阅读说明：本技术 一种可回收锚杆及其施工方法 (Recyclable anchor rod and construction method thereof ) 是由 李仁民 刘飞 葛立瑞 张同 顾玉生 王涛 王建兰 于 2020-06-03 设计创作，主要内容包括：本发明公开了一种可回收锚杆,其包括一水泥土桩体和一锚索；锚索包括分锚索,每根分锚索包括顺序相接的玻纤锚筋、螺纹钢和钢绞线,玻纤锚筋的一端经一套管连接到螺纹钢的一端,螺纹钢的另一端经线杆连接器连接到钢绞线的一端上；在套管内填充有热熔材料,将玻纤锚筋和螺纹钢分别粘结在套管内；在热熔材料内埋设有第一电加热片,用于熔化位于玻纤锚筋与套管之间的热熔材料；在该锚索上连接有锚固板,锚固板具有一中心孔和环绕该中心孔布置的锚索孔,锚固板经锚索孔套设在玻纤锚筋上；该锚固板采用非金属材料制作。还提供了可回收锚杆的施工方法。本申请可减少遗留在地下的金属件,降低对后续施工的影响。(The invention discloses a recyclable anchor rod, which comprises a cement pile body and an anchor cable; the anchor cable comprises branch anchor cables, each branch anchor cable comprises a glass fiber anchor bar, deformed steel bars and a steel strand which are sequentially connected, one end of the glass fiber anchor bar is connected to one end of the deformed steel bars through a sleeve, and the other end of the deformed steel bars is connected to one end of the steel strand through a wire rod connector; the sleeve is filled with hot melting materials, and the glass fiber anchor bars and the deformed steel bars are respectively bonded in the sleeve; the first electric heating sheet is embedded in the hot melting material and used for melting the hot melting material between the glass fiber anchor bar and the sleeve; the anchor cable is connected with an anchor plate, the anchor plate is provided with a central hole and anchor cable holes arranged around the central hole, and the anchor plate is sleeved on the glass fiber anchor bars through the anchor cable holes; the anchoring plate is made of non-metallic materials. A construction method of the recyclable anchor rod is also provided. The method and the device can reduce metal pieces left underground and reduce the influence on subsequent construction.)

1. A recoverable anchor rod is characterized in that,

the anchor cable comprises a cement soil pile body and an anchor cable, wherein the cement soil pile body is provided with an enlarged head, one end of the anchor cable is positioned inside the enlarged head, the other end of the anchor cable extends along an axial direction to form an anchor head end, and the anchor head end extends out of the cement soil pile body;

the anchor cable comprises at least one branch anchor cable, each branch anchor cable comprises a glass fiber anchor bar, a deformed steel bar and a steel strand which are sequentially connected along the axis direction, two opposite ends of the glass fiber anchor bar are respectively formed into an anchoring end and a traction end, the traction end of the glass fiber anchor bar is connected to one end of the deformed steel bar through a sleeve, the other end of the deformed steel bar is connected to one end of the steel strand through a wire rod connector, and the other end of the steel strand extends out of the cement soil pile body to form an anchor head branch end; the anchor head ends of all the sub-anchor cables of the same anchor cable are jointly formed into an anchor head end;

the traction end of the glass fiber anchor bar and one end of the deformed steel bar extend into the sleeve, and the sleeve is filled with a hot melting material which respectively bonds the glass fiber anchor bar and the deformed steel bar in the sleeve so as to connect the glass fiber anchor bar and the deformed steel bar together through the sleeve; a first electric heating sheet is embedded in the hot-melt material, the first electric heating sheet is positioned between the glass fiber anchor bar and the sleeve, and the first electric heating sheet is used for melting the hot-melt material positioned between the glass fiber anchor bar and the sleeve;

the anchor cable is connected with at least one anchoring plate, the side surface of the anchoring plate in the thickness direction is called an anchoring surface, the anchoring plate is provided with a central hole and anchor cable holes which are arranged around the central hole, the central hole and the anchor cable holes both extend in the thickness direction of the anchoring plate and penetrate through two sides of the anchoring plate in the thickness direction, the anchoring plate is sleeved on the glass fiber anchor bars through the anchor cable holes, the anchoring plate is connected to the glass fiber anchor bars, and the anchoring surface of the anchoring plate is vertical to the axial direction; the anchoring plate is made of non-metallic materials.

2. The retrievable rock bolt of claim 1,

a second electric heating sheet is embedded in the hot melting material and is positioned between the deformed steel bar and the sleeve; the second electric heating plate is used for melting hot melting materials between the deformed steel bar and the sleeve; when the second electric heating plate is electrified, the hot melting material between the deformed steel bar and the sleeve can be heated and melted, and under the action of external force, the steel strand drives the deformed steel bar to be separated from the sleeve.

3. The retrievable rock bolt of claim 2,

at least one of the first electric heating sheet and the second electric heating sheet is attached to the inner wall of a sleeve, and the sleeve is a metal sleeve.

