CN111827316A - Combined anti-sliding structure with prestressed anchor cables additionally arranged on existing pile and construction method - Google Patents
Combined anti-sliding structure with prestressed anchor cables additionally arranged on existing pile and construction method Download PDFInfo
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- CN111827316A CN111827316A CN202010807203.7A CN202010807203A CN111827316A CN 111827316 A CN111827316 A CN 111827316A CN 202010807203 A CN202010807203 A CN 202010807203A CN 111827316 A CN111827316 A CN 111827316A
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D17/00—Excavations; Bordering of excavations; Making embankments
- E02D17/20—Securing of slopes or inclines
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D17/00—Excavations; Bordering of excavations; Making embankments
- E02D17/20—Securing of slopes or inclines
- E02D17/207—Securing of slopes or inclines with means incorporating sheet piles or piles
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D5/00—Bulkheads, piles, or other structural elements specially adapted to foundation engineering
- E02D5/22—Piles
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D5/00—Bulkheads, piles, or other structural elements specially adapted to foundation engineering
- E02D5/74—Means for anchoring structural elements or bulkheads
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Abstract
The invention discloses a combined anti-sliding structure with prestressed anchor cables added to an existing pile and a construction method, wherein a cantilever section of the existing anti-sliding pile is drilled, and a vertical prestressed anchor cable A and a plurality of rows of diagonal prestressed anchor cables B are added to enhance and improve the existing anti-sliding pile and optimize the structural stress; the method aims to optimize the pile body internal force distribution of the existing pile, provide enough anchoring force for the existing pile, and share a part of landslide thrust so as to reinforce and manage the engineering instability caused by slope toe excavation.
Description
Technical Field
The invention relates to the technical field of excavation supporting, in particular to a combined anti-sliding structure with an existing pile additionally provided with a prestressed anchor cable and a construction method.
Background
Landslide control is a disaster-resistant project with huge investment, complex technology and dangerous and difficult construction. China is a country with serious landslide disasters, and for years, in order to ensure the safety of lives and properties of people and ensure the smooth progress of economic construction, the country consumes a large amount of manpower, material resources and financial resources on landslide prevention and control work.
In the later stage of the 20 th century and the 60 s, the anti-slide pile is used as a novel geotechnical engineering reinforcing technology, has the advantages of being smaller than an excavation surface of a retaining wall, small in masonry volume, high in anti-slide strength, high in construction speed and the like, is quickly popularized and applied in China, and is still used in the fields of highways, railways and the like in a large scale. Because the anti-slide piles in the existing highway landslide control are arranged at positions which are thinner in landslide, smaller in thrust, higher in foundation strength of the anchoring section and beneficial to anti-slide. In this case, the embedded type slide resistant piles outside a certain distance (later extension range) from the outside of the road are widely used in the management of the landslide along the line.
With the development of social economy, projects such as highway capacity expansion, trunk line upgrading and reconstruction and the like emerge in large quantity; in the road excavation and extension scheme, existing landslides along the line cannot be avoided, the rock-soil mass at the front slope foot of the embedded type anti-slide pile needs to be excavated, and at the moment, safe excavation and retreatment of the existing side slope become one of the control projects (difficult problems) in engineering construction. After a resistance-providing soil body is excavated before the embedded type anti-slide pile, the existing anti-slide pile may have the phenomenon that an upper pile body is exposed to form a cantilever section or the front edge width of the pile body is insufficient, and compared with the increased landslide thrust, enough anchoring force and anti-slide force cannot be provided, so that the landslide body is damaged by instability due to excavation of a road extension slope foot.
Disclosure of Invention
The invention aims to provide a combined anti-sliding structure with a pre-stressed anchor cable additionally arranged on an existing pile and a construction method, and aims to solve the technical problem that a landslide body is unstable and damaged due to excavation of a road expansion slope toe because sufficient anchoring force and anti-sliding force cannot be provided in the prior art.
The invention is realized by the following technical scheme:
a combined anti-sliding structure with an existing pile additionally provided with a prestressed anchor cable comprises an existing anti-sliding pile body, wherein the pile body is divided into a cantilever section and an embedded section, and the embedded section is embedded in a stable rock-soil body below a sliding surface;
the top of the cantilever section of the pile body is provided with a vertical prestressed anchor cable A, the upper end of the vertical prestressed anchor cable A is connected with the top of the cantilever section of the pile body, and the lower end of the vertical prestressed anchor cable A vertically penetrates through the bottom of the embedded section of the pile body from the top of the cantilever section of the pile body downwards and extends along the direction of the embedded section;
and a cable-stayed prestressed anchor cable B is also arranged on the cantilever section of the pile body, the lower end of the cable-stayed prestressed anchor cable B is anchored in the stable rock-soil body behind the sliding surface, the upper end of the cable-stayed prestressed anchor cable B is connected with the cantilever section of the pile body, and an included angle theta is formed between the cable-stayed prestressed anchor cable B and the horizontal plane.
