedding a steel flower pipe with a diameter of 200mm in the bore hole 21 with the bore diameter of 400mm, and a filter material is arranged between the bore wall of the upper portion 21 of the bore hole 20 and the steel flower pipe 10, and the bore hole 22 of the lower portion 20 is formed by collecting and draining water from a bare bore hole with a bore diameter of 150mm because the bore hole is already in the strongly weathered and moderately weathered chalky sedimentary rocks.
In an embodiment of the present invention, the step of drilling a hole further includes:
in the drilling process, uniform slow advance is adopted, and when the resistance is large, the down-the-hole hammer is lifted upwards by a lifting distance of about 0.3 to 0.5 m; and impacting the feed ruler along with the rotary vibration again, drilling the hole to the depth of 5-8 m, lifting the long spiral drill rod to remove the drilling slag once, drilling the hole to the depth of 10m to remove the drilling slag for the second time, and continuously drilling until the hole depth reaches the design requirement.
Further, when the pressure of the air compressor reaches 12MPa, the air pressure is used for cleaning the holes for 2-3 minutes so as to improve the efficiency of removing the drilling slag by the long spiral drill rod.
In an embodiment of the present invention, the drilling parameters include: an air compressor adopting 330 HP; the air pressure of 12MPa is adopted in the drilling process; the value of an ammeter parameter entering a rock layer is 220A; the down-the-hole hammer air pressure value is 2.41 to 3 MPa. In addition, the drilling machine is forbidden to move in the drilling process, and the stability of the frame is required to be kept; and (5) finishing the hole after the hole depth and the hole bottom sediments are detected to meet the requirements.
In the embodiment of the invention, the reverse circulation hole leading step, the steel perforated pipe embedding step and the punching drilling hole forming step are realized by adopting an air down-the-hole hammer, a screw air compressor, a water pump, a long spiral drill rod and a steel perforated pipe. Specifically, the drill model of the air down-the-hole hammer adopted by the invention is MZ 150; the screw air compressor adopted by the invention has the model number of LT-175A and the volume flow of 20m3Min, counting one to meet the requirements of drilling, slag discharging and hole cleaning; the number of the water pumps is two, and the power is 3 KW; the long spiral drill rod is used for lifting and deslagging, and slag generated by drilling is discharged from a slag discharge hole of the down-the-hole hammer; the steel perforated pipe is used for playing a good wall protection role and a good water filtering role between the reverse circulation hole leading step and the drill punching hole forming step, and can connect two types of dewatering well completion processes besides preventing drill jamming, burying and improving drilling efficiency.
More specifically, before the steel perforated pipe enters the rock stratum, the down-the-hole hammer and the steel perforated pipe should be kept to synchronously follow, and the long spiral drill rod is pulled up for 1-2 times to remove slag and clean holes, which is particularly important in a large-block-diameter sand-gravel layer; the rock-entering depth of the steel perforated pipe should be controlled within the range of 20cm maximally entering the rock layer so as to reduce friction between the steel perforated pipe and the rock wall and prolong the service life of the steel perforated pipe drill bit. And after the steel perforated pipe is buried, filter materials such as hydrophobic fine sand and the like are filled in time.
Through the hole forming step by punching and drilling, the air pressure of an air compressor is adjusted in time for down-the-hole hammer leading hole, so that the hole collapse phenomenon caused by overlarge air pressure is avoided.
The hole cleaning step specifically comprises:
and (3) after the hole is drilled to the designed hole depth, cleaning the hole bottom of the down-the-hole hammer for 2-3 minutes by air pressure, lifting along with the long auger stem to remove sediments, and stopping when the hole depth and the sediment thickness are detected to be less than or equal to 50mm and meet the design requirements. And when the thickness of the sediment is detected to be more than 50mm, the down-the-hole hammer is put into the hole again to carry out secondary hole cleaning until the actual requirement is met.
Specifically, a slag discharging channel is arranged at the end part of the down-the-hole hammer head of the drilling machine, chiseled slag can be discharged onto the long spiral drill rod from the slag discharging channel by taking pressure air as a medium, the long spiral drill rod is lifted, the drilled slag can be directly discharged to the outside of the hole, hole cleaning of the drilled hole is completed, and after the hole is cleaned by high-pressure high-speed pressure air, the bottom of the hole is cleaned up, so that no sediment exists.
The invention relates to a well construction method of a dewatering well in a region with complex geological conditions, which adopts reverse circulation hole leading to embed a steel flower pipe in complex geological with artificially filled soil at the upper part and fourth series of cohesive soil and sand layer at the middle part, backfills a gap between the steel flower pipe and a hole wall by a hydrophobic stone, and adopts a down-the-hole hammer to continue to form a hole after construction to lower chalk series mudstone until reaching the design required elevation of the dewatering well bottom, thereby effectively improving the well construction efficiency and the well success rate.
In addition, when the well construction method of the dewatering well is implemented on site, the reverse circulation hole leading and the steel perforated pipe and the down-the-hole hammer are prepared in advance, the construction procedures are reasonably arranged, hole collapse caused by the time gap process after hole leading is avoided, and the two processes are reasonably and timely connected.
While the present invention has been described in detail and with reference to the accompanying drawings and examples, it will be apparent to one skilled in the art that various changes and modifications can be made therein. Therefore, certain details of the embodiments are not to be interpreted as limiting, and the scope of the invention is to be determined by the appended claims.