4. A retrievable rock bolt according to any one of claims 1 to 3,

the anchor cable at least comprises three sub-anchor cables, and at least two anchor plates are arranged on the anchor cable; corresponding to each branch anchor cable, each anchoring plate is provided with an anchor cable hole, each anchor cable hole is uniformly distributed around the central hole, and the branch anchor cables penetrate through the corresponding anchor cable holes; the anchoring plates are arranged at intervals along the axis direction.

5. A retrievable rock bolt according to any one of claims 1 to 3,

at least one lock catch is arranged corresponding to one anchoring plate, the lock catch is fixedly sleeved on the glass fiber anchor cable and positioned on one side of the corresponding anchoring plate, which is far away from the anchor head end, and the lock catch can abut against the anchoring plate; the lock catch is made of non-metal materials.

6. A construction method of a retrievable anchor rod for use in the construction of the retrievable anchor rod of claim 1, the method comprising the steps of:

(1) manufacturing branch anchor cables, and fixedly sleeving an anchoring plate on the anchoring ends of the branch anchor cables to form anchor cables;

(2) constructing by using a jet grouting pile machine to form a cement soil pile body with an expanded head;

(3) inserting the anchor cable into the enlarged head of the cement pile body by using a guniting pipe of the rotary guniting pile machine, and enabling the anchoring plate to reach a set position;

(4) withdrawing the guniting pipe of the rotary jet pile machine, simultaneously performing supplementary grouting, and performing guniting filling on a cavity formed when the anchor cable is inserted;

(5) after the cement soil pile body reaches the age, tensioning and locking the anchor cable;

(6) carrying out earth excavation, carrying out construction of an underground structure, and recovering the anchor cable after the construction of the underground structure is finished; when the anchor cable is recovered, the first electric heating plate is electrified to heat the hot-melt material, so that the hot-melt material is softened, the anchor cable is pulled, and the anchor cable is recovered.

7. The construction method according to claim 6,

a second electric heating sheet is embedded in the hot-melt material and is positioned between the glass fiber anchor bars and the sleeve;

when the anchor cable is recovered, the first electric heating plate is electrified to melt the hot-melt material between the glass fiber anchor bar and the sleeve, and then the steel strand is drawn to drive the deformed steel bar and the sleeve to separate from the cement soil pile body for recovery;

when the steel strand cannot be drawn out of the cement-soil pile body under the set traction force, the second electric heating sheet is electrified, so that the hot melting material between the deformed steel bar and the sleeve is melted, the steel strand is drawn again, and the deformed steel bar is driven by the steel strand to be separated from the cement-soil pile body for recycling.

8. The construction method according to claim 6,

when the cement-soil pile body is constructed, the first lifting rod speed is 10-20cm/min, the first grouting pressure is 25-30MPa, the rotating speed of the nozzle is 10-20 r/min, the cement slurry is pure cement slurry with the water-cement ratio of 0.5-0.8, and the cement doping amount is 25-35%;

when the supplementary grouting is carried out, the speed of the second lifting rod is 18-30cm/min, and the second grouting pressure is 20-25 MPa.

9. The construction method according to claim 6, wherein the radius of the cement grout spread is 30 to 50% of the radius of the enlarged head when the supplementary grouting is performed.

10. The construction method according to claim 6,

the anchoring plate is positioned in the diffusion radius of cement grout during supplementary grouting.

Technical Field

The invention relates to a recyclable anchor rod and a construction method thereof.

Background

The supporting pile fulcrum of foundation pit supporting can adopt interior support and anchor rope to realize, and interior support is with high costs, influences the major structure construction, and the anchor rope has with low costs, the fast advantage of construction, but the anchor rope need occupy a large amount of underground space, and a large amount of anchor rope anchor degree of depth scope surpass the building red line, has brought the difficult problem of violating the land planning.

In order to solve the problem, people develop a recoverable anchor cable technology, and after the anchor cable completes a task, the anchor cable is recovered, so that the problem that the anchor cable exceeds a building red line can be avoided, and the construction cost can be reduced. Currently, a variety of recyclable anchor cable technologies have been developed. However, when the anchor cable is recovered, there is a problem that a part of the anchoring elements, which are generally made of metal materials and buried in the grouting body for maintaining the stability of the anchor cable in the grouting body, is left underground and cannot be recovered, and the anchoring elements are generally large-sized anchor discs or rod elements, wherein the length of the anchor disc is between 400 mm and 600mm, and the length of the rod element is generally 2.0-2.5 m.

Because the metal anchoring parts have large volumes, the metal anchoring parts can cause certain influence on subsequent construction after being left underground. When the underground construction is continued in this area, the construction machine is damaged to some extent after striking against the metal anchors, particularly irreparable damage to cutting members such as cutters and drills, and in some cases, in order to remove the metal anchors, it is necessary to remove the metal anchors by manual excavation first, which seriously affects the efficiency of the construction in this area.