Furthermore, distribution ribs and stirrups are arranged in the pile body, and bending-resistant reinforcing steel bars are arranged on the tension side of the pile body;
and drilling an anchor rope preformed hole A for placing the vertical prestressed anchor rope A at the symmetrical position of the A-A central axis of the cantilever section of the pile body outside the protective layer of the bending-resistant reinforcing steel bar at the tension side of the pile body.
Furthermore, one or more anchor cable preformed holes A are formed in the top of the cantilever section of the pile body;
the vertical prestressed anchor cable A consists of a fastening head, a free section and an anchoring section, wherein the fastening head consists of a cement anchor pier, a steel base plate and an anchorage device;
and a plastic gasket is arranged between the cement anchor pier and the pile body.
And further, drilling a cable-stayed anchor cable preformed hole B for placing the cable-stayed prestressed anchor cable B at the central axis of the front side of the pile body at the position, which is not smaller than 300mm from the top of the pile top, of the cantilever section of the pile body.
Furthermore, one or more anchor cable preformed holes B are formed in the central axis of the front side of the pile body, which is located at the position, with the distance from the cantilever section of the pile body to the top of the pile top being not less than 300 mm;
the cable-stayed prestressed anchor cable B consists of a fastening head, a free section and an anchoring section, wherein the fastening head consists of a cement anchor pier, a steel backing plate and an anchorage device;
and a plastic gasket is arranged between the cement anchor pier and the pile body.
Further, the plastic gasket is a rubber gasket or a nylon gasket with the layer thickness of 30mm, and the boundary size of the plastic gasket is 50mm larger than that of the cement anchor pier.
Furthermore, the prestressed anchor cable A and the prestressed anchor cable B are both made of 4-8 strands of steel stranded wires;
the prestressed anchor cable A is divided into an anchoring section A and a free section A; the anchoring section A is an anchoring section anchored in a stable rock-soil body below the pile body, and the free section A is the distance length from the top of the prestressed anchor cable A to the pile bottom of the pile body plus 500 mm;
the prestressed anchor cable B is divided into an anchoring section B and a free section B, the anchoring section B is an anchoring section anchored in a stable rock-soil body behind the sliding surface, and the free section B is the distance length from the top of the prestressed anchor cable B to the sliding surface plus 1000 mm.
The invention also provides a construction method of the combined anti-sliding structure with the pre-stressed anchor cables additionally arranged on the existing pile, which comprises the following steps:
s1: collecting a structural design drawing and a completion drawing of the existing slide-resistant pile body in a construction stage; a reinforcing steel bar detector is adopted to detect the structure and the reinforcing steel bars of the pile body of the existing slide-resistant pile by an electromagnetic induction method;
s2: according to the detection result of the steel bar detector, drilling an anchor rope preformed hole A for embedding the pre-stressed anchor rope A by adopting a concrete drilling and core-taking machine at the symmetrical position of the central axis A-A at the top of the cantilever section of the pile body outside the protective layer of the anti-bending steel bar at the tension side of the pile body; after the anchor cable preformed hole A is drilled, drilling in a subsequent rock-soil body is completed by adopting a guide pipe follow-up; (ii) a
S3: when the prestressed anchor cables A are buried, in order to enable the pile body structure of the existing slide-resistant pile to be stressed reasonably, design tension is applied to the prestressed anchor cables A in turn respectively, and the prestressed loss is considered to be over-tensioned by 10% -15%;
s4: finally, cutting off the steel strand outside the anchorage device, reserving the exposed length of 120mm, and sealing the prestressed anchor cable A by using C30 concrete with the thickness of 200mm as a cement anchor pier;
s5: according to the detection result of the steel bar detector, drilling an anchor rope preformed hole B for embedding the prestressed anchor rope B by using a concrete drilling and core-taking machine at the central axis line of the front side of the pile body, wherein the distance between the cantilever section of the pile body and the top of the pile top is not less than 300 mm;
s6: when the prestressed anchor cables B are buried, in order to enable the pile body structure of the existing slide-resistant pile to be stressed reasonably, design tension is applied to the prestressed anchor cables B in turn respectively, and the prestressed loss is considered to be over-tensioned by 10% -25%;
s7: finally, cutting off the steel strand outside the anchorage device, reserving the exposed length of 120mm, and sealing the prestressed anchor cable B by using C30 concrete with the thickness of 200mm as a cement anchor pier;
s8: after the construction of adding the prestressed anchor cable A and the prestressed anchor cable B on the existing slide-resistant pile body is completed, the residual soil body in front of the pile body is excavated according to the road expansion requirement, and the protective body of the front pile or the empty surface between piles is made in time.
