Long spiral drill rod with squeezing and discharging functions for CFG (cement fly-ash gravel) pile

Abstract

The invention discloses a long spiral drill rod with an extruding and discharging function for a CFG pile. A plurality of rows of protruding soil extruding structures are fixedly arranged on the upper side of a spiral blade around the axis of the drill rod. In the engineering foundation drilling process of a saturated silt layer and a silty clay layer of the CFG pile, a plurality of rows of soil squeezing structures arranged on the upper sides of the spiral blades are used for preventing soil from moving upwards along the spiral blades, the discharge amount of the soil is reduced, the soil between the spiral blades is stacked and squeezed, free faces of the soil around the pile are reduced or completely eliminated, and the construction quality of the pile is improved. Therefore, the problem that flow plastic saturated silt and silty clay are squeezed into the space which is not filled with the soil body between the spiral blades through the free face and are conveyed to the ground surface along with the spiral blades, and consequently the soil body around the pile is discharged excessively is solved or completely eliminated. Therefore, the purpose of preventing peripheral soil body settlement of the CFG pile in the drilling process of a saturated silt layer and a silty clay layer is achieved; the long spiral drill rod for the CFG pile has the advantages of being simple in structure and low in cost, and the equipment investment and the construction cost are both controlled.

Description

Technical Field

[0001] The invention relates to the technical field of pile-driving machinery, and in particular to a long spiral drill rod for CFG piles with a squeezing and displacing function. Background Art

[0002] CFG piles are cement fly ash gravel piles. The pile body material uses industrial waste fly ash, which can reduce the cost of the project while also being environmentally friendly. At the same time, CFG piles also have the advantages of short construction period and low cost. Therefore, they have very significant economic and social benefits and are widely used in engineering foundation structures. However, when CFG piles are used in foundation construction in saturated silt layers, silty clay layers (such as the engineering geological conditions of the floodplain in Zhengdong New District, Zhengzhou), and engineering geological conditions where there are fine sand layers in the strata (such as the engineering geological conditions of loess-like silty clay, pebble layers, and sub-layer round gravel and fine sand layers formed by the alluvial and flooding of the Upper Quaternary System in Yibin District, Luoyang), problems such as surrounding soil settlement and channeling will occur, which in turn threatens the safety of surrounding buildings and underground pipe networks, thereby limiting the application of CFG piles in engineering foundations in saturated silt layers and silty clay layers. In the article [Experimental Study and Finite Element Analysis of Engineering Environmental Problems Caused by CFG Pile Construction], a relatively detailed study was conducted on this issue, pointing out that the reason for the settlement of the surrounding soil when CFG piles are used in the construction of saturated silt and silty clay foundations is that at different depths of CFG piles with long spiral drill rods, at the same rotation speed, the soil in different soil layers rises at different speeds with the spiral blades, resulting in the lack of soil between the spiral blades, causing an empty surface to appear in the soil around the pile; due to the disturbance of the soil in the saturated silt and silty clay layers by the drill bit and drill rod during the drilling process, the saturated silt and silty clay appear in a liquefied and fluidized state, and the fluidized saturated silt and silty clay squeeze into the space between the spiral blades that is not filled with soil through the air surface, and are transported to the surface with the spiral blades, causing "excessive soil discharge" of the soil around the pile, which in turn causes settlement of the surrounding soil.

[0003] The national invention patent with application number 201910566885.4 discloses a threaded multi-power composite drill tool, a preparation method and a pile, wherein the threaded multi-power composite drill tool includes a lower power drill tool, a middle power drill tool and an upper power drill tool; an external thread structure is provided on the outer side of the central core tube of the upper power drill tool, and the external thread structure is used to act as a spiral blade of the upper power drill tool; the middle power drill tool is composed of a drill tool body with a composite function of extruding and discharging soil, and the middle power drill tool is provided with an internal thread structure on the inner side of the central core tube of its drill tool body, and the internal thread structure and the external thread structure are adapted to form a threaded connection; the middle power drill tool, driven by its power mechanism, can reciprocate up and down / single rotation and extrusion in the soil extrusion area of ​​the pile hole, so that the rotation and discharge of the upper power drill tool can be squeezed and expanded multiple times / single times and consumed, thereby avoiding the problem of "excessive soil discharge".

