阅读说明：本技术 桩基成孔钢护筒施工体系及施工方法 (Pile foundation pore-forming steel casing construction system and construction method ) 是由 常乃坤 董祥君 陈卫卫 汪正杰 王中恩 于 2020-08-21 设计创作，主要内容包括：本发明提供了桩基成孔钢护筒施工体系及施工方法,通过导向弧板的内侧壁与钢护筒的外侧壁尺寸匹配设置；护筒对齐组件的上弧板定位卡设在钢护筒顶部；下弧板与钢护筒的内侧壁尺寸匹配设置；上弧板通过竖杆与下弧板固定连接；两个限位弧板结构相对设置在钢护筒上；弹性件的两端分别与限位弧板结构连接；可伸缩定位件的两端分别穿过竖杆,并向外延伸与限位弧板结构抵接；外箍组件的上箍体和下箍体分别设在相邻的钢护筒上。本申请通过设置导向结构和护筒对齐组件,来实现上、下钢护筒的轴向更加精确定位,再通过设置外箍组件来实现上、下钢护筒的固定连接,大大提高了钢护筒的定位安装效率和安装进度,同时大大提高了桩基的成桩效率及成桩质量。(The invention provides a pile foundation pore-forming steel casing construction system and a construction method, wherein the inner side wall of a guide arc plate is matched with the outer side wall of a steel casing in size; the upper arc plate of the pile casing alignment assembly is positioned and clamped at the top of the steel pile casing; the sizes of the lower arc plate and the inner side wall of the steel casing are matched; the upper arc plate is fixedly connected with the lower arc plate through a vertical rod; the two limiting arc plate structures are oppositely arranged on the steel casing; two ends of the elastic piece are respectively connected with the limiting arc plate structure; two ends of the telescopic positioning piece respectively penetrate through the vertical rod and extend outwards to be abutted against the limiting arc plate structure; the upper hoop body and the lower hoop body of the outer hoop assembly are respectively arranged on the adjacent steel casing. This application is through setting up guide structure and protecting a section of thick bamboo alignment subassembly, realizes that the upper and lower steel protects an axial more accurate positioning of section of thick bamboo, and the rethread sets up the outer hoop subassembly and realizes the upper and lower steel and protects a fixed connection of section of thick bamboo, has improved the steel greatly and has protected a location installation effectiveness and the installation progress of section of thick bamboo, has improved the stake efficiency and the quality of forming a stake of pile foundation simultaneously greatly.)

1. Pile foundation pore-forming steel protects a section of thick bamboo construction system, its characterized in that: the device comprises a guide structure, a pile casing alignment assembly and an outer hoop assembly;

the guide structure comprises a guide arc plate; the guide arc plate is positioned outside the pile foundation; the inner side wall of the guide arc plate is matched with the outer side wall of the steel casing in size, and is used for limiting and guiding the outer side edge of the steel casing;

the pile casing alignment assembly comprises a limiting arc plate structure, an elastic piece and a telescopic positioning piece; the limiting arc plate structure comprises an upper arc plate and a lower arc plate; the upper arc plate is positioned and clamped at the top of the steel casing; the sizes of the lower arc plate and the inner side wall of the steel casing are matched; the upper arc plate is fixedly connected with the lower arc plate through a vertical rod; the two limiting arc plate structures are oppositely arranged on the steel casing; two ends of the elastic piece are respectively connected with the limiting arc plate structure; two ends of the telescopic positioning piece respectively penetrate through the vertical rod and extend outwards to be abutted against the limiting arc plate structure;

the outer hoop assembly comprises an upper hoop body and a lower hoop body; the upper hoop body and the lower hoop body are respectively arranged on the adjacent steel casing, and the upper hoop body and the lower hoop body are positioned and connected through the longitudinal steel sheets.

2. The pile foundation pore-forming steel pile casing construction system of claim 1, wherein: the guide structure further comprises a support frame; the supporting frame is positioned on the foundation at the side edge of the foundation pile; the guide arc plate is positioned on the support frame.