Further, the front pile or space face protection body comprises a retaining wall, an inter-pile retaining plate or an inter-pile soil nailing wall which is arranged in front of the piles or between the piles.
Compared with the prior art, the invention has the following advantages and beneficial effects:
1. the invention provides a combined anti-sliding structure with an existing pile additionally provided with a prestressed anchor cable and a construction method, and effectively solves the problems that the anchoring depth of the existing anti-sliding pile is insufficient after the front slope foot of the pile body of the existing anti-sliding pile is excavated, and the bending strength and the anti-sliding force of the existing anti-sliding pile are insufficient; meanwhile, anchor cables are additionally arranged on the existing anti-slide piles for construction, so that the disturbance on the existing landslide is small, and the danger of secondary sliding in the construction period can be effectively reduced.
2. The invention provides a combined anti-sliding structure with prestressed anchor cables added to existing piles and a construction method, which fully play the anti-sliding function of the existing anti-sliding piles relative to other structures, reduce temporary support measures for slope toe expanding excavation, greatly save engineering investment, have the characteristics of simple construction, safety, rapidness, small interference on existing road operation guarantee and the like, and have wide popularization and application prospects.
Drawings
The accompanying drawings, which are included to provide a further understanding of the embodiments of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principles of the invention. In the drawings:
FIG. 1 is a schematic cross-sectional view of the invention for treating landslide along a road by using embedded anti-slide piles.
FIG. 2 is a schematic cross-sectional view of the road of the present invention for landslide control by the present invention.
Fig. 3 is a top view of the existing pile with the prestressed anchor cable added.
Fig. 4 is a front view of the existing pile with the prestressed anchor cable.
FIG. 5 is a schematic view of a novel fastening head for adding a prestressed anchor cable to an existing pile.
Reference numbers and corresponding part names:
10-existing slide-resistant pile body; 11-distribution ribs; 12-a stirrup; 13-bending-resistant reinforcing steel bars; 14-tension side (pile body back side); 15a-a central axis; 15B-B-B central axis; 16-central axis of front side of pile body; 17 a-anchor cable preformed hole A; 17 b-anchor cable preformed hole A; 18 a-anchor cable preformed hole B; 18B-anchor cable preformed holes B; 19 a-pile body cantilever section; 19 b-pile body embedding and fixing section; 20 a-a prestressed anchor cable A; 20 b-a prestressed anchor cable A; 21 a-free segment a; 22 a-anchor segment a; 21 b-free segment a; 22 b-anchor segment a; l1-spacing A; l2-eccentricity A; 30 a-a prestressed anchor cable B; 30B-prestressed anchorage cable B(ii) a 31 a-free segment B; 32 a-anchor segment B; 31B-free segment B; 32B-anchor segment B; l3-spacing B; 40-an anchor device; 41-steel strand wires; 42-a catheter; 43-steel backing plate; 44-cement anchor piers; 45-plastic gaskets; 50-excavating a protective measure on an empty surface; 60-a sliding surface; 70-horizontal plane; thetaa-an anchoring angle; thetab-an anchoring angle.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to examples and accompanying drawings, and the exemplary embodiments and descriptions thereof are only used for explaining the present invention and are not meant to limit the present invention.
In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, it will be apparent to one of ordinary skill in the art that: it is not necessary to employ these specific details to practice the present invention. In other instances, well-known structures, circuits, materials, or methods have not been described in detail so as not to obscure the present invention.
Throughout the specification, reference to "one embodiment," "an embodiment," "one example," or "an example" means: the particular features, structures, or characteristics described in connection with the embodiment or example are included in at least one embodiment of the invention. Thus, the appearances of the phrases "one embodiment," "an embodiment," "one example" or "an example" in various places throughout this specification are not necessarily all referring to the same embodiment or example. Furthermore, the particular features, structures, or characteristics may be combined in any suitable combination and/or sub-combination in one or more embodiments or examples. Further, those of ordinary skill in the art will appreciate that the illustrations provided herein are for illustrative purposes and are not necessarily drawn to scale. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.
