CN115897588A

CN115897588A - Construction method of novel rotary-spraying expanded-body anchor rod or anchor cable

Info

Publication number: CN115897588A
Application number: CN202310221525.7A
Authority: CN
Inventors: 吴旭君; 曹文昭; 谌越; 张兴杰; 于至海
Original assignee: Central Research Institute of Building and Construction Co Ltd MCC Group; China Jingye Engineering Corp Ltd
Current assignee: Central Research Institute of Building and Construction Co Ltd MCC Group; China Jingye Engineering Corp Ltd
Priority date: 2023-03-09
Filing date: 2023-03-09
Publication date: 2023-04-04
Anticipated expiration: 2043-03-09
Also published as: CN116289947A; CN115897588B

Abstract

The invention provides a construction method of a novel rotary-spraying expanded-body anchor rod or anchor cable, which comprises the following steps: obliquely driving the sleeve into the soil body to a set depth along the side wall of the foundation pit or the side slope; placing a rotary spraying drill rod into the casing from the top end of the casing, and continuously drilling after the bottom end of the rotary spraying drill rod extends out of the bottom end of the casing until the set bottom position of the expansion head is reached; the part of the rotary spraying drill rod in the sleeve is sleeved with a positioner for preventing the rotary spraying drill rod from being biased; according to the invention, the expansion body is formed by a traditional rotary spraying mode, and the construction process and the grouting sequence are optimized by combining a casing drilling process, so that not only can the anchor rod body and the rotary spraying expansion head effectively form an integral structure, but also the periphery of the anchor rod body can be completely wrapped by cement paste, and the problem of poor corrosion resistance of the anchor rod of the rotary spraying expansion head is effectively solved.

Description

Construction method of novel rotary-spraying expanded-body anchor rod or anchor cable

Technical Field

The invention relates to the technical field of geotechnical engineering construction, in particular to a construction method of a novel rotary jet expanded anchor rod or anchor cable.

Background

The anchor rod is an anchoring system which transmits the pulling force to a stable rock stratum or a soil body through a rod body, one end of the rod body is fixed in a soil layer (or rock stratum) in a side slope or a foundation, the other end of the rod body is connected with an engineering building and a structure, and the external force acting on the building and the structure is balanced by utilizing the anchoring force of the soil layer (or rock stratum), so that the stability of the structure is maintained. When the rod body material adopts a steel strand or a high-strength steel wire bundle, the anchor cable is also called. In order to improve the pulling-resistant bearing capacity of the anchor rod in the soil layer, one method is to increase the diameter of the anchor rod locally at the end part of the anchor rod to form an expanded head anchoring section, so that the frictional resistance and the end resistance between the anchoring section and the soil layer are increased.

The biggest difficulty of the end expanded head anchor rod is the site construction of the expanded head anchoring section:

(1) When the jet grouting method is adopted for the construction of the enlarged head, the jet grouting drill rod needs to horizontally and obliquely extend to the bottom of the anchor hole for jet grouting, the self weight of the jet grouting drill rod and the jet nozzle and other factors easily cause the deviation of the forming position of the jet grouting expanded body, and even the subsequent anchor rod can not be inserted into the jet grouting expanded body in serious conditions;

(2) The jet grouting expansion body is actually cement soil formed by cutting and mixing cement slurry, water and an in-situ soil body, and the cement soil expansion body is formed after curing for a certain time. Different from the traditional equal-section anchor rod, the hole cleaning can be carried out after the drilling is finished so as to ensure the grouting quality, when the jet grouting enlarged head of the end part enlarged head anchor rod is just constructed, the hole cleaning can not be carried out in the anchor hole, otherwise, the clear water used for cleaning the hole can dilute the cement soil at the enlarged head, the construction quality of the enlarged head can be reduced, and the hole collapse at the enlarged head can be easily caused.