3. The pile foundation pore-forming steel pile casing construction system of claim 1, wherein: the elastic piece is a pressure spring; the telescopic positioning piece comprises a penetrating rod and a sleeve; the sleeve is detachably and fixedly connected to the two axial ends of the penetrating rod.

4. The pile foundation pore-forming steel pile casing construction system of claim 3, wherein: the sleeve is in threaded connection with the two axial ends of the penetrating rod, and the telescopic positioning piece is stretched through the threaded connection of the sleeve on the penetrating rod.

5. The pile foundation pore-forming steel pile casing construction system of claim 3, wherein: the compression spring is sleeved on the penetrating rod, and two axial ends of the compression spring are respectively abutted and limited with the inner side of the vertical rod.

6. The pile foundation pore-forming steel pile casing construction system of claim 3, wherein: the penetrating rod is further provided with scale marks along the axial direction, and the scale marks are arranged in a centrosymmetric mode.

7. The pile foundation pore-forming steel pile casing construction system of claim 1, wherein: the outer hoop assembly is used for fixing the bottom of the upper protective cylinder and the top of the lower protective cylinder; the back of the connecting clamping piece is provided with a notch into which the hoop piece is inserted.

8. The pile foundation pore-forming steel pile casing construction system of claim 1, wherein: a radial L-shaped fixed slat is also arranged; the fixed lath is L-shaped, one end of the fixed lath is provided with a vertical steel plate, and a steel casing is welded with a steel plate with holes at the top of the fixed lath after being embedded.

9. The pile foundation pore-forming steel pile casing construction system of claim 1, wherein: the lower parts of the vertical rods are connected through springs.

10. A pile foundation pore-forming steel pile casing construction method, based on any one of the pile foundation pore-forming steel pile casing construction systems of claims 1-9, characterized by comprising the following steps:

s1, construction preparation: leveling a field, clearing sundries, preparing materials required by construction and binding a reinforcement cage;

s2, measurement and positioning: determining a hole site center pile by using a total station and a steel ruler, arranging guide arc plates around the pile site, reinforcing the pile guard by using cement mortar, and establishing an obvious mark;

s3, setting the ultra-long steel casing: installing the pile casing in sections according to the thickness of a soft soil layer on the earth surface, wherein the diameter of each section of steel casing is increased by 20cm compared with the designed pile diameter, and the length of each section is 2 m; preliminarily judging the embedding depth of the steel casing according to geological survey data, calculating the number of sections required by the steel casing, wherein the steel casing is required to enter a field in advance, and the steel casing is embedded and penetrates through a soft soil layer;

s4, embedding a lower steel casing: after the setting position of the lower protective barrel is determined, a guide structure is arranged on the side of the designed position of the protective barrel, the steel protective barrel is placed down by using a crane, one side of the steel protective barrel is placed down along a guide arc plate, the plane position deviation of the steel protective barrel is controlled within 5cm, and the gradient deviation is controlled within 1%;

s5, lowering the rear section of steel casing: a pile casing alignment assembly is arranged in the upper pile casing, an upper arc plate of the pile casing alignment assembly is clamped at the top of the upper pile casing, and the steel pile casing is lowered down, so that the upper pile casing slides down along the guide arc plate to be aligned with the lower pile casing;

s6, welding and installing the connecting outer hoop device: installing semicircular hoops at the bottom of the upper pile casing and the top of the lower pile casing respectively, penetrating the two ends of each semicircular hoop through the connecting clamping pieces to be fastened and then welding, and welding and fixing the upper connecting clamping piece and the lower connecting clamping piece through longitudinal steel sheets after the two pile casings are welded in alignment;

s7, the last section of steel casing: when a section of protection cylinder is embedded, the high ground of the top surface of the protection cylinder is ensured to be 0.3m, and the ground water level at the high position is ensured to be 2 m; welding a steel plate with holes on the top of the pile casing, and fixing the steel pile casing with the soil nails after fixing the L-shaped soil nail fixing strip and the steel pile casing;