[ examples ] A method for producing a compound
As shown in fig. 1, the method is applied to solve the problem of engineering instability caused by increased landslide thrust, reduced anchoring length and insufficient bending strength (anti-slip force) borne by the existing slide-resistant pile when the rock-soil mass in front of the pile (slope toe) is excavated again due to later engineering construction (such as road extension, upgrading and reconstruction and the like) after the existing slide-resistant pile is adopted to treat landslide engineering.
As shown in FIG. 2, the scheme is a novel combined anti-slide structure which is used for reinforcing and improving the existing anti-slide pile and optimizing the structural stress by drilling the cantilever section of the existing anti-slide pile and additionally arranging a vertical prestressed anchor cable A and a plurality of rows of diagonal prestressed anchor cables B; the method aims to optimize the pile body internal force distribution of the existing pile, provide enough anchoring force for the existing pile, and share a part of landslide thrust so as to reinforce and manage the engineering instability caused by slope toe excavation.
As shown in fig. 2, 3, 4 and 5, a combined anti-sliding structure with an existing pile additionally provided with a prestressed anchor cable comprises an existing anti-sliding pile body 10, wherein the pile body 10 is divided into an embedded section 19b and a cantilever section 19a, and the embedded section 19b is embedded in a stable rock-soil body below a sliding surface 60; a vertical prestressed anchor cable A20a is arranged on the top of the cantilever section 19a of the pile body 10, the upper end of the vertical prestressed anchor cable A20a is connected with the top of the cantilever section 19a of the pile body 10, and the lower end of the vertical prestressed anchor cable A20 is vertically penetrated downwards from the top of the cantilever section 19a of the pile body 10 through the bottom of the embedded section 19b of the pile body 10 and extends along the direction of the embedded section 19 b; in the embodiment, two prestressed anchor cables a are provided, namely a prestressed anchor cable a20a and a prestressed anchor cable a20b, and a plurality of prestressed anchor cables a can be provided and uniformly distributed in the scheme; the prestress applied by the prestressed anchor cable a20a provides enough anchoring force for the existing slide-resistant pile body 10, and improves the stress mode of the existing slide-resistant pile body 10.
The setting position of the prestressed anchor cable A20a is as follows: according to the structural stress of the pile body 10 after the soil body before the pile of the existing slide-resistant pile body 10 is excavated, the landslide thrust, the pile length (the cantilever section 19a and the embedded section 19b), the pile section size, the pile body steel bar arrangement, the anchoring force of the existing slide-resistant pile body 10 and the like are considered; meanwhile, the eccentricity AL2 of the prestressed anchor cable A, namely the distance between the hole distribution position 17a and the central axis 15b, the distance AL1 of the prestressed anchor cable A, namely the hole distribution positions (17a and 17b), the length of the free section 21a of the anchor cable, the length of the anchoring section 22a, the number of the steel strands 41, the designed prestress value of the anchor cable and the like are reasonably set.
The cantilever section 19a of the pile body 10 is also provided with a cable-stayed prestressed anchor cable B30a, the lower end of the cable-stayed prestressed anchor cable B30a is anchored in the stable rock-soil body behind the sliding surface 60, the upper end of the cable-stayed prestressed anchor cable B30 is connected with the cantilever section 19a of the pile body 10, and the cable-stayed prestressed anchor cable B30a forms an included angle horizontal plane with the horizontal plane 70; in the embodiment, two prestressed anchor cables B are provided, namely a prestressed anchor cable B30a and a prestressed anchor cable B30B, and a plurality of prestressed anchor cables B can be provided, and the space and the anchoring angle of the prestressed anchor cables B are reasonably set; the maximum stress bending moment of the existing slide-resistant pile body 10 is reduced by applying prestress to the prestressed anchor cable B18a, and the internal force distribution of the pile body 10 is optimized.
The setting position of the prestressed anchor cable B18a is as follows: according to the structural stress of the pile body 10 after the excavation of the soil body in front of the pile of the existing slide-resistant pile body 10, the landslide thrust, the pile length (the cantilever section 19a and the embedded section 19b), the pile section size, the pile body steel bar arrangement, the anchoring force of a pre-stressed anchor cable A20a and the like are considered; meanwhile, the distance BL3 between the prestressed anchor cable B18a and the prestressed anchor cable B30B, namely the hole distribution positions (18a and 18B) and the anchor angle B (theta) are reasonably seta、θa) The length of the free section 31a of the prestressed anchor rope B18a, the length of the anchor section 32a, the number of the strands 41, the designed prestress value of the prestressed anchor rope B18a, and the like.