Disclosure of Invention

In order to solve the problems, the invention firstly provides a recyclable anchor rod, which can reduce metal parts left underground and reduce the influence on subsequent construction, and the specific technical scheme is as follows:

a recoverable anchor rod comprises a cement pile body and an anchor cable, wherein the cement pile body is provided with an enlarged head, one end of the anchor cable is positioned inside the enlarged head, the other end of the anchor cable extends along an axial direction to form an anchor head end, and the anchor head end extends out of the cement pile body;

the anchor cable comprises at least one branch anchor cable, each branch anchor cable comprises a glass fiber anchor bar, a deformed steel bar and a steel strand which are sequentially connected along the axis direction, two opposite ends of the glass fiber anchor bar are respectively formed into an anchoring end and a traction end, the traction end of the glass fiber anchor bar is connected to one end of the deformed steel bar through a sleeve, the other end of the deformed steel bar is connected to one end of the steel strand through a wire rod connector, and the other end of the steel strand extends out of the cement soil pile body to form an anchor head branch end; the anchor head ends of all the sub-anchor cables of the same anchor cable are jointly formed into an anchor head end;

the traction end of the glass fiber anchor bar and one end of the deformed steel bar extend into the sleeve, and the sleeve is filled with a hot melting material which respectively bonds the glass fiber anchor bar and the deformed steel bar in the sleeve so as to connect the glass fiber anchor bar and the deformed steel bar together through the sleeve; a first electric heating sheet is embedded in the hot-melt material, the first electric heating sheet is positioned between the glass fiber anchor bar and the sleeve, and the first electric heating sheet is used for melting the hot-melt material positioned between the glass fiber anchor bar and the sleeve;

the anchor cable is connected with at least one anchoring plate, the side surface of the anchoring plate in the thickness direction is called an anchoring surface, the anchoring plate is provided with a central hole and anchor cable holes which are arranged around the central hole, the central hole and the anchor cable holes both extend in the thickness direction of the anchoring plate and penetrate through two sides of the anchoring plate in the thickness direction, the anchoring plate is sleeved on the glass fiber anchor bars through the anchor cable holes, the anchoring plate is connected to the glass fiber anchor bars, and the anchoring surface of the anchoring plate is vertical to the axial direction; the anchoring plate is made of non-metallic materials. The anchoring plate is preferably made of glass fiber reinforced plastic material.

The sleeve is preferably a steel sleeve, and the length of the sleeve is 0.5-0.8 m. The glass fiber anchor bars are also called glass fiber bars or glass fiber anchor bars. The wire rod connector is used for connecting the thread steel and the steel strand together, is mature at present, and can be directly purchased with products sold in the market.

One end of the first electric heating piece at least reaches the end face of one end of the glass fiber anchor bar in the sleeve, and the other end of the first electric heating piece at least reaches the end face of one end of the sleeve departing from the anchor head end. The first electric heating plate is preferentially started from the end face of one end, deviating from the anchor head end, of the sleeve to the end face of one end, located in the sleeve, of the deformed steel bar, so that the first electric heating plate can comprehensively heat the hot-melt material surrounding the glass fiber anchor bars to enable the hot-melt material to be melted.

In this application, the anchor rope is by fine anchor bar of glass, screw-thread steel and steel strand wires are connected and are formed, steel strand wires wherein play the effect that produces prestressing force, screw-thread steel is used for linking together fine anchor bar of glass and steel strand wires, although fine anchor rope of glass has higher tensile strength, but the fastener that is difficult for adopting the centre gripping formula is connected it on steel strand wires, in this application, adopt sleeve pipe and screw-thread steel switching, make fine anchor rope of glass be connected to steel strand wires on, when retrieving, utilize first electric heating plate to melt hot melt material, make the steel sleeve pipe break away from glass anchor bar, accomplish the recovery of steel strand wires, and leave fine anchor rope of glass underground, do not retrieve. Because the glass fiber anchor cable is a brittle material, the glass fiber anchor cable is very easy to break after being impacted by external force, so that the machine continuously constructed in the area cannot be damaged, and the glass fiber anchor cable cannot cause environmental pollution in the area. The glass fiber anchor cable is adopted to replace a metal anchoring part in the prior art, so that the damage to subsequent equipment constructed in the area can be effectively avoided.

The anchor board is arranged in increasing the stability of anchor rope in the cement soil pile body, and in this application, the non-metallic material preparation of anchor board adoption glass steel class can not retrieve, remains in the underground, because the anchor board adopts non-metallic material preparation, preferably adopts the glass steel material preparation, and when follow-up continuation construction in this region, the anchor board also can not lead to the fact the damage to construction machinery, and in addition, the anchor board also easily is broken by construction equipment, can not lead to the fact the influence to the construction progress.

Furthermore, a second electric heating sheet is embedded in the hot melting material and is positioned between the deformed steel bar and the sleeve; the second electric heating plate is used for melting hot melting materials between the deformed steel bar and the sleeve; when the second electric heating plate is electrified, the hot melting material between the deformed steel bar and the sleeve can be heated and melted, and under the action of external force, the steel strand drives the deformed steel bar to be separated from the sleeve.