s8, positioning a drilling machine: after the percussion drill rig is installed, the center of a drill bit is accurately aligned to the cross center of the casing, the drill bit is lifted and slowly placed into the steel casing, a slurry pump is started, and the percussion is started after a certain amount of slurry is delivered into the hole;

s9, drilling: when the karst stratum is approached, the prepared mud is confirmed to be sufficient before breakdown, and the phenomenon that the mud is suddenly lost after the karst cave is broken down to cause insufficient pressure in the hole to form hole collapse is avoided; the geological inspection and rechecking of the drill hole are enhanced, and the working condition of the drilling machine, the surrounding ground surface settlement and the water level change in the casing are closely observed;

s10, final hole and hole cleaning: cleaning holes by adopting a pulp changing and hole cleaning method; the height of a water head in the hole is ensured to be kept in the hole cleaning process, and hole collapse is prevented;

s11, lowering a reinforcement cage: after hole cleaning is finished, putting down the reinforcement cage, and fixing the top of the reinforcement cage by using a fixing device;

s12, pouring concrete: and concrete pouring is realized by utilizing an automobile pump.

Technical Field

The invention relates to the technical field of pile foundation construction, in particular to a pile foundation pore-forming steel casing construction system and a construction method.

Background

The highway is mostly in hills, mountain ridge karst area, its topography, landform and hydrogeological conditions are complicated and diversified, especially karst area karst landform distributes extensively, however pile foundation construction scheme usually needs to decide according to the geological conditions in construction area, the pile foundation construction of karst cave has unpredictability, danger, especially the pile foundation construction of string form multilayer karst cave, compare traditional pile foundation construction, need pay attention to the stability of steel casing, the bearing capacity of pile foundation etc. in order to ensure highway or bridge holistic bearing capacity, avoid appearing the later stage and subside scheduling problem.

The steel casing construction of the conventional karst area pile foundation usually adopts an overlong steel casing and finally adopts a concrete pouring pile-forming mode for construction. If the steel casing is not long enough or completely connected when the super-long steel casing is connected, water gushing is easily caused, and other common problems such as slurry leakage, deflection, drill sticking, pile breaking and the like are caused. Therefore, an improved steel casing construction method needs to be developed to solve the above construction problems and improve pile-forming efficiency and pile-forming quality of the pile foundation.

Disclosure of Invention

The invention aims to provide a pile foundation pore-forming steel casing construction system and a construction method, aiming at improving the efficiency and the precision of the butt joint of steel casings.

In order to achieve the purpose, the invention is realized by the following technical scheme:

the pile foundation pore-forming steel pile casing construction system comprises a guide structure, a pile casing alignment assembly and an outer hoop assembly;

the guide structure comprises a guide arc plate; the guide arc plate is positioned outside the pile foundation; the inner side wall of the guide arc plate is matched with the outer side wall of the steel casing in size, and is used for limiting and guiding the outer side edge of the steel casing;

the pile casing alignment assembly comprises a limiting arc plate structure, an elastic piece and a telescopic positioning piece; the limiting arc plate structure comprises an upper arc plate and a lower arc plate; the upper arc plate is positioned and clamped at the top of the steel casing; the sizes of the lower arc plate and the inner side wall of the steel casing are matched; the upper arc plate is fixedly connected with the lower arc plate through a vertical rod; the two limiting arc plate structures are oppositely arranged on the steel casing; two ends of the elastic piece are respectively connected with the limiting arc plate structure; two ends of the telescopic positioning piece respectively penetrate through the vertical rod and extend outwards to be abutted against the limiting arc plate structure;

the outer hoop assembly comprises an upper hoop body and a lower hoop body; the upper hoop body and the lower hoop body are respectively arranged on the adjacent steel casing, and the upper hoop body and the lower hoop body are positioned and connected through the longitudinal steel sheets.

As a further improvement of the present invention, the guiding structure further comprises a supporting frame; the supporting frame is positioned on the foundation at the side edge of the foundation pile; the guide arc plate is positioned on the support frame.

As a further improvement of the invention, the elastic member is a compression spring; the telescopic positioning piece comprises a penetrating rod and a sleeve; the sleeve is detachably and fixedly connected to the two axial ends of the penetrating rod.