Furthermore, distribution ribs 11 and stirrups 12 are arranged in the pile body 10, and bending-resistant reinforcing steel bars 13 are arranged on the tension side of the pile body 10;
drilling anchor rope preformed holes A17a for placing vertical prestressed anchor ropes A20a at symmetrical positions of an A-A central axis 15a of a cantilever section 19a of the pile body 10 outside a protective layer of a bending-resistant reinforcing steel bar 13 at the tension side of the pile body 10; the distance A between the prestressed anchor cable A20a and the prestressed anchor cable A20b is L1, and the eccentricity A between the prestressed anchor cable A20a and the prestressed anchor cable A20b and the central axis 15b is L2; vertical prestress can be applied through the prestressed anchor cable A20a, the vertical anchoring force of the existing slide-resistant pile body 10 is effectively enhanced, and the stress mode of the existing slide-resistant pile body 10 is improved.
Further, the drill is arranged at the central axis 16 of the front side of the pile body at the position where the cantilever section 19a of the pile body 10 is not smaller than 300mm from the top of the pile topArranging a stay cable anchor cable preformed hole B18a for placing a stay cable prestressed anchor cable B30 a; wherein the prestressed anchorage cable B30a forms an included angle theta with the horizontal plane 70aIs an anchoring angle; the angle theta formed by the prestressed anchor cable B30B and the horizontal plane 70bIs an anchoring angle; by applying oblique prestress to the pre-stressed anchor cable B30a and the pre-stressed anchor cable B30B, the bending strength of the existing slide-resistant pile body 10 is effectively enhanced, and the internal force distribution of the existing slide-resistant pile body 10 is optimized; meanwhile, the prestressed anchor cable A20a and the prestressed anchor cable B30a are additionally arranged on the existing slide-resistant pile body 10, so that the existing slide-resistant pile body 10 can be enhanced, improved and optimized in structural stress, the slide-resistant effect of the existing slide-resistant pile body 10 is fully exerted, temporary support measures for slope toe expanding excavation are reduced, and the engineering investment is greatly saved.
Further, one or more anchor cable preformed holes a17a are arranged on the top of the cantilever section 19a of the pile body 10; the vertical prestressed anchor cable A20a consists of a fastening head, a free section and an anchoring section, wherein the fastening head consists of a cement anchor pier 44, a steel backing plate 43 and an anchorage device 40; and a plastic gasket 45 is arranged between the cement anchor pier 44 and the pile body 10.
Further, one or more anchor cable preformed holes B18a are arranged on the central axis 16 of the front side of the pile body at the position, which is not smaller than 300mm away from the top of the pile top, of the cantilever section 19a of the pile body 10; the cable-stayed prestressed anchor cable B30a consists of a fastening head, a free section and an anchoring section, wherein the fastening head consists of a cement anchor pier 44, a steel backing plate 43 and an anchorage device 40; and a plastic gasket 45 is arranged between the cement anchor pier 44 and the pile body 10.
Further, the plastic gasket 45 is a rubber gasket or a nylon gasket with the thickness of 30mm, and the boundary size of the plastic gasket 45 is 50mm larger than that of the cement anchor block 44.
In the existing prestressed anchor cable construction, because the existing anti-slide pile body 10 is constructed for years, the concrete on the surface layer part of the pile body 10 may be corroded, aged and uneven, when the prestressed anchor cable is added in the later period, in order to prevent the cement anchor pier 44 from generating rigid contact with the pile body 10, the surface concrete is cracked after the prestress of the prestressed anchor cable A20a or the prestressed anchor cable B30a is applied, so that the anchor cable generates prestress loss and the structure safety is influenced; therefore, in the scheme, a rubber gasket or a nylon gasket with the thickness of 30mm is independently arranged between the pile body 10 of the existing slide-resistant pile and the cement anchor pier 44, and the boundary size of the rubber gasket or the nylon gasket is 50mm larger than that of the cement anchor pier 44; the structure can provide enough deformation space for the concrete contact surface of the existing slide-resistant pile body 10 when being pressed, so that the slide-resistant pile body 10 is stressed uniformly and deforms and is coordinated, the surface concrete of the existing slide-resistant pile body 10 is protected from cracking and damage, a steel bar protective layer of the slide-resistant pile body 10 is protected, the prestress loss of an anchor rope is reduced, and the structural safety degree is improved.