[0004] However, in the above-mentioned invention patent, the structure of the threaded multi-power composite drill tool is too complicated, and the structure of the supporting drill rig also becomes too complicated due to the need for multiple sets of power mechanisms, which makes the equipment investment and construction costs relatively high. Therefore, it is necessary to improve its structure. On the premise that the existing drill rig structure remains unchanged, a simple drill tool structure is used to achieve the functions of squeezing and discharging soil, and solve the problem of "excessive soil discharge" causing surrounding soil settlement during the drilling of CFG piles in saturated silt layer and silty clay layer engineering foundation, while keeping the cost of existing drill tools and drilling rigs basically unchanged. Summary of the invention

[0005] In order to overcome the shortcomings of the background technology, the present invention aims to provide a long spiral drill rod for CFG piles with a simple structure, low cost and a soil extrusion function, so as to solve the problem of surrounding soil settlement caused by "excessive soil extrusion" during the drilling of CFG piles in saturated silt layer and silty clay layer engineering foundation, while keeping the cost of existing drilling tools and drilling rigs basically unchanged.

[0006] In order to achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a long spiral drill rod for CFG piles with squeezing and discharging function, comprising a drill rod and spiral blades, the drill rod is a hollow structure, and the spiral blades are fixedly arranged on the outer circumference of the drill rod; a plurality of rows of raised squeezing and discharging structures are evenly distributed and fixedly arranged on the upper side of the spiral blades around the axis of the drill rod.

[0007] Furthermore, the soil squeezing structure is arranged along the entire length of the drill pipe.

[0008] Preferably, the soil squeezing structure is arranged within the length range of the lower 1 / 3-2 / 3 of the drill rod.

[0009] Furthermore, in the same row of soil squeezing structures, the distance between two adjacent soil squeezing structures along the axis of the drill pipe is more than three times the pitch of the spiral blade.

[0010] Furthermore, the distance between the top of the soil squeezing structure and the upper spiral blade is 1 / 3-2 / 3 of the spiral blade pitch. Furthermore, two adjacent rows of soil extrusion structures are staggered up and down.

[0011] Furthermore, the soil squeezing structure is a raised soil squeezing cone.

[0012] Preferably, the soil squeezing structure is an elastic soil squeezing plate, which is fixedly connected to the spiral blade; a gap is provided between the elastic soil squeezing plate and the drill rod.

[0013] Furthermore, a soil discharge groove is provided on the spiral blade fixedly arranged on the lower side of the elastic soil squeezing plate.

[0014] Furthermore, a protective support plate is fixedly provided on the pressure side of adjacent elastic soil squeezing plates between the spiral blades.

[0015] Due to the adoption of the technical scheme as described above, the present invention has the following beneficial effects: a long spiral drill rod for CFG piles with a squeezing and discharging function disclosed by the present invention has a plurality of rows of raised squeezing and discharging structures fixedly arranged around the axis of the drill rod on the upper side of the spiral blades; during the drilling of CFG piles on the engineering foundation of a saturated silt layer or a silty clay layer, a plurality of rows of squeezing and discharging structures arranged on the upper side of the spiral blades are used to prevent the soil from moving upward along the spiral blades, thereby reducing the discharge amount of the soil, causing the soil between the spiral blades to accumulate and squeeze, reducing or completely eliminating the free surface of the soil around the pile, thereby reducing or completely avoiding the problem of "excessive soil discharge" of the soil around the pile caused by the plastic saturated silt and silty clay being squeezed into the space between the spiral blades that is not filled with soil through the free surface and being transported to the surface with the spiral blades, thereby achieving the technical effect of preventing the surrounding soil from settling during the drilling of the CFG pile in the saturated silt layer or the silty clay layer; the long spiral drill rod for CFG piles of the present invention has the advantages of simple structure and low cost, so that both equipment investment and construction costs are controlled. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic diagram of the appearance of a long spiral drill rod for CFG piles with a squeezing function according to the first embodiment; Figure 2 This is a schematic diagram of the appearance of the soil squeezing cone of the first embodiment; Figure 3 This is a schematic diagram of the appearance of a long spiral drill rod for CFG piles with a displacement function according to the second embodiment; Figure 4 Schematic diagram B of the appearance of the elastic soil squeezing plate of the second embodiment; Figure 5 This is a schematic diagram of the appearance of a long spiral drill rod for CFG piles with a displacement function according to Embodiment 3; Figure 6 A schematic diagram A of the axial projection of a long spiral drill rod for a CFG pile with a displacement function according to Embodiment 3; Figure 7 Schematic diagram B of the axial projection of a long spiral drill rod for CFG piles with a displacement function according to the third embodiment.