Claims (10)
1. A well construction method of a dewatering well in a region with complex geological conditions comprises the steps of forming an upper part by artificial filling, forming a middle part by a fourth series of cohesive soil and sand layer and forming a lower part by chalk series mudstone; the method is characterized by comprising the following steps:
construction preparation: after the construction site is leveled, confirming a construction control point; logging well-releasing sites according to the control points, and measuring and setting permanent control points in a region which is not influenced by well drilling;
and (3) reverse circulation hole guiding: moving the pilot hole pile driver to reach the designated well position centering and adjusting the verticality of the long spiral drill rod, so that the drill rod is vertically aligned with the well position center; drilling to ensure that the guide hole of the long spiral drill rod is led to a hard rock stratum, and when the drill reaches the designed depth, making a striking mark at the position of the drilling machine tower body corresponding to the stop position of the bottom surface of the power head to be used as a basis for controlling the well length in construction; after the previous well is constructed, repeating the steps to lead the hole at the next position;
embedding a steel perforated pipe: in the process of drilling the long spiral drill rod, the down-the-hole hammer is vibrated along with the rotation of the drill rod, so that a steel perforated pipe which is sleeved outside the air down-the-hole hammer in advance is driven, the steel perforated pipe and the down-the-hole hammer are synchronously followed before entering a rock stratum, the steel perforated pipe is buried into a hole leading position, and a gap between the steel perforated pipe and the wall of the hole leading hole is filled with hydrophobic fine stones;
punching and drilling to form a hole: starting a screw air compressor, and starting an internal and external power head of a drilling machine to drill by rotating and vibrating a down-the-hole hammer when air pressure reaches a preset pressure; the steel perforated pipe is made to follow the down-the-hole hammer to the rock stratum along with the footage of the down-the-hole hammer, then the outer power head is closed, the pipe following is stopped, and the inner power head drives the down-the-hole hammer to continue to drill into the rock stratum to the designed hole depth;
hole cleaning: after the drill hole reaches the designed hole depth, the bottom of the down-the-hole hammer is cleaned by air pressure so as to lift along with the long spiral drill rod to remove sediments; and stopping after the depth of the hole and the thickness of the sediment are detected to be less than or equal to 50mm and meet the design requirements.
2. The well construction method of a dewatering well in a complicated geological condition area according to claim 1, characterized in that:
in the reverse circulation hole leading step, when the hole leading pile machine is centered, a marking rod is inserted into the center point of the hole according to the design requirement after the hole leading well is positioned.
3. The well construction method of a dewatering well in a complicated geological condition area according to claim 1, characterized in that:
in the reverse circulation hole leading step, when the verticality of the drill rod is adjusted, the guide rods of the tower body are checked by using vertical marker posts arranged at the front and back and the left and right of the tower body of the pile machine, and the position is corrected, so that the drill rod is vertically aligned with the center of a well position, and the verticality is ensured to be less than 1.0% of the hole leading length.
4. The well construction method of a dewatering well in a complicated geological condition area according to claim 1, characterized in that:
in the step of punching and drilling, the outer power head drills the upper part of the drilled hole, and the inner power head drills the lower part of the drilled hole.
5. The well construction method of dewatering wells in areas with complex geological conditions as claimed in claim 1, wherein the drilling step further comprises:
in the drilling process, uniform slow advance is adopted, and when the resistance is large, the down-the-hole hammer is lifted upwards, wherein the lifting distance is 0.3-0.5 m; and impacting the feed ruler along with the rotary vibration again, drilling the hole to the depth of 5-8 m, lifting the long spiral drill rod to remove the drilling slag once, drilling the hole to the depth of 10m to remove the drilling slag for the second time, and continuously drilling until the hole depth reaches the design requirement.
6. The well construction method of a dewatering well in a complicated geological condition area according to claim 1, characterized in that:
in the step of punching and drilling holes, drilling parameters comprise that a 330HP air compressor is adopted, 12MPa air pressure is adopted in the drilling process, the value of an ammeter parameter entering a rock stratum is 220A, and the value of the down-the-hole hammer air pressure is 2.41-3 MPa.
7. The well construction method of dewatering well in area with complex geological condition as claimed in claim 1 or 6, characterized in that:
in the step of punching and drilling holes, when the pressure of the air compressor reaches 12MPa, the holes are cleaned by utilizing air pressure, so that the efficiency of removing drilling slag by the long spiral drill rod is improved.
8. The well construction method of a dewatering well in a complicated geological condition area according to claim 1, characterized in that:
in the hole cleaning step, when the thickness of the sediment is detected to be more than 50mm, the down-the-hole hammer is put into the hole again for secondary hole cleaning until the actual requirement is met.
9. The well construction method of dewatering well in area with complex geological condition as claimed in claim 1 or 8, characterized in that:
in the hole cleaning step, a slag discharging channel is arranged at the end part of the down-the-hole hammer head, the chiseled slag can be discharged onto the long spiral drill rod through the slag discharging channel by using pressure air as a medium, the long spiral drill rod is lifted, and the drilled slag can be directly discharged to the outside of the hole to complete hole cleaning of the drilled hole.
10. The well construction method of a dewatering well in a complicated geological condition area according to claim 1, characterized in that:
the arrangement interval of the dewatering wells is 15-30 m.
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| JP2009052202A (en) * | 2007-08-23 | 2009-03-12 | Takenaka Komuten Co Ltd | Deep well installation method |
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| JP2009052202A (en) * | 2007-08-23 | 2009-03-12 | Takenaka Komuten Co Ltd | Deep well installation method |
| CN102912806A (en) * | 2012-09-27 | 2013-02-06 | 中交三航局第二工程有限公司 | Construction method of precipitation well |
| CN206052747U (en) * | 2016-08-19 | 2017-03-29 | 中国建筑第六工程局有限公司 | A kind of variable cross-section dewatering well construction based on geological conditions |
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