Furthermore, the prestressed anchor cable A20a and the prestressed anchor cable B30a both adopt 4-8 strands of steel stranded wires 41, and the same anchoring tension is designed; the prestressed anchor cable A20a is divided into an anchoring section A22 a and a free section A21 a; the anchoring section A22 a is an anchoring section anchored in a stable rock-soil body below the sliding surface 60, the free section A21 a is the distance length from the top of the prestressed anchor cable A20a to the pile bottom of the existing slide-resistant pile body 10, which is plus 500mm, namely the free section A21 a of the prestressed anchor cable A20a extends into the pile bottom of the existing slide-resistant pile body 10 and is not less than 500 mm; the prestressed anchor cable B30a is divided into an anchoring section B32 a and a free section B31 a, wherein the anchoring section B32 a is an anchoring section anchored in a stable rock-soil body behind the sliding surface 60; the free section B31 a is the distance length +1000mm from the top of the prestressed anchor cable B30a to the sliding surface 60, namely the distance that the free section B31 a of the prestressed anchor cable B30a extends into the sliding surface 60 is not less than 1000 mm; the prestressed anchor cable B30a and the prestressed anchor cable B30B keep a certain distance BL3 and an anchor angle thetaaAnd an anchor angle thetabHolding thetaa≤θbTo reduce the group anchor effect.
Wherein, the distance between L3 is preferably 3-6 m, and the minimum distance is not less than 1.5 m. The included angle between the prestressed anchor cable B30a and the horizontal plane 70 is preferably lower, should not be greater than 45 degrees, and is preferably 15-30 degrees.
The working principle of the invention comprises the following steps:
s1: collecting a structural design drawing and a completion drawing of an existing slide-resistant pile body 10 in a construction stage, wherein the two structural design drawings and the completion drawing in the construction stage include but are not limited to collection of drawings of a pile body structure, design reinforcement, steel bar arrangement and the like; detecting the structure and the steel bars of the existing slide-resistant pile body 10 by using a steel bar detector through an electromagnetic induction method, wherein the positions of the steel bars, the thickness of a protective layer and the diameter of the steel bars in a concrete structure or a component are detected, or the number, the trend, the distribution and the like of the detected steel bars are detected;
s2: according to the detection result of the steel bar detector, outside the protective layer of the bending-resistant steel bar 13 on the tension side 14 of the pile body 10, drilling an anchor rope preformed hole A17a for embedding the prestressed anchor rope A20a by using a concrete drilling and core-taking machine according to the symmetrical position of an A-A central axis 15a at the top of a cantilever section 19b of the pile body 10, wherein the drilling position should avoid the steel bar position (including the concrete protective layer), and the drilling position needs to be symmetrical and reasonably set the drilling eccentricity, the spacing, the aperture size and the like; after the anchor cable preformed hole A17a is drilled, the guide pipe 42 is adopted to follow up to complete the subsequent drilling in rock and soil mass;
s3: when the prestressed anchor cable A20a is buried, in order to enable the pile body 10 structure of the existing slide-resistant pile to be stressed reasonably, total tension is respectively and alternately applied to the prestressed anchor cable A20a (the total tension is design tension and anchor cable prestress loss over-tension), wherein the total tension is respectively and alternately applied to the prestressed anchor cable A20a according to 50%, 70% and 100% (a free section is positioned in the pile body, and prestress loss over-tension is considered to be 10% -15%);
s4: finally, cutting off the steel strand 41 outside the anchorage device 40, reserving the exposed length of 120mm, and sealing the prestressed anchor cable A20a by using C30 concrete with the thickness of 200mm as a cement anchor pier 44;
s5: according to the detection result of the steel bar detector, drilling and placing an anchor rope preformed hole B18a drilled by a concrete drilling and core-taking machine and used for embedding the prestressed anchor rope B30a at the central axis 16 of the front side of the pile body at the position, not smaller than 300mm away from the top of the pile top, of the cantilever section 19a of the pile body 10, wherein the drilling position should avoid the position of the steel bar (including a concrete protective layer), and the drilling interval, the anchoring angle, the aperture size and the like are reasonably set;
s6: similarly, when the prestressed anchor cable B30a is buried, in order to enable the pile body 10 structure of the existing slide-resistant pile to be stressed reasonably, total tension is applied to the prestressed anchor cable B30a in turn, wherein the total tension is applied to the prestressed anchor cable B30a in turn according to 50%, 70% and 100% respectively, (when the free section is a rock stratum, the prestressed loss is considered to be over-tensioned by 10% -15%, and when the free section is a soil stratum, the prestressed loss is considered to be over-tensioned by 10% -20%);
s7: finally, cutting off the steel strand 41 outside the anchorage device 40, reserving the exposed length of 120mm, and sealing the prestressed anchor cable B30a by using C30 concrete with the thickness of 200mm as a cement anchor pier 44;
s8: after the construction of adding the prestressed anchor cable A20a and the prestressed anchor cable B30a on the existing slide-resistant pile body 10 is completed, the residual soil body in front of the pile body is excavated according to the road extension requirement, and the pre-pile or inter-pile empty face protection body 50 is made in time.