As a further improvement of the invention, the sleeve is in threaded connection with two axial ends of the through rod, and the telescopic positioning piece is extended and retracted by virtue of threaded connection of the sleeve on the through rod.

As a further improvement of the invention, the compression spring is sleeved on the penetrating rod, and two axial ends of the compression spring are respectively abutted against the inner side of the vertical rod for limiting.

As a further improvement of the invention, the penetrating rod is also provided with scale marks along the axial direction, and the scale marks are arranged in a central symmetry manner.

As a further improvement of the invention, the outer hoop assembly is used for fixing the bottom of the upper casing and the top of the lower casing; the back of the connecting clamping piece is provided with a notch into which the hoop piece is inserted.

As a further improvement of the invention, the radial L-shaped fixed slat is also arranged; the fixed lath is L-shaped, one end of the fixed lath is provided with a vertical steel plate, and a steel casing is welded with a steel plate with holes at the top of the fixed lath after being embedded.

As a further improvement of the invention, the lower parts of the vertical rods are connected through springs.

A pile foundation pore-forming steel pile casing construction method comprises the following steps:

s1, construction preparation: leveling a field, clearing sundries, preparing materials required by construction and binding a reinforcement cage;

s2, measurement and positioning: determining a hole site center pile by using a total station and a steel ruler, arranging guide arc plates around the pile site, reinforcing the pile guard by using cement mortar, and establishing an obvious mark;

s3, setting the ultra-long steel casing: installing the pile casing in sections according to the thickness of a soft soil layer on the earth surface, wherein the diameter of each section of steel casing is increased by 20cm compared with the designed pile diameter, and the length of each section is 2 m; preliminarily judging the embedding depth of the steel casing according to geological survey data, calculating the number of sections required by the steel casing, wherein the steel casing is required to enter a field in advance, and the steel casing is embedded and penetrates through a soft soil layer;

s4, embedding a lower steel casing: after the setting position of the lower protective barrel is determined, a guide structure is arranged on the side of the designed position of the protective barrel, the steel protective barrel is placed down by using a crane, one side of the steel protective barrel is placed down along a guide arc plate, the plane position deviation of the steel protective barrel is controlled within 5cm, and the gradient deviation is controlled within 1%;

s5, lowering the rear section of steel casing: a pile casing alignment assembly is arranged in the upper pile casing, an upper arc plate of the pile casing alignment assembly is clamped at the top of the upper pile casing, and the steel pile casing is lowered down, so that the upper pile casing slides down along the guide arc plate to be aligned with the lower pile casing;

s6, welding and installing the connecting outer hoop device: installing semicircular hoops at the bottom of the upper pile casing and the top of the lower pile casing respectively, penetrating the two ends of each semicircular hoop through the connecting clamping pieces to be fastened and then welding, and welding and fixing the upper connecting clamping piece and the lower connecting clamping piece through longitudinal steel sheets after the two pile casings are welded in alignment;

s7, the last section of steel casing: when a section of protection cylinder is embedded, the high ground of the top surface of the protection cylinder is ensured to be 0.3m, and the ground water level at the high position is ensured to be 2 m; welding a steel plate with holes on the top of the pile casing, and fixing the steel pile casing with the soil nails after fixing the L-shaped soil nail fixing strip and the steel pile casing;

s8, positioning a drilling machine: after the percussion drill rig is installed, the center of a drill bit is accurately aligned to the cross center of the casing, the drill bit is lifted and slowly placed into the steel casing, a slurry pump is started, and the percussion is started after a certain amount of slurry is delivered into the hole;

s9, drilling: when the karst stratum is approached, the prepared mud is confirmed to be sufficient before breakdown, and the phenomenon that the mud is suddenly lost after the karst cave is broken down to cause insufficient pressure in the hole to form hole collapse is avoided; the geological inspection and rechecking of the drill hole are enhanced, and the working condition of the drilling machine, the surrounding ground surface settlement and the water level change in the casing are closely observed;

s10, final hole and hole cleaning: cleaning holes by adopting a pulp changing and hole cleaning method; the height of a water head in the hole is ensured to be kept in the hole cleaning process, and hole collapse is prevented;

s11, lowering a reinforcement cage: after hole cleaning is finished, putting down the reinforcement cage, and fixing the top of the reinforcement cage by using a fixing device;

s12, pouring concrete: and concrete pouring is realized by utilizing an automobile pump.