One end of the second electric heating piece at least reaches the end face of one end of the deformed steel bar in the sleeve, and the other end of the second electric heating piece at least reaches the end face of one end of the sleeve facing the anchor head end. The second electric heating plate is preferentially arranged from the end face of one end, located in the sleeve, of the glass fiber anchor bar to the end face of one end, facing the anchor head, of the sleeve, so that the second electric heating plate can comprehensively heat the hot-melt material surrounding the deformed steel bar to melt the hot-melt material.

When retrieving the anchor rope, if because of the soil cement pile body is too big to sheathed tube wrapping power, lead to the sleeve pipe can not break away from the soil cement pile body, when unable completion anchor rope was retrieved, then switch on the second electric heating piece, heat the hot melt material between sleeve pipe and the screw-thread steel, make the hot melt material between screw-thread steel and the sleeve pipe heated and melt, make the screw-thread steel break away from the sleeve pipe under steel strand wires's drive, accomplish the recovery to steel strand wires.

Further, at least one of the first electric heating plate and the second electric heating plate is attached to the inner wall of the sleeve, and the sleeve is a metal sleeve.

When the first electric heating plate or the second electric heating plate is electrified, the generated heat energy is transmitted through the sleeve, so that the hot-melt material between the sleeve and the glass fiber anchor cable or between the sleeve and the deformed steel bar is heated, and the situation that the local hot-melt material cannot be melted due to insufficient heat is avoided.

Specifically, the anchor cable at least comprises three branch anchor cables, and at least two anchoring plates are arranged on the anchor cable; corresponding to each branch anchor cable, each anchoring plate is provided with an anchor cable hole, each anchor cable hole is uniformly distributed around the central hole, and the branch anchor cables penetrate through the corresponding anchor cable holes; the anchoring plates are arranged at intervals along the axis direction.

Under the connection of the anchoring plates, the branch anchor cables of each anchor cable and the anchoring plates form a cage-shaped structure together, the cage-shaped structure is similar to a reinforcement cage of a reinforcement structure, the connection strength between the anchor rod and the cement soil pile body is improved, the glass fiber anchor bars can be firmly kept in the cement soil pile body, and the pulling resistance of the anchor rod is ensured.

Because when placing the anchor plate in the cement soil pile body, hardly guarantee with the anchor face perpendicular to axis direction of anchor plate, need carry out secondary positioning under the pulling of each branch anchor rope to ensure that the anchor face of anchor plate can be perpendicular to axis direction. When every anchor rope only comprises a branch anchor rope or two branch anchor ropes, when concrete construction, can't ensure the anchor face perpendicular to axis direction of anchor board, and when setting up three at least branch anchor ropes, only need when making the anchor rope, make the anchor face perpendicular to anchor rope's of anchor board extending direction can, after placing the anchor board in the soil cement pile body, even when placing the anchor board in the soil cement pile body, the anchor face of anchor board can not the perpendicular to axis direction, only need follow the axis direction and stimulate each branch anchor rope, can make the anchor face perpendicular to axis direction of anchor board.

Furthermore, at least one lock catch is arranged corresponding to one anchoring plate, the lock catch is fixedly sleeved on the glass fiber anchor cable and positioned on one side of the corresponding anchoring plate, which is far away from the anchor head end, and the lock catch can abut against the anchoring plate; the lock catch is made of non-metal materials. The anchor plate is preferably bonded to the corresponding shackle with an adhesive.

When carrying out the stretch-draw to the anchor rope, under the restriction of hasp, the fine anchor bar of glass is connected on the anchor board steadily, avoids the stretch-draw in-process, and the fine anchor bar of glass produces great removal in the cement soil pile body, has further guaranteed the stability of the fine anchor bar of glass in the cement soil pile body. When the anchoring plate is adhered to the glass fiber anchor bars simply by using the adhesive, the contact area between the glass fiber anchor bars and the anchoring plate is too small, the connection strength between the glass fiber anchor bars and the anchoring plate is insufficient, and the glass fiber anchor bars are easily separated from the anchoring plate under the pull-down of external force, so that the failure of the anchoring plate is caused.

Secondly, this application still provides a construction method of recoverable stock, and its construction with above-mentioned recoverable stock, its step includes:

(1) manufacturing branch anchor cables, and fixedly sleeving an anchoring plate on the anchoring ends of the branch anchor cables to form anchor cables;

(2) constructing by using a jet grouting pile machine to form a cement soil pile body with an expanded head;

(3) inserting the anchor cable into the enlarged head of the cement pile body by using a guniting pipe of the rotary guniting pile machine, and enabling the anchoring plate to reach a set position;

(4) withdrawing the guniting pipe of the rotary jet pile machine, simultaneously performing supplementary grouting, and performing guniting filling on a cavity formed when the anchor cable is inserted;

(5) after the cement soil pile body reaches the age, tensioning and locking the anchor cable;

(6) carrying out earth excavation, carrying out construction of an underground structure, and recovering the anchor cable after the construction of the underground structure is finished; when the anchor cable is recovered, the first electric heating plate is electrified to heat the hot-melt material, so that the hot-melt material is softened, the anchor cable is pulled, and the anchor cable is recovered.

