CN202936792U - Expansion shell type internal anchor head pre-stressed anchor - Google Patents

Abstract

The utility model discloses an expansion shell type internal anchor head pre-stressed anchor and belongs to the technical field of ground anchorage engineering. The pre-stressed anchor comprises an extension shell, a cone core, a mounting nut, a rod body, a mounting sleeve, a cushion plate and a locking nut. According to the expansion shell type internal anchor head pre-stressed anchor disclosed by the utility model, the pre-stressed value of the pre-stressed anchor can be remarkably increased so that the strength of an anchor body is fully exerted; the length of an inner anchorage section of the pre-stressed anchor can be effectively shortened, and the effective anchorage range of the anchor is expanded; when the expansion shell type internal anchor head pre-stressed anchor is applied to anchorage support, the size design of the cone core and the expansion shell can be carried out according to practical rock surrounding conditions so as to provide economical and safe scientific evidence for each part size of the inner anchorage section meeting practical support requirements; and the pre-stressed anchor can be subjected to mechanical installation or manual installation.

Description

Anchor head prestressed anchor in a kind of swollen shell-type

Technical field

The utility model relates to anchor head prestressed anchor in a kind of swollen shell-type, belongs to the geotechnical anchor engineering technical field.

Background technology

The prestressed anchor supporting is common a kind of surrounding rock consolidation support pattern in the underground chamber constructions such as the ground surface works such as side slope, ground deep foundation ditch and tunnel, stope.By applying prestressing force initiatively, prestressed anchor can in time be controlled absciss layer, slip, the crack of anchorage zone country rock and open, and makes country rock be in pressured state, suppresses distortion and the destruction of country rock.At present, the china natural resources exploitation just progressively develops to deep rock mass, deep rock mass has the advantages that buried depth is large, geostatic stress is high, easily occurs country rock wall caving, the serious phenomenon of plate cracking destruction after Rock Mass Unloading, and the extremely strong disasters of destructive power such as rock burst even occur sometimes.Engineering practice shows, has common prestressed anchor now under the high-ground stress condition, is difficult to suppress expansion, the control rock mass deformation weak effect of wall-rock crack, can not satisfy the requirement of rock excavation supporting under the high-ground stress condition.

China Patent Publication No. CN201802429U, date of declaration on April 20th, 2011, denomination of invention " swollen shell type center hole exhaust slip casting prestressed anchor ", this application case discloses a kind of swollen shell type center hole exhaust slip casting prestressed anchor, and the front end of this anchor pole is interior anchoring section, and the rear end is outer anchoring section, the center of anchor bar body has grout hole, be provided with steam vent in grouting on hole wall, be pasted with swollen shell at the outer wall of interior anchoring section, be positioned at rear end pocketed springs and the filler ring of swollen shell on anchor bar body.Swollen shell and the effective contact area of drill hole inner wall in this prestressed anchor on anchoring section are little, and the prestressing force that can apply is little, and when rock mass was given a shock impact, anchor-holding force of anchor bolt stability was not enough.

China Patent Publication No. CN102094421A, open June 15 2011 date, denomination of invention " job practices of a kind of prestressed anchor and this prestressed anchor of use ", this application case discloses a kind of prestressed anchor and has used the job practices of this prestressed anchor, this prestressed anchor comprises that an end has the cylindric pipe of cone shape enlarged footing, and along the body of rod of this pipe axial expansion, this body of rod is inserted into pipe after pipe is poured into cement paste in, the body of rod is divided into free segment and non-free segment, the non-open die forging of the body of rod and cement paste directly contact to form the anchoring section of the described body of rod, and body of rod free segment does not directly contact in order to carry out stretch-draw by the body of rod with cement paste and applies prestressing force.The body of rod freedom length of this prestressed anchor is 1/3 to 1/2 of body of rod total length, and in anchor pole, anchoring section length is excessive, and the anchor structure design is unreasonable.