[0017] In the figure: 1. drill rod; 2. spiral blade; 3. soil squeezing cone; 4. elastic soil squeezing board; 4.1. soil squeezing board body; 4.2. soil squeezing board connecting seat; 5. soil discharge chute; 6. elastic soil squeezing board projection shielding area. DETAILED DESCRIPTION

[0018] The present invention can be explained in detail by the following examples, and the purpose of disclosing the present invention is to protect all technical improvements within the scope of the present invention.

[0019] A long spiral drill rod for CFG piles with a squeezing and discharging function comprises a drill rod 1 and a spiral blade 2. The drill rod 1 is a hollow structure, and the spiral blade 2 is fixedly arranged on the outer circumference of the drill rod 1; a plurality of rows of raised squeezing structures are evenly and fixedly arranged on the upper side of the spiral blade 2 around the axis of the drill rod 1; during the CFG pile drilling process on a saturated silt layer or a silty clay layer engineering foundation, a plurality of rows of raised squeezing structures arranged on the upper side of the spiral blade 2 are used to prevent the soil from moving upward along the spiral blade, so that the discharge amount of the soil is reduced, and the soil is piled up and squeezed between adjacent spiral blades 2, thereby reducing or completely eliminating the adjacent spiral blades. The space between the spiral blades 2 that is not filled with soil reduces or eliminates the free surface of the soil on the hole wall, thereby reducing or completely avoiding the problem of "excessive soil discharge" of the soil around the pile caused by the plastic saturated silt and silty clay squeezing into the space between the spiral blades that is not filled with soil through the free surface and being transported to the surface as the spiral blades rotate, thereby achieving the technical effect of preventing the surrounding soil from settling during the drilling process of the CFG pile in the saturated silt layer and silty clay layer; the long spiral drill rod for the CFG pile of the invention has the advantages of simple structure and low cost, which also controls the equipment investment and construction costs.

[0020] Furthermore, the soil squeezing structure is arranged along the entire length of the drill rod 1; the amount of soil discharged during the construction of the drill rod 1 with the soil squeezing structure arranged throughout the entire length is small, and it is suitable for the construction of CFG piles in engineering foundations with loose soil and good soil squeezing properties (such as the engineering geological conditions of the floodplain in Zhengdong New District, Zhengzhou). It can prevent the surrounding soil settlement during the drilling process by reducing "excessive soil discharge", and at the same time improve the compactness of the soil around the pile, increase the side friction resistance of the soil around the pile, and thus improve the bearing capacity of the CFG pile.

[0021] Preferably, the soil squeezing structure is arranged within the length range of 1 / 3-2 / 3 of the lower part of the drill rod 1; the drill rod 1 with only the soil squeezing structure arranged at the lower part of the drill rod 1 has a large amount of soil discharge during construction, and is suitable for CFG pile construction in engineering foundations with hard soil and poor soil squeezing properties, so as to avoid excessive torque of the drill rod during drilling caused by too small a soil discharge amount, thereby reducing the drilling efficiency.

[0022] Furthermore, in the same row of soil squeezing structures, the distance between two adjacent soil squeezing structures along the axis of the drill rod 1 is more than three times the pitch of the spiral blade 2, so as to prevent excessive torque of the drill rod caused by too many soil squeezing structures.

[0023] Furthermore, the distance between the top of the soil squeezing structure and the upper spiral blade 2 is 1 / 3-2 / 3 of the pitch of the spiral blade 2 .

[0024] Furthermore, two adjacent rows of soil squeezing structures are staggered up and down to ensure that the radial force of the long spiral drill rod is balanced in the entire working section when it is working.