Further, the pre-pile or inter-pile face shield 50 includes a retaining wall, an inter-pile retaining plate, or an inter-pile soil nailing wall provided in front of or between the piles.
The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are merely exemplary embodiments of the present invention, and are not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.
Claims (9)
1. A combined anti-sliding structure with an existing pile additionally provided with a prestressed anchor cable comprises an existing anti-sliding pile body (10), wherein the pile body (10) is divided into a cantilever section (19a) and an embedded section (19b), and the embedded section (19b) is embedded and fixed in a stable rock-soil body below a sliding surface (60);
the pile is characterized in that a vertical prestressed anchor cable A (20a) is arranged on the top of the cantilever section (19a) of the pile body (10), the upper end of the vertical prestressed anchor cable A (20a) is connected with the top of the cantilever section (19a) of the pile body (10), and the lower end of the vertical prestressed anchor cable A (20a) vertically penetrates through the bottom of the embedded section (19b) of the pile body (10) from the top of the cantilever section (19a) of the pile body (10) downwards and extends along the direction of the embedded section (19 b);
and a cable-stayed prestressed anchor cable B (30a) is also arranged on the cantilever section (19a) of the pile body (10), the lower end of the cable-stayed prestressed anchor cable B (30a) is anchored in the stable rock-soil body behind the sliding surface (60), the upper end of the cable-stayed prestressed anchor cable B (30a) is connected with the cantilever section (19a) of the pile body (10), and an included angle theta is formed between the cable-stayed prestressed anchor cable B (30a) and the horizontal plane (70).
2. The combined anti-sliding structure of the existing pile added with the prestressed anchor cable according to claim 1, characterized in that a distribution rib (11) and a stirrup (12) are arranged in the pile body (10), and a bending-resistant reinforcing steel bar (13) is arranged on the tension side (14) of the pile body (10);
and drilling anchor rope preformed holes A (17a) for placing the vertical prestressed anchor ropes A (20a) at the symmetrical positions of the central axis (15a) of the cantilever section (19a) of the pile body (10) outside the protective layer of the bending-resistant reinforcing steel bars (13) at the tension side (14) of the pile body (10).
3. The combined structure of an existing pile with an additional prestressed anchor cable of claim 2 is characterized in that one or more anchor cable preformed holes A (17a) are arranged on the top of the cantilever section (19a) of the pile body (10);
the vertical prestressed anchor cable A (20a) consists of a fastening head, a free section and an anchoring section, wherein the fastening head consists of a cement anchor pier (44), a steel base plate (43) and an anchorage device (40);
and a plastic gasket (45) is arranged between the cement anchor pier (44) and the pile body (10).
4. The combined anti-sliding structure of the existing pile added with the prestressed anchor cable according to claim 1, wherein a stay anchor cable reserved hole B (18a) for placing the stay prestressed anchor cable B (30a) is drilled at the central axis (16) of the front side of the pile body at the position where the distance between the cantilever section (19a) of the pile body (10) and the top of the pile top is not less than 300 mm.
5. The combined anti-sliding structure of the existing pile with the additional pre-stressed anchor cables according to claim 4, characterized in that one or more anchor cable reserved holes B (18a) are arranged at the central axis (16) of the front side of the pile body, which is located at a position where the distance between the cantilever section (19a) of the pile body (10) and the top of the pile top is not less than 300 mm;
the cable-stayed prestressed anchor cable B (30a) consists of a fastening head, a free section and an anchoring section, wherein the fastening head consists of a cement anchor pier (44), a steel backing plate (43) and an anchorage device (40);
and a plastic gasket (45) is arranged between the cement anchor pier (44) and the pile body (10).