Meanwhile, the anchor rod body can have good corrosion resistance only when being completely wrapped by cement paste, the anchor rod body is inserted into the anchor hole under the condition that the hole is not cleaned, the anchor rod body cannot be completely wrapped by the cement paste, and the part of the anchor rod body is wrapped by cement soil or mixed with mud blocks, so that the anchor rod body generates local corrosion, and the long-term use safety of the anchor rod body is seriously weakened.

Disclosure of Invention

The invention aims to provide a construction method of a novel rotary spraying expanded anchor rod or anchor cable, which aims to solve at least one technical problem in the prior art.

In order to solve the technical problem, the invention provides a construction method of a novel rotary spraying expanding body anchor rod or anchor cable, which comprises the following steps:

s10, obliquely driving the sleeve into the soil body along the side wall of the foundation pit or the side slope to a set depth;

s20, placing a rotary spraying drill rod into the rotary spraying drill rod from the top end of the casing, and continuing drilling after the bottom end of the rotary spraying drill rod extends out of the bottom end of the casing until the bottom of the rotary spraying drill rod is set;

the part of the rotary spraying drill rod in the sleeve is sleeved with a positioner for preventing the rotary spraying drill rod from being biased;

s30, injecting clean water and pure cement slurry into a soil body while rotating through a rotary spray head at the bottom end of a rotary spray drill rod, cutting the surrounding soil body by the clean water and the pure cement slurry, and mixing the clean water and the pure cement slurry with the soil body which is cut loosely to form cement soil;

gradually pumping back the rotary spraying drill rod in the rotary spraying grouting process until the rotary spray head retreats into the sleeve; cement soil forms a rotary spraying expanding body (the expanded head is formed after solidification) with the diameter larger than that of the sleeve at the bottom of the sleeve;

then the rotary spraying drill rod is pulled out from the sleeve;

s40, placing the grouting pipe from the top end of the sleeve to the bottom end of the sleeve (namely the top of the expanded head); then injecting pure cement slurry into the sleeve through the grouting pipe until the slurry in the sleeve is completely replaced by the pure cement slurry;

s50, continuing drilling the sleeve until the bottom end of the sleeve extends into the bottom of the rotary spraying expansion body; in the drilling process, the grouting pipe moves synchronously with the casing pipe, and pure cement slurry is continuously injected into the casing pipe through the grouting pipe;

s60, placing the anchor rod or the anchor cable into the sleeve until the bottom end of the anchor rod or the anchor cable extends into the bottom of the jet grouting expanding body;

s70, gradually pulling out the sleeve, and simultaneously injecting pure cement slurry through the grouting pipe to ensure that the anchor rod or the anchor cable is completely wrapped by the pure cement slurry.

Further, the method also comprises the following steps:

and S80, after the sleeve is pulled out for 3 to 4 hours, secondary splitting grouting is carried out through a grouting pipe.

Further, the anchor rod is a bag type anchor rod; step S70, injecting pure cement slurry to the outside of the bag through the grouting pipe while pulling the sleeve;

after the sleeve is pulled out, pure cement slurry is injected into the bag immediately to fill the bag.

Further, the anchor rod is a bag type anchor rod; in step S80, after the sleeve is pulled out for 3 to 4 hours, secondary splitting grouting is carried out through the grouting pipe, and meanwhile, pressure grouting is carried out in the bag.

Further, in step S10, the casing is driven into the soil body in an inclined manner by using a mud drilling method.

Further, the specification of the sleeve is phi 146 x 8mm.

Furthermore, the rotary spraying drill rod is a drill rod with the diameter of 75 mm multiplied by 5 mm.

Further, the water cement ratio of the pure cement paste is 0.6 to 0.8.

Further, the length of the sac is not larger than that of the jet-grouting expansion body, and the diameter of the sac is larger than the outer diameter of the sleeve.

Further, in step S20, a plurality of the locators are sleeved on the portion, inside the casing, of the jet grouting drill pipe at intervals.