[0025] Further, the soil squeezing structure is a soil squeezing cone 3; see the attached Figure 1 ,2 The cross section of the soil squeezing cone 3 is triangular and is fixed on the upper side of the spiral blade 2 by welding. The height of the soil squeezing cone 3 is 1 / 3-2 / 3 of the pitch of the spiral blade, and the specific value can be obtained through on-site test drilling. After obtaining the relevant parameters of the soil squeezing cone 3 through on-site test drilling, the existing long spiral drill rod can be welded and transformed on-site to make the ordinary long spiral drill rod a long spiral drill rod for CFG piles with squeezing function. The soil squeezing cone 3 structure has the advantages of high structural strength, low requirements on material properties, and on-site transformation of ordinary long spiral drill rods, which can reduce the procurement and use costs of long spiral drill rods. The long spiral drill rod with this structure is suitable for CFG pile construction in engineering foundations with loose soil and good soil squeezing properties (such as the engineering geological conditions of the floodplain in Zhengdong New District, Zhengzhou).

[0026] See the instruction manual Figure 3 , 4 : Preferably, the soil squeezing structure is an elastic soil squeezing plate 4, which is fixedly connected to the spiral blade 2 by welding or bolts (the bolt connection is a detachable connection, and the damaged elastic soil squeezing plate 4 can be replaced); when not working, the distance between the top of the elastic soil squeezing plate 4 and the upper spiral blade 2 is 1 / 3-2 / 3 of the spiral blade pitch; a gap is provided between the elastic soil squeezing plate 4 and the drill rod 1, and the gap separates the elastic soil squeezing plate 4 from the drill rod 1, so that the elastic soil squeezing plate 4 will move downward when the upper side of the elastic soil squeezing plate 4 is squeezed by the soil The elastic deformation increases the distance between the top of the elastic soil squeezing plate 4 and the upper spiral blade 2, allowing more soil to pass over the elastic soil squeezing plate 4 and be discharged; and the size of the soil squeezing force on the upper side of the elastic soil squeezing plate 4 is related to the extrudability of the soil in different engineering strata at the construction site, that is, when the extrudability of the soil in the stratum is high (the soil is loose and has a high porosity), the smaller the pressure between the spiral blades 2 acting on the upper side of the elastic soil squeezing plate 4, the smaller the soil that passes over the elastic soil squeezing plate 4 and is discharged. When the compressibility of the soil in the stratum is low (the soil is dense and has a low porosity), the greater the pressure of the soil entering between the spiral blades 2 on the upper side of the elastic soil squeezing plate 4, the more soil will be discharged over the elastic soil squeezing plate 4; therefore, during the drilling process, the long spiral drill rod with this elastic soil squeezing plate 4 structure can automatically change the amount of soil discharge according to the different compressibility of the soil in different strata of the construction site, which can avoid the settlement of the soil around the borehole caused by "excessive soil discharge" and avoid Avoid the problem of excessive torque of the drill rod caused by too small soil discharge volume; in addition, when the long spiral drill rod with elastic soil squeezing plate 4 is used in pebble strata (such as the engineering geological conditions of loess-like silty clay, pebble layers and sub-layer round gravel and fine sand layers formed by the alluvial and flood action of the Quaternary System in Yibin District, Luoyang), it can avoid the problem of the pebble diameter being too large to pass through the elastic soil squeezing plate 4, causing the drill to get stuck and the soil to be unable to be discharged. Therefore, it can automatically adapt to the technical effect of CFG pile construction under complex geological conditions and has a wider adaptability.

[0027] See the instruction manual Figure 5 : Further, a soil discharge groove 5 is provided on the spiral blade 2 connected to the lower part of the elastic soil squeezing plate 4; the purpose of setting the soil discharge groove 5 is to prevent the elastic soil squeezing plate 4 from being elastically deformed when the elastic soil squeezing plate 4 is squeezed by the soil on its upper side when soil is accumulated between the elastic soil squeezing plate 4 and its lower spiral blade 2; in addition, when the soil squeezing force on the elastic soil squeezing plate 4 is small, the elastic deformation of the elastic soil squeezing plate 4 is also small, and the projection of the elastic soil squeezing plate 4 along the axis of the long spiral drill rod falls within the range of the soil discharge groove 5 at its lower part (see the attached manual Figure 6 ), at this time, most of the soil will pass over the elastic soil squeezing plate 4 and fall into the soil discharge groove 5 at the bottom of the elastic soil squeezing plate 4, and then enter the next layer of spiral blades 2 through the soil discharge groove 5, thereby reducing the amount of soil discharge (the reduction in the amount of soil discharge means the increase in the amount of soil squeezed); the soil entering between the next layer of spiral blades 2 will be squeezed again, and within a shorter drilling depth, the space between the spiral blades 2 will be filled with soil to reduce or eliminate the free surface, thereby avoiding "excessive soil discharge" of the saturated silt layer and silty clay layer due to the existence of the free surface when the drill rod enters the saturated silt layer and silty clay layer; as the drilling depth increases, the soil between the spiral blades 2 is blocked and squeezed by the elastic soil squeezing plate 4, and the soil squeezing pressure acting on the upper side of the elastic soil squeezing plate 4 naturally increases, causing the elastic soil squeezing plate 4 to deform significantly. At this time, the projection of the elastic soil squeezing plate 4 along the axis of the long spiral drill rod passes over the soil discharge groove 5 at its bottom, forming a spiral blade 2 projection shielding area on the spiral blade 2 (see the attached diagram of the manual Figure 7 ), so the amount of soil that passes over the elastic soil squeezing plate 4 and falls on the spiral blades 2 on the lower side of the elastic soil squeezing plate 4 increases (increased soil discharge), and only a small amount (or even no) of soil falls between the next layer of spiral blades 2 through the soil discharge groove 5, thereby adaptively achieving a balance between soil discharge and soil squeezing during the drilling process, which not only avoids the technical effect of surrounding soil settlement caused by "excessive soil discharge" but also prevents the problem of excessive drill rod torque caused by too small a soil discharge amount.