China Patent Publication No. CN100370081C, open February 20 2008 date, denomination of invention " a kind of swollen shell anchorage head and anchor pole ", this application case discloses a kind of swollen shell anchorage head and anchor pole, formed by wedge in swollen shell and the outer wedge of swollen shell, outer cover of wedge on interior wedge, in swollen shell wedge be the bottom surface large and end face is little, with the hollow round table body of cavity, cavity is communicated with end face, bottom surface; The outer wedge of swollen shell is the hollow circular cylinder with cavity, and cavity is communicated with end face, bottom surface, the open slot on the outer wedge of swollen shell outside on the wedge surface mutually vertically, opposite direction outer wedge is divided into several limbs.When utilizing this swollen shell anchorage head and anchor pole to carry out anchoring support, can not require to carry out according to actual supporting the anchor Design of interior anchoring section, easily cause waste or produce potential danger to anchoring engineering.

Engineering practice shows, has common prestressed anchor now and is difficult to satisfy under the high-ground stress condition, and the requirement of rock excavation supporting mainly has the following disadvantages:

(1) the available anchored force of existing common prestressed anchor is not enough, and the prestress value that can apply is on the low side, and anchor rod body intensity can not be utilized effectively; Under the lower-prestressed condition, effective compressive stress district, country rock inside scope that the prestressed anchor supporting produces is little, and isolated the distribution, is not linked to be integral body, and the active support effect of prestressed anchor can not demonstrate fully.

(2) adopt bonded interior anchor head prestressed anchor (as: anchor head anchor pole in resin, the interior anchor head anchor pole of cement mortar etc.) when carrying out anchoring support, in anchor pole, anchoring section length is excessive, it is excessive that the interior anchoring section length of anchor pole accounts for anchor rod body overall length ratio, thereby anchor pole can to apply prestressed freedom length less, cause the rock mass scope of the actual effectively anchoring of anchor pole less, anchor structure is unreasonable.

(3) adopt anchor head prestressed anchor (as: wedge hair style anchor pole in mechanical type, peg block rock bolt, when expansion sleeve bolt etc.) carrying out anchoring support, in anchor pole, the anchoring section size design too much depends on the method for experience or engineering analogy, anchor Design method imperfection easily causes waste or produces potential danger to anchoring engineering.

Summary of the invention

For the problems referred to above, the utility model purpose is to provide a kind of high pre-stress, the anchor structure interior anchor head prestressed anchor of swollen shell-type reasonable, easy for installation.

For achieving the above object, technical solution of the present utility model is: anchor head prestressed anchor in a kind of swollen shell-type, comprise interior anchor head, the body of rod of anchor pole and be movably arranged on backing plate and the locking nut of body of rod tail end, described interior anchor head is made of swollen shell and cone core, the axial direction of described swollen shell has through hole, the hypomere of through hole is up-small and down-big cone-shaped, and cone angle is θ ₂, on the conical section wall of swollen shell, symmetry has four or six grooves, and the conical section outside wall surface of swollen shell is scrobicula decorative pattern shape, has circle shape groove on the outer wall of swollen shell upper end, and the epimere of described cone core is up-small and down-big cone-shaped, and cone angle is θ ₁, cone core lower end is zigzag ringwise, and the internal face of cone core is provided with internal thread, in the bellmouth that is inserted in swollen shell of cone core activity, on anchored end, external screw thread is set in the described body of rod, in the body of rod, the anchoring section lower end is threaded with the cone core, anchoring section upper end spinning mounting nuts in the body of rod.

Described taper angle theta ₂Equal taper angle theta ₁, taper angle theta ₂, taper angle theta ₁Angle be 3 °～5 °.

Owing to having adopted above technical scheme, anchor head prestressed anchor in a kind of swollen shell-type of the utility model, interior anchor head comprise cone core and swollen shell, the cone angle of cone core and swollen shell is identical, can make swollen shell evenly expand, and the increase of the contact area of cone core and swollen shell, this is conducive to firm anchored force; In the setting of swollen shell upper end circle shape groove and swollen shell, being provided with of lower end joint-cutting is beneficial to fully opening of swollen shell, increase the swell increment of swollen shell, in swollen shell, the embossing of lower end external surface is processed, can effectively increase the friction factor between swollen shell and drill hole inner wall, improve significantly the prestressing force that anchor-holding force of anchor bolt and anchor pole can apply, and then take full advantage of lever strength.And compare with traditional prestressed anchor, in a kind of swollen shell-type of the utility model, the anchor head prestressed anchor has effectively shortened anchoring section length in prestressed anchor, increase anchor pole and can apply prestressed freedom length, and then enlarge anchor pole effective anchoring scope, make the effective compressive stress district scope that forms in country rock wide, the active support effect of anchor pole is not fully exerted.