The locator is an annular body, a middle through hole of the annular body is matched with the outer diameter of the rotary spraying drill rod, and the outer diameter of the annular body is matched with the inner diameter of the sleeve.

By adopting the technical scheme, the invention has the following beneficial effects:

the construction method of the novel rotary spraying expanded anchor rod or the anchor cable provided by the invention has the following advantages and beneficial effects:

1. the invention adopts a casing drilling process, and the casing can effectively protect the hole wall of the anchor hole during hole forming and prevent hole collapse.

2. The rotary spraying drill rod is provided with the locators at intervals, and the axial position of the rotary spraying drill rod is limited by the sleeve with high rigidity, so that the rotary spraying head can form an expanded head at a designed position through accurate rotary spraying.

3. After the construction of the rotary-spraying expanding body is completed, pure cement slurry is injected into the casing pipe, and the slurry in the casing pipe is completely replaced, so that cement soil at the rotary-spraying expanding body (namely the expanding head) can not be diluted by the slurry in the casing pipe when a subsequent casing pipe is drilled to the expanding head. Meanwhile, when the anchor rod is inserted into the sleeve subsequently, the periphery of the anchor rod is completely wrapped by the pure cement slurry, so that the anchor rod body and the rotary spraying expansion body can be integrated, and the corrosion resistance of the anchor rod can be effectively guaranteed.

4. After the enlarged head is formed, the sleeve continues to be drilled, the conventional diameter section and the enlarged head section of the anchor hole can be effectively connected into a whole, slurry supplementing and secondary splitting grouting are carried out after the sleeve is pulled out, a good common stress system can be formed among the rotary spraying enlarged body, pure cement slurry and the anchor rod body, and the anti-pulling capacity of the anchor rod (cable) is effectively improved.

In a word, the expansion body is formed by the traditional rotary spraying mode, the sleeve drilling process is combined, and the construction process and the grouting sequence are optimized, so that the anchor rod body and the rotary spraying expansion head can effectively form an integral structure, the periphery of the anchor rod body can be completely wrapped by pure cement slurry, and the problem of poor corrosion resistance of the rotary spraying expansion head anchor rod is effectively solved.

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, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.

Fig. 1a is a schematic diagram of step S10 in a construction method of a novel jet grouting expanded anchor rod or anchor cable provided in embodiment 1 of the present invention;

FIG. 1b is a schematic diagram of step S20 in the construction method provided in embodiment 1;

FIG. 1c is a schematic view of step S30 in the construction method according to embodiment 1;

FIG. 1d is a schematic structural diagram illustrating a grouting pipe inserted into a casing pipe in step S40 of the construction method according to embodiment 1;

FIG. 1e is a schematic structural view showing the construction method provided in example 1 in which the slurry in the casing is completely replaced with pure water slurry in step S40;

FIG. 1f is a schematic diagram of step S50 in the construction method according to embodiment 1;

fig. 1g is a schematic structural diagram illustrating that a bolt or an anchor cable is inserted into a casing in step S70 of the construction method provided in embodiment 1;

fig. 2 is a schematic structural view of a balloon anchor rod inserted into a sleeve in the construction method provided in embodiment 1;

FIG. 3 is a schematic structural diagram of a rotary jetting expansion body offset caused by offset of a rotary jetting drill rod and a rotary jetting head due to self weight in the prior art;

FIG. 4 is a schematic view of a layout structure of the first jet grouting enlarged body in embodiment 2;

FIG. 5 is a schematic view of a layout structure of a second jet grouting enlarged body in embodiment 2;

fig. 6 is a schematic diagram of the layout structure of the anchors in embodiment 2.

Reference numerals:

10-a sleeve; 11-grouting pipe; 20-rotary spraying and expanding; 21-a first jet grouting expanded body; 22-a second jet grouting expanded body; 30-jet grouting a drill rod; 31-a rotary sprayer; 40-a locator; 50-anchor rod; 51-a pouch; 60-an anchor member; 61-an anchor rod portion; 62-anchor cable part.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it should be understood that the described embodiments are some, but not all embodiments of the present invention. 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.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in a specific case to those of ordinary skill in the art.