Compared with the prior art, the invention has the beneficial effects that:

this application is through setting up guide structure and protecting a section of thick bamboo alignment subassembly, realizes that the upper and lower steel protects an axial more accurate positioning of section of thick bamboo, and the rethread sets up the outer hoop subassembly and realizes the upper and lower steel and protects a fixed connection of section of thick bamboo, has improved the location installation effectiveness and the installation progress that the steel protected a section of thick bamboo greatly, and design benefit has improved the pile forming efficiency and the quality of forming a pile of pile foundation simultaneously greatly.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a schematic view of the present invention in use;

FIG. 2 is a schematic view of the guide structure of the present invention in use;

FIG. 3 is a partial cross-sectional view of FIG. 1;

FIG. 4 is a schematic view of the construction of the shroud alignment assembly of the present invention;

FIG. 5 is a schematic view of the upper arc plate mounting structure of FIG. 4;

FIG. 6 is a schematic structural view of a connected steel casing according to the present invention;

FIG. 7 is a top view of FIG. 6;

FIG. 8 is a block flow diagram of the present invention;

the reference numbers in the figures illustrate:

1. a guide structure; 11. a guide arc plate; 12. a support frame; 2. a casing alignment assembly; 21. a limiting arc plate structure; 211. An upper arc plate; 212. a lower arc plate; 213. a vertical rod; 214. a spring; 22. a pressure spring; 23. a retractable positioning member; 231. Penetrating a rod; 232. a sleeve; 3. an outer band assembly; 31. an upper band body; 32. a lower band body; 33. longitudinal steel sheets; 4. a steel casing; 41. an upper protective cylinder; 42. a lower protective cylinder; 5. and fixing the lath.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The invention provides a pile foundation pore-forming steel casing construction system and a construction method by combining with attached drawings 1 to 8, aiming at the technical problem of improving the efficiency and the precision of steel casing butt joint.

Specifically, the pile foundation pore-forming steel pile casing construction system comprises a guide structure 1, a pile casing alignment assembly 2 and an outer hoop assembly 3; the guide structure 1 comprises a guide arc plate 11; the guide arc plate 11 is positioned at the outer side of the pile foundation; the inner side wall of the guide arc plate 11 is matched with the outer side wall of the steel casing 4 in size, and is used for limiting and guiding the outer side edge of the steel casing 4;

the pile casing alignment assembly 2 comprises a limiting arc plate structure 21, an elastic piece and a telescopic positioning piece 23; the limiting arc plate structure 21 comprises an upper arc plate 211 and a lower arc plate 212; the upper arc plate 211 is positioned and clamped at the top of the steel casing 4; the lower arc plate 212 is matched with the inner side wall of the steel casing 4 in size; the upper arc plate 211 is fixedly connected with the lower arc plate 212 through a vertical rod 213; the two limiting arc plate structures 21 are oppositely arranged on the steel casing 4; two ends of the elastic piece are respectively connected with the limiting arc plate structure 21; two ends of the telescopic positioning piece 23 respectively penetrate through the vertical rod 213 and extend outwards to be abutted against the limiting arc plate structure 21;

the outer hoop assembly 3 comprises an upper hoop body 31 and a lower hoop body 32; the upper hoop body 31 and the lower hoop body 32 are respectively arranged on the adjacent steel casing 4, and the positioning connection of the upper hoop body 31 and the lower hoop body 32 is realized through a longitudinal steel sheet 33.

This application is through setting up guide structure 1 and protecting a section of thick bamboo alignment subassembly 2, realizes that the upper and lower steel protects an axial more accurate positioning of section of thick bamboo, and the rethread sets up outer hoop assembly 3 and realizes the upper and lower steel and protects a fixed connection of section of thick bamboo, has improved the location installation effectiveness and the installation progress of a steel section of thick bamboo 4 greatly, design benefit has improved the pile forming efficiency and the quality of forming a pile of pile foundation simultaneously greatly.