[0028] Furthermore, a protective support plate (not shown in the figure) is provided on the pressure side of the adjacent elastic soil squeezing plates 4 between the spiral blades 2, which is used to support and protect the elastic soil squeezing plates 4 when the long spiral drill rod rotates in the reverse direction, and to prevent the elastic soil squeezing plates 4 from being damaged due to excessive reverse deformation when the long spiral drill rod rotates in the reverse direction.

[0029] Example 1, see the attached specification Figure 1 , 2 : A long spiral drill rod for CFG piles with a squeezing function comprises a drill rod 1 and a spiral blade 2. The drill rod 1 is a hollow structure, and the spiral blade 2 is fixedly arranged on the outer circumference of the drill rod 1; three rows of squeezing cones 3 are evenly and fixedly arranged around the axis of the drill rod 1 on the upper side of the spiral blade 2; the cross-section of the squeezing cone 3 is a bent steel plate, and is fixedly arranged on the upper side of the spiral blade 2 by welding; the three rows of squeezing cones 3 are arranged along the entire length of the drill rod 1, and the distance between the two squeezing cones 3 closest to each other along the axis of the drill rod 1 is 4 / 3 times the pitch of the spiral blade 2. In the same row of squeezing cones 3, the distance between two adjacent squeezing structures along the axis of the drill rod 1 is 4 times the pitch of the spiral blade 2; the distance between the top of the squeezing cone 3 and the upper spiral blade 2 is 1 / 3 of the pitch of the spiral blade 2; the squeezing cones 3 in two adjacent rows are staggered up and down.

[0030] The working principle of the long spiral drill rod with extrusion function for CFG piles is described in detail below. For the convenience of description and understanding, only the working process of the first soil-extruding cone 3 at the bottom of the drill rod is described below. The soil-extruding function of the long spiral drill rod with three rows of soil-extruding cones 3 can be simply considered as the accumulation of the functions of all the soil-extruding cones 3. During the CFG pile drilling process on the engineering foundation of the saturated silt layer and silty clay layer with the long spiral drill rod with extrusion function, the long spiral drill rod rotates and drills into the soil, and the soil enters between the spiral blades 2 and moves upward along the spiral blades; the soil-extruding cone 3 arranged on the upper side of the spiral blades 2 prevents the soil from moving along the spiral blades The spiral blades 2 move upward, and only when the soil accumulation and extrusion thickness on the spiral blades 2 exceeds the height of the soil-extruding cone 3, the soil will pass over the soil-extruding cone 3 and be discharged, thereby reducing the discharge amount of the soil, and increasing the extrusion amount between adjacent spiral blades 2. As a result, the space between adjacent spiral blades 2 that is not filled with soil is reduced, so that the free surface of the soil on the borehole wall is reduced; when drilling into the fluidized saturated silt and silty clay strata, since the space between adjacent spiral blades 2 that is not filled with soil is reduced, the discharge amount of the fluidized saturated silt and silty clay through the free surface is correspondingly reduced, thereby improving the problem of surrounding soil settlement caused by "excessive soil discharge" around the borehole.