The present invention will be further explained with reference to specific embodiments.

Example 1

The construction method of the novel jet grouting expanded anchor rod or anchor cable provided by the embodiment specifically comprises the following steps:

s10, as shown in a figure 1a, adopting a slurry drilling mode, and obliquely driving the casing 10 into the soil body along the side wall of the foundation pit or the side slope to a set depth;

the gauge of the cannula 10 is preferably 146 x 8mm.

S20, as shown in the figure 1b, placing the rotary spraying drill rod 30 into the casing 10 from the top end, and continuing to drill after the bottom end of the rotary spraying drill rod 30 extends out of the bottom end of the casing 10 until the set bottom position of the expansion head is reached;

the part of the rotary spraying drill rod 30 in the casing 10 is sleeved with a positioner 40 for preventing the rotary spraying drill rod 30 from being biased;

wherein preferably, a plurality of said locators 40 are sleeved on the part of said jet grouting drill pipe 30 in the casing 10 at intervals. The locator 40 is an annular body, the middle through hole of the annular body is matched with the outer diameter of the rotary spraying drill rod 30, and the outer diameter of the annular body is matched with the inner diameter of the sleeve 10.

The jet grouting drill pipe 30 is a drill pipe with the diameter of 75 mm and the diameter of 5 mm.

S30, as shown in figure 1c, injecting clean water and pure cement slurry into the soil body while rotating through a rotary nozzle 31 at the bottom end of a rotary spraying drill rod 30, cutting the surrounding soil body by the clean water and the pure cement slurry, and mixing the clean water and the pure cement slurry with the falling soil body to form cement soil;

gradually pumping back the rotary spraying drill rod 30 in the rotary spraying grouting process until the rotary spray head 31 retreats into the sleeve 10; the cement soil forms a rotary spraying expansion body 20 (forming the expanded head after solidification) with the diameter larger than that of the sleeve 10 at the bottom of the sleeve 10;

then the rotary spraying drill rod 30 is pulled out from the casing 10;

the water-cement ratio of the pure cement slurry is 0.6 to 0.8.

S40, as shown in figure 1d, placing the grouting pipe 11 from the top end of the sleeve 10 to the bottom end of the sleeve 10 (namely the top of the enlarged head); as shown in fig. 1e, pure cement slurry is injected into the casing 10 through the injection pipe 11 until all the soil slurry in the casing 10 is replaced with pure cement slurry; the water-cement ratio of the pure cement slurry is 0.6 to 0.8.

S50, as shown in the figure 1f, continuing drilling the casing 10 until the bottom end of the casing 10 extends into the bottom of the jet grouting expanding body 20; in the drilling process, the grouting pipe 11 moves synchronously with the casing pipe 10, and pure cement slurry is continuously injected into the casing pipe 10 through the grouting pipe 11;

s60, placing the anchor rod 50 or the anchor cable into the sleeve 10 until the bottom end of the anchor rod 50 or the anchor cable extends into the bottom of the jet grouting expanding body 20;

s70, as shown in FIG. 1g, the casing 10 is gradually pulled out, and pure grout is injected through the grout pipe 11, so as to ensure that the anchor rod 50 or the anchor cable is completely wrapped by the pure grout.

Further, the method also comprises the following steps:

and S80, after the sleeve 10 is pulled out for 3 to 4 hours, carrying out secondary split grouting through the grouting pipe 11.

More preferably, referring to fig. 2, the anchor 50 is a balloon anchor; in step S70, while the sleeve 10 is pulled out, pure cement slurry is injected into the outside of the bladder 51 through the grout pipe 11; immediately after the cannula 10 is pulled out, pure cement paste is injected into the bladder 51 to fill the bladder 51. In step S80, after the sleeve 10 is pulled out for 3 to 4 hours, secondary split grouting is performed through the grouting pipe 11, and pressure grouting is performed into the bag 51.