In the construction method, firstly, the cement-soil pile body is constructed, before the cement soil is not solidified, one end of the anchoring plate carrying the anchor rope is inserted into the cement-soil pile body by using the shotcrete pipe of the rotary shotcrete machine, when the anchor rope is inserted into the cement-soil pile body, the structure in the cement-soil pile body can be partially damaged, in the process of withdrawing the shotcrete pipe, supplementary grouting is carried out in the cement-soil pile body, the central area of the cement-soil pile body is strengthened, the area where the cement grout is diffused during the supplementary grouting is called as a pile core, and all the anchoring plates are positioned in the pile core so as to ensure the strength of the cement-soil pile body and the stability of the anchoring plates in the cement-soil pile body. When the cement soil pile body is subjected to supplementary grouting, the cement soil grout can be used for grouting a cavity caused by inserting the anchoring plate, and the grout can enter holes and gaps caused by solidification of the cement soil pile body, so that the effect of reinforcing the cement soil pile body is achieved, and the strength of the cement soil pile body is improved. The pile core formed during supplementary grouting wraps the anchoring plate, so that the anchoring plate and the cement soil pile body form a whole.

At present, when the anchor rod is manufactured by adopting the jet grouting pile machine, the construction of a pile hole is firstly completed, then the anchor cable is inserted into the pile hole, then grouting is carried out in the pile hole to form a cement-soil pile body, and meanwhile, one end of the anchor cable is fixed in the cement-soil pile body. By adopting the construction method, although the construction method is mature, the anchor cable is inserted into the pile hole and then grouted, and the anchor cable is deviated from the set position as well, so that the anchor cable is positioned at one side of the cement soil pile body, and a special support structure is required to be arranged to ensure that the anchor cable is positioned at the set position in the pile hole. In addition, in the solidification process of cement soil, the cement soil can produce certain shrink, and crackle in the cement soil pile body reduces the intensity of pile body, and in this application, supplementary slip casting is carried out in the cement soil pile body, can pack the crackle that the cement soil pile body produced in the solidification process, guarantees the intensity of cement soil pile body.

Furthermore, a second electric heating sheet is embedded in the hot-melt material and is positioned between the glass fiber anchor bars and the sleeve; when the anchor cable is recovered, the first electric heating plate is electrified to melt the hot-melt material between the glass fiber anchor bar and the sleeve, and then the steel strand is drawn to drive the deformed steel bar and the sleeve to separate from the cement soil pile body for recovery; when the steel strand cannot be drawn out of the cement-soil pile body under the set traction force, the second electric heating sheet is electrified, so that the hot melting material between the deformed steel bar and the sleeve is melted, the steel strand is drawn again, and the deformed steel bar is driven by the steel strand to be separated from the cement-soil pile body for recycling.

When retrieving the anchor rope, if because of the soil cement pile body is too big to sheathed tube wrapping power, lead to the sleeve pipe can not break away from the soil cement pile body, when unable completion anchor rope was retrieved, then switch on the second electric heating piece, heat the hot melt material between sleeve pipe and the screw-thread steel, make the hot melt material between screw-thread steel and the sleeve pipe heated and melt, make the screw-thread steel break away from the sleeve pipe under steel strand wires's drive, accomplish the recovery to steel strand wires.

Specifically, when the cement-soil pile body is constructed, the first lifting rod speed is 10-20cm/min, the first grouting pressure is 25-30MPa, the rotating speed of a nozzle is 10-20 r/min, cement slurry is pure cement slurry with a water-cement ratio of 0.5-0.8, and the cement mixing amount is 25-35%; the cement mixing amount refers to the cement amount contained in the formed cement soil pile body by taking soil as a reference;

when the supplementary grouting is carried out, the speed of the second lifting rod is 18-30cm/min, and the second grouting pressure is 20-25 MPa. The first lifting rod speed and the second lifting rod speed both refer to the lifting speed of the guniting pipe during construction. And the second lifting rod speed is greater than the first lifting rod speed, and the second grouting pressure is less than the first grouting pressure.

In this application, when supplementary slip casting, adopt great pressure and higher lifter speed relatively, owing to when supplementary slip casting, have the parcel of soil cement pile body on every side, the grout of injection can be restricted in a minizone, under above-mentioned second lifter speed and second slip casting pressure, can guarantee the intensity of soil cement pile body. When the cement soil pile body is constructed, the soil body needs to be cut simultaneously, so that the first lifting rod speed and the first grouting pressure are higher than the second lifting rod speed and the second grouting pressure.

Furthermore, in order to avoid forming a relatively independent cement soil structure during supplementary grouting, the diffusion radius of cement slurry is 30-50% of the radius of the enlarged head during supplementary grouting. After the supplementary grouting is finished, a relatively independent structure cannot be formed in the cement pile body, and the cement pile body is kept to be an integral structure.

Further, the anchoring plate is located within the diffusion radius of the cement grout during supplementary grouting.