[0031] Example 2, see the attached specification Figure 3 , 4 : In this embodiment, two rows of elastic soil squeezing plates 4 are evenly distributed and fixedly arranged on the upper side of the spiral blade 2 around the axis of the drill rod 1. The elastic soil squeezing plates 4 include a soil squeezing plate body 4.1 and a soil squeezing plate connecting seat 4.2. The material is selected from spring steel with good elasticity, which is formed by bending after being cut to the required shape; the elastic soil squeezing plates 4 are fixedly arranged on the upper side of the spiral blade 2 by welding the soil squeezing plate connecting seat 4.2, or holes are punched on the soil squeezing plate connecting seat 4.2 and the spiral blade 2, and the soil squeezing plate connecting seat 4.2 is detachably arranged on the upper side of the spiral blade 2 by bolts; a gap is provided between the soil plate body 4.1 and the adjacent surface of the drill rod 1; the two rows of elastic soil squeezing plates 4 are arranged at the lower 2 / 3 of the drill rod 1 Within the length range, the distance between the two elastic soil squeezing plates 4 closest to each other along the axis of the drill rod 1 is 1.5 times the pitch of the spiral blade 2. In the same row of elastic soil squeezing plates 4, the distance between two adjacent soil squeezing structures along the axis of the drill rod 1 is 3 times the pitch of the spiral blade 2; the soil squeezing cones 3 in two adjacent rows are staggered up and down; the distance between the top of the elastic soil squeezing plate 4 and the upper spiral blade 2 is 1 / 3 of the pitch of the spiral blade 2 (smaller than that in Example 1), so when the elastic soil squeezing plate 4 is not deformed, the soil on the spiral blade 2 needs to be squeezed to a thicker thickness when passing over the elastic soil squeezing plate 4. Therefore, when the set soil squeezing requirement is not met, only very little soil is discharged.

[0032] In this embodiment, the function of the elastic soil squeezing plate 4 is basically the same as that of the soil squeezing cone 3. The difference is that after the elastic soil squeezing plate 4 is adopted, the elasticity of the elastic soil squeezing plate 4 can be utilized to automatically change the amount of soil discharge according to the difference in compressibility of soil bodies in different strata of the construction site; In order to facilitate the description and understanding of the functions of the elastic soil squeezing plate 4, only the working process of the first elastic soil squeezing plate 4 at the bottom of the drill rod 1 is described below. The soil squeezing and discharging function of the long spiral drill rod provided with two rows of elastic soil squeezing plates 4 can be simply considered as the accumulation of the functions of all elastic soil squeezing plates 4. When the long spiral drill rod is used to drill CFG piles on the engineering foundation of the saturated silt layer and silty clay layer, the long spiral drill rod rotates and drills into the soil, and the soil enters between the spiral blades 2 and moves upward along the spiral blades; when the soil encounters the elastic squeezing plate 4, it is blocked and cannot continue to move upward along the spiral blades, but with the continuous rotation of the long spiral drill rod, soil continuously enters between the spiral blades 2, so the soil begins to accumulate and squeeze between the starting end of the spiral blade 2 and the first elastic squeezing plate 4. At this time, since the squeezing force of the soil on the elastic squeezing plate 4 is small, the elastic squeezing plate 4 hardly deforms; due to the internal friction angle of the soil, the increase in thickness of the soil on the spiral blade 2 starts from the starting end of the spiral blade 2 and moves toward the elastic squeezing plate 4 in the form of an inclined surface. The soil on the spiral blade 2 is pushed forward, and the soil on the spiral blade 2 is initially squeezed, and the density is improved; when the height of the soil squeezing slope exceeds the height of the elastic squeezing plate 4, some soil passes over the elastic squeezing plate 4 and is discharged. At this time, the squeezing force of the soil on the elastic squeezing plate 4 is gradually increased, and the squeezing force on the soil is also increased, and the soil is squeezed for the second time, and the density is further improved; in the secondary squeezing process of the soil, when the squeezing force of the soil on the elastic squeezing plate 4 is small, the downward bending deformation of the elastic squeezing plate 4 is also small, and the amount of soil discharged over the elastic squeezing plate 4 is also small. When the squeezing force of the soil on the elastic squeezing plate 4 is large, the downward bending deformation of the elastic squeezing plate 4 is also large, and the amount of soil discharged over the elastic squeezing plate 4 is also large, so the discharge amount of the soil is positively correlated with the squeezing force it is subjected to; The amount of soil discharged over the elastic soil squeezing plate 4 is related to the compressibility of the soil in different engineering strata at the construction site, that is, when the compressibility of the soil in the stratum is high (the soil is loose and has a high porosity), the soil entering between the spiral blades 2 needs to be squeezed to a greater extent before a greater squeezing force is generated on the elastic soil squeezing plate 4, so the amount of soil discharged is naturally less; when the compressibility of the soil in the stratum is low (the soil is dense), the soil entering between the spiral blades 2 only needs a smaller squeezing force to generate a greater squeezing force on the elastic soil squeezing plate 4, so the amount of soil discharged is naturally more; therefore, the long spiral drill rod provided with the elastic soil squeezing plate 4 can automatically change the amount of soil discharged according to the different geological conditions of the construction site and the different compressibility of the stratum soil; In addition, when the long spiral drill rod provided with the elastic soil squeezing plate 4 is applied to a pebble stratum (for example, the engineering geological conditions of loess-like silty clay, pebble layer, sub-layer round gravel, and fine sand layer formed by the alluvial action of the upper Quaternary system in Yibin District, Luoyang), the elastic deformation of the elastic soil squeezing plate 4 can be used to solve the problem of the drill being stuck and unable to discharge soil due to the large diameter of the pebble that cannot pass through the soil squeezing cone 3 of the non-elastic deformation structure in the embodiment, thereby having the technical effect of automatically adapting to the construction of CFG piles under complex geological conditions; When the long spiral drill rod of this embodiment is drilling, the space between the spiral blades 2 at the lower end of the long spiral drill rod will be filled with soil first, thereby eliminating the empty surface; when drilling to the saturated silt and silty clay layer, the saturated silt and silty clay are liquefied due to the disturbance of the drill bit, and the internal friction angle of the liquefied silt and silty clay is extremely small, and there is no empty surface in the drill hole. When the drill rod passes through the saturated silt and silty clay layer, it is almost in a squeeze drilling state without producing soil discharge. Therefore, there is no need to reduce the drilling speed when drilling through the saturated silt and silty clay layer, thereby ensuring the high efficiency of CFG pile construction.