Use when in a kind of swollen shell-type of the utility model, the anchor head prestressed anchor carries out anchoring support, can be according to actual wall rock condition, bore the size design of core and swollen shell, having overcome the interior anchoring section size design of traditional anchor pole depends on experience or engineering analogy, easily causes the shortcomings and deficiencies such as waste or generation potential danger to anchoring engineering, for the size that designs the interior anchoring section each several part that satisfies actual supporting requirement provides economic, safe scientific basis.

Description of drawings

Fig. 1 is anchor head prestressed anchor structure design schematic diagram in a kind of swollen shell-type of the utility model

Fig. 2 is that in a kind of swollen shell-type of the utility model, anchor head prestressed anchor mechanical type is installed and used view

Fig. 3 is that in a kind of swollen shell-type of the utility model, the anchor head prestressed anchor is is manually installed and used view

Fig. 4 is the swollen shell structure design diagram of anchor head prestressed anchor in a kind of swollen shell-type of the utility model

Fig. 5 is the cone core structure designs schematic diagram of anchor head prestressed anchor in a kind of swollen shell-type of the utility model

Fig. 6 is anchor head prestressed anchor mechanical erection process schematic diagram in a kind of swollen shell-type of the utility model

Fig. 7 is the artificial installation process schematic diagram of anchor head prestressed anchor in a kind of swollen shell-type of the utility model

The specific embodiment

Below in conjunction with accompanying drawing, the utility model is described in further detail

See accompanying drawing

Anchor head prestressed anchor in a kind of swollen shell-type of the utility model, comprise interior anchor head, the body of rod 4 of anchor pole and be movably arranged on backing plate 6 and the locking nut 5 of the body of rod 4 tail ends, interior anchor head is made of swollen shell 2 and cone core 1, the axial direction of swollen shell 2 has through hole, the epimere of through hole is cylindric, the hypomere of through hole is up-small and down-big cone-shaped, and cone angle is θ ₂On the conical section wall of swollen shell 2, symmetry has four or six grooves, the groove width is the 2mm left and right, and groove is divided into pintongs or six lobes with swollen shell 2 symmetries, after the conical section external surface of swollen shell 2 is processed through embossing, be scrobicula decorative pattern shape, have circle shape groove on the outer wall of swollen shell 2 upper ends, depth of groove h is 2～5mm, and groove length Lh is the 25mm left and right, the epimere of cone core 1 is up-small and down-big cone-shaped, and cone angle is θ ₁, cone core 1 lower end is zigzag ringwise, and the pointed tooth number is 6～10, the pointed tooth height is the 15mm left and right, and the internal face of cone core 1 is provided with internal thread, in the bellmouth that is inserted in swollen shell 2 of cone core 1 activity, on the interior anchored end of the body of rod 4, external screw thread is set, the interior anchored end of the body of rod 4 is threaded with cone core 1.

Wherein, cone core taper angle theta ₂Equal swollen shell taper angle theta ₁, taper angle theta ₂, taper angle theta ₁Angle be 3 °～5 °.

The interior anchored end of the body of rod 4 and outer anchored end all have screw thread, and simultaneously with mounting nuts 3 be connected core 1 and be connected, outer anchored end is connected with locking nut 5 by screw thread interior anchored end, is connected with roof bolting machine 8 for convenience by screw thread, and the termination of the body of rod 4 outer anchored end is square.

Anchor head prestressed anchor in a kind of swollen shell-type of the utility model, when anchoring support was used, interior anchoring section can be bored the size design of core 1 and swollen shell 2 according to actual wall rock condition, sees accompanying drawing 4, accompanying drawing 5, and the concrete grammar step is:

1) the top external diameter φ of cone core 1 ₄Design.By character and the supporting requirement of supporting country rock, determine anchor rod body 4 diameter d and armature boring diameter D that supporting is adopted, and then determined the top external diameter φ of cone core 1 by following formula ₄:

φ ₄＝d+2δ ₂

D---anchor rod body diameter, unit: mm;

δ ₂---cone core upper end wall thickness, span 1-3mm; Concrete value size is determined by cone in-core thread parameter.