The length of the sac 51 is not greater than the length of the jet-expanding body 20, and the diameter of the sac 51 is greater than the outer diameter of the sleeve 10.

The construction method of the novel rotary spraying expansion body 20 anchor rod 50 or anchor cable provided by the invention has the following advantages and beneficial effects:

1. the invention effectively solves the problem of hole collapse in the construction process of the anchor rod 50. In some bad soil layers containing sand layers, broken stones and the like, hole collapse easily occurs in the construction process of the anchor rod with the enlarged head, and the rod body of the anchor rod 50 cannot be smoothly inserted into the anchor hole, so that the construction of the anchor rod 50 cannot be continued. According to the invention, the casing 10 drilling process is adopted, so that the casing 10 can effectively protect the hole wall of the anchor hole during hole forming, and hole collapse is prevented.

2. As shown in fig. 3, in the prior art, when the anchor rod 50 extension body section performs the spin-spraying operation, when the spin-spraying drill rod 30 horizontally and obliquely extends to the bottom of the anchor hole to perform the spin-spraying operation, the horizontal direction often cannot be accurately located at the center of the anchor hole due to the dead weight of the spin-spraying drill rod 30 and the spin-spraying head 31, so that the formed spin-spraying extension body 20 is severely deviated, and even the anchor rod 50 cannot be inserted into the extension body, thereby greatly reducing the quality of the anchor rod 50.

According to the jet grouting device, the positioning devices 40 are arranged on the jet grouting drill rod 30 at intervals, the axial position of the jet grouting drill rod 30 is limited by the sleeve 10 with high rigidity, and the jet grouting head 31 can be formed into an expanded head at a designed position through accurate jet grouting.

3. In the prior art, holes cannot be cleaned in the construction process of the anchor rod of the enlarged head, otherwise, cement soil at the expanded part is diluted, so that the construction quality of the enlarged head is reduced, and hole collapse at the enlarged head is easily caused. If the grouting is directly carried out without cleaning the hole, the cement slurry injected cannot completely replace the cement soil around the rod body because the specific gravity of the cement soil is equal to that of the pure cement slurry, so that the local part around the rod body is wrapped by the cement soil slurry, even mud blocks and the like generated in the process of the rotating spraying construction of the expansion body section can be mixed, and the local corrosion of the rod body can be generated.

After the construction of the jet grouting expansion body 20 is completed, pure cement slurry is injected into the casing 10, and the slurry in the casing 10 is completely replaced, so that cement soil at the jet grouting expansion body 20 (namely, an expansion head) can not be diluted by the slurry in the casing 10 when the subsequent casing 10 is drilled to the expansion head. Meanwhile, when the anchor rod 50 is inserted into the casing 10 subsequently, the anchor rod 50 is completely wrapped by cement paste, so that the rod body of the anchor rod 50 and the rotary jet expanding body 20 are integrated, and the corrosion resistance of the anchor rod 50 can be effectively guaranteed.

4. After the enlarged head is formed, the sleeve 10 is continuously drilled, the conventional diameter section and the enlarged head section of the anchor hole can be effectively connected into a whole, and slurry supplementing and secondary splitting grouting are carried out after the sleeve 10 is pulled out, so that a good common stress system can be formed among the rotary jet enlarged body 20, pure cement slurry and the anchor rod 50, and the pulling resistance of the anchor rod 50 (or an anchor cable) is effectively improved.

In a word, the expansion body is formed by the traditional rotary spraying mode, and the construction process and the grouting sequence are optimized by combining the drilling process of the sleeve 10, so that the anchor rod 50 and the rotary spraying expansion head can effectively form an integral structure, the periphery of the anchor rod 50 can be completely wrapped by pure cement slurry, and the problem of poor corrosion resistance of the rotary spraying expansion head anchor rod 50 is effectively solved.