Namely, all the anchoring plates are positioned in the diffusion radius of cement grout during supplementary grouting and are uniformly arranged at intervals. The anchor rope in this application is after the construction of accomplishing the cement soil pile body, before cement soil does not solidify, insert the enlarged footing with the one end of the anchor rope including the anchor board in, when inserting the anchor rope in the enlarged footing, can cause partial destruction to the internal structure of cement soil pile, the one end that utilizes the shotcrete pipe of stirring stake machine with the anchor board and carry the anchor rope inserts the internal back of cement soil pile, utilize the shotcrete pipe to carry out the slip casting in the cement soil pile body, strengthen the center district of cement soil pile body, and make all anchor boards all be located the diffusion radius of cement thick liquid, with the intensity of guaranteeing the cement soil pile body, and the stability of anchor board in the cement soil pile body.

Drawings

FIG. 1 is a schematic diagram of an underground structure under construction using an embodiment of the present invention.

Fig. 2 is an enlarged view of a portion D in fig. 1.

Fig. 3 is a view from a-a in fig. 2.

Fig. 4 is an enlarged view of a portion E in fig. 2, and for clarity, only the relevant structure of the anchor cable is shown in fig. 4.

Fig. 5 is a view in the direction B-B in fig. 4.

Fig. 6 is a view in the direction of C-C in fig. 4.

Detailed Description

Referring to fig. 1, fig. 1 is a partial view of an underground structure as it is being constructed using an embodiment of the present application.

In fig. 1, the direction of arrow M indicated at an appropriate position indicates the axial direction.

The retrievable anchor 200 is located in the soil around the foundation pit 121, the retrievable anchor 200 includes a soil cement pile 30 and the anchor line 10, the soil cement pile 30 extends along the axial direction, and the soil cement pile 30 is formed with an enlarged head 32.

One end of the anchor cable 10 is located inside the enlarged head, and the other end of the anchor cable 10 extends along the axial direction to form an anchor head end 15, and the anchor head end 15 extends out of the cement pile body 30. In this embodiment, the anchor head 15 is fixed to the purlin 111 by the lock 122 after being tensioned, and the purlin 111 is erected on the support piles 110 of the foundation pit 121. The pit 121 is used to construct an underground structure 125. In fig. 1, reference numeral 100 denotes a ground surface.

The enlarged head 32 is located at the end of the soil cement pile body 30 remote from the anchor end 15.

Referring to fig. 2-6, in the present embodiment, one anchor cable 10 includes six sub-anchor cables 105, each sub-anchor cable 105 includes a glass fiber anchor 13, a deformed steel bar 12 and a steel strand 11 connected in sequence along the axial direction, wherein the deformed steel bar 12 is made of a fine-rolled deformed steel bar. It will be appreciated that in other embodiments, only one sub-cable may be provided per cable, or two sub-cables, or more sub-cables, for example three, four or ten sub-cables, but it is recommended that at least three sub-cables be provided to facilitate the installation of the anchor plates described below.

The opposite ends of the glass fiber tendon 13 are formed as an anchoring end 131 and a pulling end 132, respectively. The traction end 132 of the glass fiber anchor bar 13 is connected to one end of the deformed steel bar 12 through the sleeve 17, the other end of the deformed steel bar 12 is connected to one end of the steel strand 11 through the rod connector 16, the other end of the steel strand 11 extends out of the cemented soil pile body to form an anchor head branch end, and the anchor head branch ends of all the branch anchor ropes of the same anchor rope are jointly formed into the anchor head end.

The wire rod connector 16 is used for connecting the thread steel 12 and the steel strand 11, and is mature at present, and commercially available products can be directly purchased.

In the sleeve, along the length direction of the sleeve, a gap of 2-5mm is formed between the glass fiber anchor cable and the deformed steel bar.

The traction end of the glass fiber anchor bar 11 and one end of the deformed steel bar 12 both extend into the connected sleeve 17, the sleeve is filled with a hot melting material 14, and the hot melting material respectively bonds the glass fiber anchor bar and the deformed steel bar in the sleeve so that the glass fiber anchor bar and the deformed steel bar are connected together through the sleeve.

The sleeve 17 is made of a carbon steel pipe with the length of 0.6 meter, and internal threads are arranged in the sleeve. The sleeve is filled with a hot melt material 14, in this embodiment, a hot melt epoxy resin is specifically used as the hot melt material. The hot melt material bonds the glass fiber anchor bars 13 and the deformed steel bars 12 in the sleeve 17 respectively, so that the glass fiber anchor bars and the deformed steel bars are connected together. It is understood that in other embodiments, the sleeve may be made of other high-strength alloy steel pipes or non-ferrous metal pipes.

The first electric heating plate 18 and the second electric heating plate 19 are embedded in the hot melt material, and in the present embodiment, both the first electric heating plate 18 and the second electric heating plate 19 are sheet-shaped electric heating plates. The first electric heating plate 18 and the second electric heating plate 19 are attached to the inner wall of the sleeve. It will be appreciated that in other embodiments, only the first electrical heating strip 18 or the second electrical heating strip 19 may be attached to the inner wall of the sleeve, although attachment to the inner wall of the sleeve is preferred.