[0033] Example 3, see the attached specification Figure 5 : Compared with the second embodiment, in this embodiment, two rows of elastic soil squeezing plates 4 are arranged within the length range of the lower 1 / 3 of the drill rod 1; a soil discharge groove 5 is provided on the spiral blade 2 fixedly arranged at the lower side of the elastic soil squeezing plate 4; the soil discharge groove 5 of this embodiment has two functions: 1. to prevent soil from accumulating between the elastic soil squeezing plate 4 and the spiral blade 2 below it, thereby affecting the elastic deformation of the elastic soil squeezing plate 4 when it is squeezed by the soil on its upper side; 2. to speed up the time for the space between the spiral blades 2 to be filled with soil, so that the drill rod can eliminate the free surface of the hole at a shallow drilling depth, and prevent the problem of "excessive soil discharge" due to the existence of the free surface when the drill rod drills into or passes through the saturated silt and silty clay layer when the burial depth is shallow.

[0034] In order to facilitate the description and understanding of the function of the soil discharge trough 5, only the working process of the first soil discharge trough 5 at the bottom of the drill rod 1 is described below: When the soil body exerts a small squeezing force on the elastic soil squeeze plate 4, the elastic deformation of the elastic soil squeeze plate 4 is also small, see the attached manual. Figure 6 : The projection of the elastic soil squeezing plate 4 along the axis of the long spiral drill rod falls within the range of the soil discharge groove 5 at its lower part. At this time, most of the soil after passing over the elastic soil squeezing plate 4 will fall into the soil discharge groove 5 at the lower part of the elastic soil squeezing plate 4, and then enter between the next layer of spiral blades 2 through the soil discharge groove 5, thereby reducing the amount of soil discharge (the reduction in the amount of soil discharge means the increase in the amount of soil squeezed). The soil entering between the next layer of spiral blades 2 will be squeezed for the third time, and within a shorter drilling depth, the space between the spiral blades 2 will be filled with soil to reduce or eliminate the free surface. Therefore, it is used in the foundation construction of saturated silt layer and silty clay with a shallow burial depth, which can avoid the saturated silt layer and silty clay layer "excessive soil discharge" caused by the existence of the free surface when the drill rod enters the saturated silt layer and silty clay layer; when the elastic deformation of the elastic soil squeezing plate 4 is large, refer to the attached manual Figure 7: The projection of the elastic soil squeezing plate 4 along the axis of the long spiral drill rod falls on the spiral blade 2 on its lower side, completely "covering" the soil discharge groove 5. The soil that passes over the elastic soil squeezing plate 4 falls completely on the spiral blade 2 on the lower side, and no soil will enter the next layer of spiral blades 2 through the soil discharge groove 5, avoiding excessive squeezing of the soil (too small soil discharge volume) and causing excessive torque of the drill rod.