2) the conical section length l of swollen shell 2 ₁Design.Prestressed apply and the distortion of supporting country rock all can make anchor rod body 4 produce pulling force.Therefore, under the certain condition of swollen shell 2 and armature boring inwall confficient of static friction, swollen shell 2 should have enough length provides stiction; Before anchor rod body 4 is broken, sliding phenomenon should not appear between swollen shell 2 and armature boring; By the equilibrium of forces relation as can be known:

${\mathrm{\&sigma;}}_b\&CenterDot;\frac{\mathrm{\&pi;}}{4}{\mathrm{<figure-callout\; id="2"\; label="d"\; filenames="HSA00000801132300011.png,HSA00000801132300021.png"\; state="\{\{state\}\}">d</figure-callout>}}^2={\mathrm{\&sigma;}}_c\&CenterDot;\mathrm{\&pi;D}\left[l_1\right]\&CenterDot;\mathrm{\&mu;}\&CenterDot;\mathrm{\&eta;}$

Can be got by following formula:

$\left[l_1\right]=\frac{{\mathrm{\&sigma;}}_b\&CenterDot;{\mathrm{<figure-callout\; id="2"\; label="d"\; filenames="HSA00000801132300011.png,HSA00000801132300021.png"\; state="\{\{state\}\}">d</figure-callout>}}^2}{4{\mathrm{\&sigma;}}_c\&CenterDot;D\&CenterDot;\mathrm{\&mu;}\&CenterDot;\mathrm{\&eta;}}$

σ _b---anchor rod body tensile strength, unit: MPa; The value size is determined by the steel character of making anchor rod body;

D---armature boring diameter, unit: mm;

σ _c---the hole wall pressure break stress of position at the bottom of drilling hole, unit: MPa; The value size is determined by field experiment (as hydraulic fracturing);

[l ₁]---swollen shell conical section length theoretical value, unit: mm;

μ---the confficient of static friction between swollen shell outer wall and armature boring inwall, the value size is by measuring;

η---effective area contact coefficient, span 0.7-0.9.

For the purpose of safety, at the theoretical value [l of the swollen shell 2 conical section length that calculate ₁] on the basis, multiply by certain safety factor and obtain design load:

l ₁＝F _s·[l ₁]

F _s---safety factor, span: 1.1-1.2.

3) the lower external diameter φ of cone core 1 ₃Design

By the triangle geometric knowledge as can be known:

That is:

φ ₃＝2l ₂·tanθ ₂+φ ₄

θ ₂---cone core cone angle, span: 3 °-5 °, hard rock is got smaller value, and middle hard rock body is got higher value.

l ₂---cone core conical section length, unit: mm, its size equals swollen shell conical section length l ₁

4) swollen shell 2 conical section minimum thickness δ ₁Design.Swollen shell 2 produces enough swell incremenies under the effect of cone core, swollen shell is close to its anchorage effect of drill hole inner wall competence exertion, that is:

φ ₄-φ ₁≥D-φ ₁

By geometrical relationship: φ ₁-φ ₂=2l ₁Tan θ ₁+ 2 δ ₁

Thereby: $\left[{\mathrm{\&delta;}}_1\right]=\frac{D-{\mathrm{\&phi;}}_4-2{\mathrm{<figure-callout\; id="1"\; label="l"\; filenames="HSA00000801132300011.png,HSA00000801132300031.png"\; state="\{\{state\}\}">l</figure-callout>}}_1\&CenterDot;\tan {\mathrm{\&theta;}}_1}{2}$

[δ ₁]---the calculated value of swollen shell conical section minimum thickness, unit: mm;

The design load of swollen shell conical section minimum thickness

5) the internal diameter φ of swollen shell 2 ₂With external diameter φ ₁Design.By geometrical relationship:

d＜φ ₂＜φ ₄＝d+2δ ₂

Therefore, get φ ₂=d+ δ ₂:

6) cone core 1 internal thread length l ₃Design.Anchor rod body 4 will guarantee enough bonding strengths with being threaded of core 1 of cone, namely satisfies:

The shear stress of anchor rod body screw thread ${\mathrm{\&tau;}}_1=\frac{\frac{\mathrm{\&pi;}}{4}{\mathrm{<figure-callout\; id="2"\; label="d"\; filenames="HSA00000801132300011.png,HSA00000801132300021.png"\; state="\{\{state\}\}">d</figure-callout>}}^2\&CenterDot;{\mathrm{\&sigma;}}_b}{k\&CenterDot;\mathrm{\&pi;}{\mathrm{<figure-callout\; id="1"\; label="d"\; filenames="HSA00000801132300011.png,HSA00000801132300031.png"\; state="\{\{state\}\}">d</figure-callout>}}_1\&CenterDot;\mathrm{bz}}\&le;\left[{\mathrm{\&tau;}}_1\right]$

The shear stress of cone core screw thread ${\mathrm{\&tau;}}_2=\frac{\frac{\mathrm{\&pi;}}{4}{\mathrm{<figure-callout\; id="2"\; label="d"\; filenames="HSA00000801132300011.png,HSA00000801132300021.png"\; state="\{\{state\}\}">d</figure-callout>}}^2\&CenterDot;{\mathrm{\&sigma;}}_b}{k\&CenterDot;\mathrm{\&pi;}{\mathrm{<figure-callout\; id="2"\; label="d"\; filenames="HSA00000801132300011.png,HSA00000801132300021.png"\; state="\{\{state\}\}">d</figure-callout>}}_2\&CenterDot;\mathrm{bz}}\&le;\left[{\mathrm{\&tau;}}_2\right]$

K---discontinuity coefficient, span: 0.6-0.7;

d ₁, d ₂---be respectively screw thread path and Major Diam, unit: mm;

[τ ₁], [τ ₂]---be respectively body of rod screw thread and cone core screw thread shear strength, unit: MPa; For steel, [τ]=0.6[σ], [σ] is allowable tensile stress;

σ _sBe yield strength, unit: MPa, S are safety factor, span: 2-4;

B---Bottom of Thread width, for regular screw threads b=0.75p, p is the ridge distance;

Z---thread turns.

Therefore, the calculated value of cone in-core reach:

$\left[l_3\right]=p\&CenterDot;z=\frac{4}{3}b\&CenterDot;z=\max \{\frac{{\mathrm{<figure-callout\; id="2"\; label="d"\; filenames="HSA00000801132300011.png,HSA00000801132300021.png"\; state="\{\{state\}\}">d</figure-callout>}}^2{\mathrm{\&sigma;}}_{\mathrm{<figure-callout\; id="3"\; label="b"\; filenames="HSA00000801132300011.png,HSA00000801132300051.png"\; state="\{\{state\}\}">b</figure-callout>}}}{3{\mathrm{kd}}_1\left[{\mathrm{\&tau;}}_1\right]},\frac{{\mathrm{<figure-callout\; id="2"\; label="d"\; filenames="HSA00000801132300011.png,HSA00000801132300021.png"\; state="\{\{state\}\}">d</figure-callout>}}^2{\mathrm{\&sigma;}}_b}{3k{d}_2\left[{\mathrm{\&tau;}}_2\right]}\}$

, the design load l of cone in-core reach ₃=F _s[l ₃]

F _s---safety factor, span: 1.1-1.2.

According to the method for designing of above this prestressed anchor, provide a concrete calculated examples:

1) diameter d=28mm, the bore diameter D=60mm of supposition anchor rod body 4, δ ₂=2mm: the top external diameter φ of cone core 1 ₄=32mm

2) tensile strength sigma of anchor rod body 4 _b=600MPa, the hole wall pressure break stress σ of position at the bottom of drilling hole _c=55MPa, the confficient of static friction μ between swollen shell 2 outer walls and armature boring inwall=0.3, effective area contact coefficient η=0.8, the safety factor F of swollen shell conical section length _s=1.15: swollen shell conical section length l ₁=177mm

3) swollen shell 2 taper angle theta ₁=4 °, cone core 1 taper angle theta ₂=4 °: the lower external diameter φ of cone core 1 ₃=57mm

4) the conical section minimum thickness δ of swollen shell 2 ₁=1.5mm

5) the internal diameter φ of swollen shell 2 ₂=30mm, the external diameter φ of swollen shell 2 ₁=58mm

6) get discontinuity coefficient k=0.65, screw thread path d ₁=26.376mm and Major Diam d ₂=28mm, the body of rod 4 and cone core 1 yield strength are respectively 500MPa and 400MPa, safety factor S=3: the design load l of cone core 1 internal thread length ₃=132mm.