Example 2

The construction method of the novel jet grouting expanded anchor rod or anchor cable provided by the embodiment is basically the same as that of the embodiment 1, and the difference is that the construction method specifically comprises the following steps:

s20, as shown in the figure 4, the rotary spraying drill rod 30 is placed into the casing 10 from the top end, and the bottom end of the rotary spraying drill rod 30 extends out of the bottom end of the casing 10 and then continues to drill and exceeds the set bottom position of the expansion head; the part of the rotary spraying drill rod 30 in the casing 10 is sleeved with a positioner 40 for preventing the rotary spraying drill rod 30 from being biased;

injecting pure cement slurry into the soil body while rotating through a rotary nozzle 31 at the bottom end of a rotary spraying drill rod 30, cutting the surrounding soil body by the pure cement slurry, and mixing the pure cement slurry with the falling soil body to form cement soil; gradually pumping back the rotary spraying drill rod 30 in the rotary spraying grouting process, and further forming a first rotary spraying expansion body 21 below the set expansion head in an inclined mode;

s30. After the first jet grouting expanding body 21 is solidified, injecting pure cement slurry into the soil body through the jet nozzle 31 at the bottom end of the jet grouting drill rod 30, gradually pumping the jet grouting drill rod 30 back in the jet grouting process, and forming a second jet grouting expanding body 22 by cement soil at the top of the first jet grouting expanding body 21 and obliquely below the set expanding head;

s40, injecting pure cement slurry into the soil body through the rotary nozzle 31, and forming a rotary spraying expansion body 20 (forming the expansion head after solidification) with the diameter larger than that of the sleeve 10 at the bottom of the sleeve 10; the rotary spraying expansion body 20 and the second rotary spraying expansion body 22 are arranged at intervals or not;

then the rotary spraying drill rod 30 is pulled out from the casing 10;

s50, placing the grouting pipe 11 from the top end of the sleeve 10 to the bottom end of the sleeve 10 (namely the top of the enlarged head); then pure cement slurry is injected into the sleeve 10 through the grouting pipe 11 until all the soil slurry in the sleeve 10 is replaced by the pure cement slurry;

s60, continuing to drill the casing pipe 10 until the bottom end of the casing pipe 10 penetrates through the rotary spraying expansion body 20 to the bottom of the second rotary spraying expansion body 22; in the drilling process, the grouting pipe 11 moves synchronously with the casing pipe 10, and pure cement slurry is continuously injected into the casing pipe 10 through the grouting pipe 11;

s80, as shown in FIG. 6, the anchoring element 60 is placed into the casing 10 from the top, wherein the anchoring element 60 comprises an anchoring rod part 61 and an anchoring cable part 62; the anchor cable part 62 is made of a flexible steel strand; by squeezing the two ends of the anchor cable part 62, the anchor cable part 62 can be forced to bend;

the bottom end of the anchor cable part 62 passes through the second jet grouting expanding body 22 and then abuts against the top of the first jet grouting expanding body 21; then, the anchor cable part 62 is continuously sent downwards; the middle-lower part of the anchor rope part 62 is forced to be coiled in the second rotary spraying expanding body 22 through the anchor rod part 61, the first rotary spraying expanding body 21 and the sleeve 10;

the bottom end of the anchor cable part 62 extends into the bottom of the jet grouting expanding body 20 and is fixedly connected with the top end of the anchor cable part 62 extending out of the top of the second jet grouting expanding body 22;

s90, the sleeve 10 is gradually pulled out, and simultaneously, pure cement slurry is injected through the grouting pipe 11, so that the parts of the anchor rod part 61 and the anchor cable part 62 outside the second rotary jetting expanding body 22 are completely wrapped by the pure cement slurry.

And S100, after the sleeve 10 is pulled out for 3 to 4 hours, carrying out secondary split grouting through the grouting pipe 11.