[0035] Embodiment 4: Based on Embodiment 2 or 3, a protective support plate is provided on the pressure side of the adjacent elastic soil squeezing plates 4 between the spiral blades 2, which is used to support and protect the elastic soil squeezing plates 4 when the long spiral drill rod rotates in the reverse direction, and to prevent the elastic soil squeezing plates 4 from being damaged due to excessive reverse deformation when the long spiral drill rod rotates in the reverse direction.

[0036] The parts not described in detail in this invention are prior art.

[0037] Those skilled in the art should understand that they can implement variations by combining the prior art and the above embodiments. Such variations do not affect the essence of the present solution and are not described in detail here.

[0038] It should be understood that the present solution is not limited to the above-mentioned specific implementation methods, and the devices and structures that are not described in detail should be understood to be implemented in a common manner in the art; any technician familiar with the art can make many possible changes and modifications to the technical solution of the present solution by using the above-mentioned disclosed structures and technical contents without departing from the scope of the technical solution of the present solution, or modify it into an equivalent embodiment with equivalent changes, which does not affect the essential content of the present solution. Therefore, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present solution without departing from the content of the technical solution of the present solution still falls within the scope of protection of the technical solution of the present solution.

Claims

1. A long spiral drill rod for CFG piles with a displacement function, comprising a drill rod (1) and a spiral blade (2), wherein the drill rod (1) is a hollow structure and the spiral blade (2) is fixedly arranged on the outer circumference of the drill rod (1); wherein: A plurality of rows of soil squeezing structures are evenly and fixedly arranged on the upper side of the spiral blade (2) around the axis of the drill rod (1).

2. The long spiral drill rod for CFG piles with a displacement function according to claim 1 is characterized by: The soil squeezing structure is arranged along the entire length of the drill rod (1).

3. The long spiral drill rod for CFG piles with a displacement function according to claim 1 is characterized by: The soil squeezing structure is arranged within the length range of 1 / 3 to 2 / 3 of the lower part of the drill rod (1).

4. The long spiral drill rod for CFG piles with a displacement function according to claim 1 is characterized by: In the same row of soil squeezing structures, the distance between two adjacent soil squeezing structures along the axis of the drill rod (1) is more than three times the pitch of the spiral blade (2).

5. The long spiral drill rod for CFG piles with the function of squeezing and displacing according to claim 1 is characterized by: The distance between the top of the soil squeezing structure and the upper spiral blade (2) is 1 / 3-2 / 3 of the pitch of the spiral blade (2).

6. The long spiral drill rod for CFG piles with a displacement function according to claim 1 is characterized by: Two adjacent rows of soil-extrusion structures are staggered up and down.

7. The long spiral drill rod for CFG piles with the function of squeezing and displacing according to claim 1 is characterized by: The soil squeezing structure is a soil squeezing cone (3) which is fixedly connected to the spiral blade (2).

8. The long spiral drill rod for CFG piles with the function of squeezing and displacing according to claim 1 is characterized by: The soil squeezing structure is an elastic soil squeezing plate (4) which is fixedly or detachably connected to the spiral blade (2); a gap is provided between the elastic soil squeezing plate (4) and the drill rod (1).

9. The long spiral drill rod for CFG piles with the function of squeezing and displacing according to claim 8 is characterized by: A soil discharge groove (5) is provided on the spiral blade (2) fixedly arranged on the lower side of the elastic soil squeezing plate (4).

10. The long spiral drill rod for CFG piles with the function of squeezing and displacing according to claims 8 and 9 is characterized in that: A protective support plate is fixedly provided on the pressure-bearing side of the adjacent elastic soil-squeezing plates (4) between the spiral blades (2).

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