In a kind of swollen shell-type of the utility model, anchor head prestressed anchor installation and application carries out according to the following steps, sees accompanying drawing 6, and this mounting method is the mechanical type mounting method:

A with mounting nuts 3 spinnings in location, the interior anchoring section of anchor rod body 4 upper end;

B is sleeved on swollen shell 2 on cone core 1, and the interior anchoring section of anchor rod body 4 lower end screws in cone core 1, the upper surface plane contact of the lower surface of mounting nuts 3 and swollen shell 2;

C is connected the outer anchored end of anchor rod body 4 with roof bolting machine 8, roof bolting machine 8 is sent anchor pole into armature boring, roof bolting machine 8 will be bored core 1 pointed tooth and be embedded in foot of hole, roof bolting machine 8 rotation anchor rod bodies 4, drive mounting nuts 3 to armature boring bottom precession, swollen shell 2 is strutted, and swollen shell 2 closely pushes with the hole wall of armature boring;

After d cleaning, leveling armature boring scar, backing plate 6 is installed, the locking nut 5 of screwing on, and tighten locking nut 5 to predetermined prestressing force size with torque wrench or torque-indicating wrencg.

In addition, in a kind of swollen shell-type of the utility model, the anchor head prestressed anchor also can manually be installed according to the following steps, sees accompanying drawing 7:

A is enclosed within swollen shell 2 on cone core 1, after the interior anchoring section of anchor rod body 4 passes swollen shell 2, screws in cone core 1; Continue to screw cone core 1, make the interior anchored end of anchor pole be threaded to the cone core 1 screw thread end.

B is inserted in anchor rod body 4 with mounting sleeve 7 by the outer anchored end of anchor pole, makes mounting sleeve 7 hold out against swollen shell 2, and anchor pole is slowly sent into armature boring at the bottom of bore core 1 pointed tooth contact drilling hole.

C puts plain washer 9, and 5, one hands of locking nut of the screwing on locking nut 5 that screws up with a wrench squeezes at mounting sleeve 7 and pushes away under effect, and swollen shell 2 is evenly strutted by cone cores 1, closely pushes with borehole wall; An other hand is screwed in square section of anchor rod body 4 outer anchored end with spanner, with fixed core 4, avoid the body of rod 4 along with locking nut 5 rotates together.

D backs out locking nut 5 and plain washer 9, extracts mounting sleeve 7 out.

After e cleaning, leveling armature boring scar, backing plate 6 is installed, the locking nut 5 of screwing on, and tighten locking nut 5 to predetermined prestressing force size with torque wrench or torque-indicating wrencg.

Claims (2)

1. anchor head prestressed anchor in a swollen shell-type, comprise interior anchor head, the body of rod (4) of anchor pole and be movably arranged on backing plate (6) and the locking nut (5) of the body of rod (4) tail end, it is characterized in that: described interior anchor head is made of swollen shell (2) and cone core (1), the axial direction of described swollen shell (2) has through hole, the hypomere of through hole is up-small and down-big cone-shaped, and cone angle is θ ₂On the conical section wall of swollen shell (2), symmetry has four or six grooves, and the conical section outside wall surface of swollen shell (2) is scrobicula decorative pattern shape, has circle shape groove on the outer wall of swollen shell (2) upper end, the epimere of described cone core (1) is up-small and down-big cone-shaped, and cone angle is θ ₁Cone core (1) lower end is zigzag ringwise, the internal face of cone core (1) is provided with internal thread, in the bellmouth that is inserted in swollen shell (2) of cone core (1) activity, on the interior anchored end of the described body of rod (4), external screw thread is set, the interior anchoring section of the body of rod (4) lower end is threaded with cone core (1), the interior anchoring section of the body of rod (4) upper end spinning mounting nuts (3).

2. anchor head prestressed anchor in a kind of swollen shell-type as claimed in claim 1, is characterized in that: described taper angle theta ₂Equal taper angle theta ₁, taper angle theta ₂, taper angle theta ₁Angle be 3 °～5 °.

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