Further, the guiding structure 1 further comprises a supporting frame 12; the supporting frame is positioned on the foundation at the side edge of the foundation pile; the guide arc plate 11 is positioned on the support frame 12.

Further, the elastic part is a pressure spring 22; the telescopic positioning part 23 comprises a through rod 231 and a sleeve 232; the sleeve 232 is detachably and fixedly connected to the two axial ends of the through rod 231.

Preferably, the sleeve 232 is screwed at both axial ends of the through rod 231, and the telescopic positioning element 23 is extended and retracted by screwing the sleeve 232 on the through rod 231.

Further, the pressure spring 22 is sleeved on the penetrating rod 231, and two axial ends of the pressure spring 22 are respectively abutted against and limited by the inner side of the vertical rod 213.

Further, the penetrating rod 231 is further provided with scale marks along the axial direction, the scale marks are arranged in a central symmetry mode, the sleeves 232 are symmetrically arranged on the penetrating rod 231 through adjusting the connecting depth of the sleeves 232 at the two ends respectively, and the adjustment is convenient and fast.

Further, the outer hoop assembly 3 is used for fixing the bottom of the upper casing 41 and the top of the lower casing 42, and is formed by two semicircular hoop steel casings 4, the ends of the two semicircular hoop steel casings are inserted into connecting clamping pieces and then welded, and the back of each connecting clamping piece is provided with a notch into which a hoop piece is inserted; after the upper and lower casing 42 are butt-jointed and welded, the upper and lower hoops are welded integrally by the longitudinal steel sheets 33.

It should be noted that, when the retractable positioning element 23 is installed, after the sleeve 232 is screwed off from one end of the penetrating rod 231, the penetrating rod 231 sequentially penetrates through the two symmetrically arranged vertical rods 213, and then the screwed sleeve 232 is installed on one end of the penetrating rod 231; when the length of the whole telescopic positioning piece 23 needs to be adjusted, the whole length can be stretched only by screwing the sleeve 232;

when establishing last arc board 211 card on last steel protects a section of thick bamboo 4, pass through two last arc boards 211 relative positioning of spring 214 this moment, come from the last arc board 211 with both sides with steel protects a section of thick bamboo 4 and support two last arc boards 211 closely embedded in steel protects a section of thick bamboo 4 through adjusting poling 231 and sleeve 232, and the location setting of montant 213 lower part fixed connection's lower arc board 212 protects a section of thick bamboo 42 under in, through adjusting sleeve 232 and poling 231's the depth of connection this moment, realize going up arc board 211 fixed connection's montant 213 axial symmetry location setting

After the upper and lower pile casings 42 are aligned and connected, the outer hoop pile casings are respectively connected with the outer hoop device at the bottom of the upper pile casing 41 and the top of the lower pile casing 42 and are welded and clamped by the connecting clamping pieces; and after the upper and lower protective sleeves 42 are welded, the outer hoop device is welded and fixed through the longitudinal steel sheets 33.

A radial L-shaped fixed slat 5 is also arranged; the fixed slat 5 is the L type, and one end is equipped with vertical steel sheet, and foraminiferous steel sheet of welding at its top after the completion is buried underground to steel protects a section of thick bamboo 4, and the bolt hole that passes two steel sheets through the bolt protects a section of thick bamboo 4 with fixed steel, and the fixed slat 5 other end of L type is equipped with soil nail hole, thereby fixes the fixed steel of L type on the ground and protects a section of thick bamboo through squeezing into soil nail with the fixed slat 5 of L type.

Further, the lower part of montant 213 passes through spring 214 to be connected, can realize putting down arc plate 212 in steel protects a section of thick bamboo 4, mainly realizes elastic connection through pressure spring 22 and spring 214 between the upper and lower arc plate 212 of whole retractable setting element, avoids the hard contact with individual part when placing to lead to the damage of part, avoid appearing fixing a position the inaccurate condition and appear, design benefit, practical convenient and flexible.