When the first electric heating piece 18 or the second electric heating piece 19 is attached to the inner wall of the sleeve, when the first electric heating piece and the second electric heating piece are electrified, the generated heat energy is transmitted through the sleeve, so that all hot-melt materials in the sleeve are heated, and the situation that the local hot-melt materials cannot be melted due to insufficient heat is avoided.

In this embodiment, the first electric heating plate 18 is located between the glass fiber anchor bar and the sleeve, and the first electric heating plate starts from the end surface of the end of the sleeve away from the anchor head end to the end surface of the end of the deformed steel bar located in the sleeve.

The second electric heating plate 19 is arranged between the deformed steel bar and the sleeve, and the second electric heating plate starts from the end surface of one end of the glass fiber anchor bar in the sleeve and ends at the end surface of one end of the sleeve facing the anchor head end.

It is necessary to clean the surface of the deformed steel bar and the inner surface of the sleeve so that the hot-melt material can be tightly adhered to the surface of the deformed steel bar and the inner surface of the sleeve. And simultaneously, the outer surface of the sleeve and the glass fiber anchor bars are cleaned, so that the sleeve and the surrounding cement soil are well bonded.

The end of the steel strand 11 connected to the pole connector 16 is stripped of the steel strand and the stripped portion is cleaned to allow the pole connector to be stably connected to the steel strand.

In this embodiment, three anchor plates 41 are provided corresponding to the anchor cable, and the anchor plates are made of a non-metallic material. The lateral surface of the anchor plate in the thickness direction is referred to as an anchor surface, and each anchor plate 41 has a central hole 411 and six anchor line holes 412 uniformly arranged around the central hole 411, and the central hole and the anchor line holes extend in the thickness direction of the anchor plate and penetrate through both sides of the anchor plate in the thickness direction. Each anchor cable hole 412 corresponds to one glass fiber anchor bar 13, and the anchor plate 41 is sleeved on the glass fiber anchor bar through the anchor cable hole 412. The anchoring plates are arranged at intervals along the axis direction. For clarity, the fiberglass tendons in the two anchor cable holes in fig. 3 are removed.

The cover is equipped with hasp 42 on fine anchor bar 13 of glass, on every fine anchor bar 13 of glass, corresponds to every anchor plate 41, all is provided with a hasp 42, and this hasp adopts non-metallic material preparation, specifically adopts the glass steel material preparation in this embodiment, and the hasp adopts epoxy to bond on fine anchor bar 13 of glass, and every hasp all is located one side that deviates from the anchor head end of its anchor plate that corresponds. Utilize epoxy to bond the hasp on fine anchor bar 13 of glass, when carrying out stretch-draw to the anchor rope, the hasp supports and leans on the one side that deviates from the anchor head end of anchor plate to make fine anchor bar 13 of glass keep on the anchor plate, utilize the stability of anchor plate in the cement soil pile body, avoid the anchor rope to break away from the cement soil pile body.

When the anchoring plate is installed, the anchoring surface of the anchoring plate is perpendicular to the extending direction of the glass fiber anchor bars 13 as much as possible, so that the stability of the anchoring plate in the cement-soil pile body is improved.

In order to facilitate the insertion of the anchoring plate into the cement-soil pile body, in the embodiment, the lock catch is bonded on the corresponding anchoring plate by using epoxy resin, and when the anchoring plate is inserted into the cement-soil pile body, the lock catch and the corresponding flange are kept together, so that the movement amount of the glass fiber anchor bars is reduced when the anchor cable is tensioned. In order to avoid the separation of the anchoring plate from the corresponding lock catch, it can be understood that, in other embodiments, the anchoring plate and the corresponding lock catch may be bonded together by using epoxy resin or other bonding agents, so that when the anchor cable is inserted into the cement-soil pile body, since cement soil is bonded between the anchoring plate and the lock catch, when the anchor cable is tensioned, the anchoring surface of the anchoring plate is not perpendicular to the extending direction of the anchor cable, which may affect the stress of the anchoring plate in the cement-soil pile body.

The use of the first and second electric-heating sheets 18 and 19 is explained below. When the first electric heating plate 18 is electrified, the hot melting material between the sleeve and the glass fiber anchor bar is heated and melted, and the anchor head end is pulled by a jack or a winch, so that the steel strand drives the deformed steel bar and the sleeve to be separated from the glass fiber anchor bar together for recycling. When retrieving the anchor rope, if too big because of the soil cement pile body to sheathed tube wrapping power, lead to the sleeve pipe can't break away from the soil cement pile body, when unable completion anchor rope was retrieved, then switch on the second electric heating piece, heat the hot melt material between sleeve pipe and the screw-thread steel, make the hot melt material between screw-thread steel and the sleeve pipe heated and melt, make the screw-thread steel break away from the sleeve pipe under steel strand wires's drive, accomplish the recovery to steel strand wires.

No matter which kind of recovery mode, glass fiber anchor bar and anchor plate all remain underground, because glass fiber anchor bar and anchor plate are non-metallic material preparation, can not cause the influence to this regional follow-up construction. The deformed steel bars are recycled along with the steel strands and cannot be kept underground, so that influence on subsequent construction is avoided.