In order to ensure that the flexible cable wire portion 62 can be smoothly inserted into the bottom of the casing 10, an auxiliary rod may be used for traction, for example, the free end of the cable wire portion 62 is fixed at the bottom end of the grouting pipe 11, so that the cable wire portion 62 extends into the bottom of the casing 10 along with the grouting pipe 11. When the two ends of the anchor cable part 62 are respectively extruded by the anchor rod part 61 and the first jet grouting expanding body 21, the sleeve 10 plays a limiting role at the same time, so that the anchor cable part 62 is forced to be coiled in the sleeve 10; preferably, the casing 10 is gradually pulled out in a semi-solidified state of the grout, and the semi-solidified grout can shape and restrict the anchor cable portion 62.

Compared with the embodiment 1, the embodiment forms a limit table which can be abutted by the preset first jet grouting expansion body 21, so that the anchor cable part 62 which is continuously put in is forced to be gradually coiled and distributed in the second jet grouting expansion body 22, and after the second jet grouting expansion body 22 is solidified, the bonding force between the anchor cable part 62 and the second jet grouting expansion body 22 is stronger and is not easy to separate; when the jet-grouting expansion body 20 and the second jet-grouting expansion body 22 are arranged at a non-interval, i.e. are abutted against each other, the second jet-grouting expansion body 22 abuts against the bottom surface of the jet-grouting expansion body 20, and the anchoring force of the anchoring part 61 is further increased.

When the rotary-spraying expansion body 20 and the second rotary-spraying expansion body 22 are arranged at an interval, the second rotary-spraying expansion body 22 is often arranged at a certain included angle with the rotary-spraying expansion body 20 because of the above-mentioned problem of falling or offset in the prior art, and this structure can also increase the anchoring force between the anchoring part 61 and the rotary-spraying expansion body 20.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and these modifications or substitutions do not depart from the spirit of the corresponding technical solutions of the embodiments of the present invention.

Claims

1. A construction method of a novel rotary spraying expanded anchor rod or anchor cable is characterized by comprising the following steps:

gradually pumping back the rotary spraying drill rod in the rotary spraying grouting process until the rotary spray head retreats into the sleeve; the cement soil forms a rotary spraying expanding body with the diameter larger than that of the casing pipe at the bottom of the casing pipe;

then the rotary spraying drill rod is pulled out from the sleeve;

s40, placing the grouting pipe from the top end of the sleeve to the bottom end of the sleeve; then injecting pure cement slurry into the sleeve through the grouting pipe until the slurry in the sleeve is completely replaced by the pure cement slurry;

s60, placing the anchor rod or the anchor cable into the sleeve until the bottom end of the anchor rod or the anchor cable extends into the bottom of the jet grouting expansion body;

2. The construction method according to claim 1, further comprising the steps of:

3. The construction method according to claim 1, wherein the anchor rod is a bladder type anchor rod; step S70, injecting pure cement slurry to the outside of the bag through the grouting pipe while pulling out the sleeve;

4. The construction method according to claim 1, wherein the anchor rod is a bladder type anchor rod; in step S80, after the sleeve is pulled out for 3 to 4 hours, secondary splitting grouting is carried out through the grouting pipe, and meanwhile, pressure grouting is carried out in the bag.

5. The construction method according to claim 1, wherein the casing is driven into the soil in an inclined manner by slurry drilling in step S10.

6. Construction method according to claim 1, characterised in that the casing has a gauge of 146 x 8mm.

7. The construction method according to claim 1, wherein the jet grouting drill pipe is a phi 75 x 5mm drill pipe.

8. The construction method according to claim 1, wherein the cement paste has a water cement ratio of 0.6 to 0.8.

9. The method of claim 3, wherein the length of the bladder is no greater than the length of the jet-grouting expansion body, and the diameter of the bladder is greater than the outer diameter of the sleeve.

10. The construction method according to claim 1, wherein in step S20, a plurality of the locators are sleeved on the part of the jet grouting drill pipe in the casing pipe at intervals.