A pile foundation pore-forming steel pile casing construction method comprises the following steps:

s1, construction preparation: leveling a field, clearing sundries, preparing materials required by construction and binding a reinforcement cage;

s2, measurement and positioning: determining a hole site center pile by using a total station and a steel ruler, arranging guide arc plates 112 around the pile site, reinforcing the pile guard by using cement mortar, and establishing an obvious mark;

s3, setting the ultra-long steel casing 4: installing the pile casing in sections according to the thickness of a soft soil layer on the earth surface, wherein the diameter of each section of steel casing 4 is increased by 20cm compared with the designed pile diameter, and the length of each section is 2 m; preliminarily judging the embedding depth of the steel casing 4 according to geological survey data, calculating the number of sections required by the steel casing 4, advancing the steel casing 4 in advance, and embedding the steel casing 4 to penetrate through a soft soil layer;

s4, burying a lower steel casing 4: after the hitting position of the lower protective barrel 42 is determined, a guide structure 1 is arranged on the side of the designed position of the protective barrel, a crane is used for lowering the steel protective barrel 4, one side of the steel protective barrel 4 is lowered along the guide arc plate 11, the plane position deviation of the steel protective barrel 4 is controlled within 5cm, and the gradient deviation is controlled within 1%;

s5, lowering the rear section steel casing 4: a pile casing alignment assembly 2 is arranged in the upper pile casing 41, an upper arc plate 211 of the pile casing alignment assembly is clamped at the top of the upper pile casing 41, and the steel pile casing 4 is lowered, so that the upper pile casing 41 slides downwards along the guide arc plate 11 to be aligned with the lower pile casing 42;

s6, welding and installing the connecting outer hoop device: installing semicircular hoops at the bottom of the upper pile casing 41 and the top of the lower pile casing 42 respectively, penetrating the two ends of each semicircular hoop through the connecting clamping pieces for fastening and then welding, and welding and fixing the upper and lower connecting clamping pieces through the longitudinal steel sheets 33 after the two pile casings are welded in alignment;

s7, and the last steel casing 4: when a section of protection cylinder is embedded, the high ground of the top surface of the protection cylinder is ensured to be 0.3m, and the ground water level at the high position is ensured to be 2 m; welding a steel plate with holes on the top of the pile casing, fixing the steel pile casing 4 with the L-shaped soil nail fixing strip and the steel pile casing 4, and then installing the soil nail fixing steel pile casing 4;

s8, positioning a drilling machine: after the percussion drill rig is installed, the center of a drill bit is accurately aligned to the cross center of the pile casing, the drill bit is lifted and slowly placed into the steel pile casing 4, a slurry pump is started, and the percussion is started after a certain amount of slurry is delivered into the hole;

s9, drilling: when the karst stratum is approached, the prepared mud is confirmed to be sufficient before breakdown, and the phenomenon that the mud is suddenly lost after the karst cave is broken down to cause insufficient pressure in the hole to form hole collapse is avoided; the geological inspection and rechecking of the drill hole are enhanced, and the working condition of the drilling machine, the surrounding ground surface settlement and the water level change in the casing are closely observed;

s10, final hole and hole cleaning: cleaning holes by adopting a pulp changing and hole cleaning method; the height of a water head in the hole is ensured to be kept in the hole cleaning process, and hole collapse is prevented;

s11, lowering a reinforcement cage: after hole cleaning is finished, putting down the reinforcement cage, and fixing the top of the reinforcement cage by using a fixing device;

s12, pouring concrete: and concrete pouring is realized by utilizing an automobile pump.

It should be noted that the detailed description of the invention is not included in the prior art, or can be directly obtained from the market, and the detailed connection mode can be widely applied in the field or daily life without creative efforts, and the detailed description is not repeated here.

In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the invention and to simplify the description, and are not intended to indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and are therefore not to be considered limiting of the invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In the present invention, unless otherwise expressly stated or limited, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through an intermediate. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.

Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.