In part of the construction process, the sleeve can be kept underground, and the length of the sleeve is set within 0.8 meter, so that the subsequent construction in the area cannot be influenced, and the inconvenience of the subsequent construction in the anchor rod construction area is avoided during the anchor rod construction.

The construction method of the recoverable anchor rod 200 is described as follows, and specifically includes the following steps:

(1) the other end of the deformed steel bar 12 and one end of the glass fiber anchor bar 13 are inserted into the sleeve, the first electric heating piece 18 and the second electric heating piece 19 are placed into the sleeve, the hot melt material in a molten state is injected into the sleeve, the sleeve is filled with the hot melt material, the part, located in the sleeve, of the glass fiber anchor bar 13 and the part, located in the sleeve, of the deformed steel bar 12 are completely wrapped, the hot melt material is cooled until the room temperature, the hot melt material is solidified, and the glass fiber anchor bar 13 and the deformed steel bar 12 are connected together. The end of the steel strand 11 remote from the rod connector 16 becomes the anchor head sub 15.

Sleeving the anchoring plate 41 and the lock catches 42 on the glass fiber anchor bars 13, then bonding the anchoring plate 41 and the lock catches 42 on the anchoring ends 131 by using epoxy resin, enabling the anchoring plate 41 and the corresponding lock catches 42 to abut against each other, and enabling the lock catches 42 to be located on one sides of the corresponding anchoring plates 41, which are far away from the sleeve.

One ends of the six sub-anchor cables are connected together through the anchor plate, and the other ends are bound together to form the anchor cable 10. All anchor head sections of the same cable bolt together form an anchor head end.

(2) And constructing a support pile 110, excavating a foundation pit 121, and installing an enclosing purlin 111. When the construction elevation of the recoverable anchor rod 200 is reached, the excavation of the foundation pit is suspended, the rotary jet pile machine is used for construction, the cement soil pile body 30 is formed, and the enlarged head 32 is formed at one end, far away from the foundation pit, of the cement soil pile body 30.

(3) The shotcrete pipe of the rotary jet pile machine is inserted into the central hole of the anchoring plate, and then the end of the anchor cable 10 with the anchoring plate is inserted into the enlarged head 32 of the cemented soil pile body 30 by the shotcrete pipe, and the anchoring plate reaches the set position.

(4) And withdrawing the guniting pipe of the rotary jet pile machine, simultaneously performing supplementary grouting, and guniting and filling the cavity formed when the anchor cable is inserted.

(5) And after the cement soil pile body reaches the age, tensioning the anchor cable and locking the anchor cable to the surrounding purlin 111.

(6) And excavating earth, constructing the underground structure, and recovering the anchor cable after the construction of the underground structure is completed.

When the anchor cable is recovered, the first electric heating plate is electrified to heat the hot-melt material between the sleeve and the glass fiber anchor cable, so that the hot-melt material is melted, the anchor head end is pulled by the winch, namely, the anchor cable is pulled, and under the drive of the steel strand, the deformed steel bar drives the sleeve to be pulled out from the cement soil pile body together, so that the steel strand is recovered.

When the anchor cable is pulled, if the set traction force is reached, the steel strand can not be pulled out, the second electric heating plate is electrified, so that the hot melting material between the deformed steel bar and the sleeve is melted, the steel strand is pulled again, and the steel strand drives the deformed steel bar to be separated from the cement soil pile body for recycling.

In this embodiment, when constructing the cement-soil pile body, the first lifting rod speed is 15cm/min, the first grouting pressure is 30MPa, the rotation speed of the nozzle is 17 rpm, the cement slurry is pure cement slurry with a water-cement ratio of 0.5, and the cement mixing amount is 30%.

When the supplementary grouting is carried out, the speed of the second lifting rod is 22cm/min, and the second grouting pressure is 22 MPa.

It is understood that in other embodiments, when constructing the cement-soil pile body, the first lifting rod speed can also be 10cm/min, 12cm/min, 18cm/min or 20cm/min, the first grouting pressure can also be 25MPa, 26MPa or 28MPa, the rotating speed of the nozzle is 10 r/min, 15 r/min or 20 r/min, the cement slurry is pure cement slurry with a water-cement ratio of 0.6, 0.7 or 0.8, and the cement mixing amount is 25% or 35%.

When the supplementary grouting is carried out, the speed of the second lifting rod can be 18cm/min, 20cm/min, 25cm/min or 30cm/min, and the second grouting pressure can be 20MPa, 24MPa or 25 MPa.

When the supplementary grouting is carried out, the speed of the second lifting rod is higher than that of the first lifting rod, and the second grouting pressure is lower than that of the first grouting pressure.

In this embodiment, when the supplementary grouting is performed, the diffusion radius of the cement grout is 35% of the radius of the enlarged head. It is understood that in other embodiments, the radius of the cement slurry spread is 30%, 40%, 45%, or 50% of the radius of the enlarged head when the supplemental grouting is performed.