6. The combined antiskid structure of the prestressed anchor cable added to the existing pile according to any one of claims 3 or 5, wherein the plastic gasket (45) is a rubber gasket or a nylon gasket with a layer thickness of 30mm, and the boundary size of the plastic gasket (45) is 50mm larger than that of the cement anchor block (44).
7. The combined anti-sliding structure of the pre-stressed anchor cable added to the existing pile according to claim 1, wherein the pre-stressed anchor cable A (20a) and the pre-stressed anchor cable B (30a) are each 4-8 strands of steel strands (41);
the prestressed anchor cable A (20a) is divided into an anchoring section A (22a) and a free section A (21 a); the anchoring section A (22a) is an anchoring section anchored in a stable rock-soil body below the pile body (10), and the free section A (21a) is the distance length from the top of a prestressed anchor cable A (20a) to the pile bottom of the pile body (10) plus 500 mm;
the prestressed anchor cable B (30a) is divided into an anchoring section B (32a) and a free section B (31a), wherein the anchoring section B (32a) is an anchoring section anchored in a stable rock-soil body behind the sliding surface (60), and the free section B (31a) is the distance length +1000mm from the top of the prestressed anchor cable B (30a) to the sliding surface (60).
8. A construction method of a combined anti-sliding structure with an existing pile additionally provided with a prestressed anchor cable is characterized by comprising the following steps:
s1: collecting a structural design drawing and an as built drawing of the existing slide-resistant pile body (10) in a construction stage; a reinforcing steel bar detector is adopted to detect the structure and the reinforcing steel bars of the existing slide-resistant pile body (10) by an electromagnetic induction method;
s2: according to the detection result of the steel bar detector, drilling an anchor cable preformed hole A (17a) for embedding the prestressed anchor cable A (20a) by adopting a concrete drilling and core-drilling machine at the symmetrical position of a central axis (15a) at the top of a cantilever section (19a) of the pile body (10) outside a protective layer of a bending-resistant steel bar (13) at the tension side (14) of the pile body (10); after the anchor cable preformed hole A (17a) is drilled, a guide pipe (42) is adopted to follow up to complete the subsequent drilling in the rock-soil body;
s3: when the prestressed anchor cable A (20a) is buried, in order to enable the pile body (10) structure of the existing slide-resistant pile to be stressed reasonably, design tension is applied to the prestressed anchor cable A (20a) in turn respectively, and 10% -15% of prestressed loss overstretching is considered;
s4: finally, cutting off the steel strand (41) outside the anchorage device (40), reserving the exposed length of 120mm, and using C30 concrete with the thickness of 200mm as a cement anchor pier (44) to seal the prestressed anchor cable A (20 a);
s5: according to the detection result of the steel bar detector, drilling an anchor rope preformed hole B (18a) for embedding the prestressed anchor rope B (30a) by drilling a concrete drilling core-drilling machine at a position, which is not smaller than 300mm away from the top of the pile top, of a cantilever section (19a) of the pile body (10) from a central axis (16) on the front side of the pile body;
s6: when the prestressed anchor cables B (30a) are buried, in order to enable the pile body (10) of the existing slide-resistant pile to be reasonably stressed, design tension is respectively and alternately applied to the prestressed anchor cables B (30a), and the prestressed loss is considered to be over-tensioned by 10% -20%;
s7: finally, cutting off the steel strand (41) outside the anchorage device (40), reserving the exposed length of 120mm, and using C30 concrete with the thickness of 200mm as a cement anchor pier (44) to seal the prestressed anchor cable B (30 a);
s8: after the construction of adding the prestressed anchor cable A (20a) and the prestressed anchor cable B (30a) on the existing slide-resistant pile body (10) is completed, the residual soil body in front of the pile body is excavated according to the road extension requirement, and the pre-pile or inter-pile empty face protection body (50) is made in time.
9. The method as claimed in claim 8, wherein the pre-pile or inter-pile face shield (50) comprises a retaining wall, an inter-pile retaining plate or an inter-pile nailing wall disposed in front of or between the piles.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010807203.7A CN111827316A (en) | 2020-08-12 | 2020-08-12 | Combined anti-sliding structure with prestressed anchor cables additionally arranged on existing pile and construction method |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202010807203.7A CN111827316A (en) | 2020-08-12 | 2020-08-12 | Combined anti-sliding structure with prestressed anchor cables additionally arranged on existing pile and construction method |
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| CN111827316A true CN111827316A (en) | 2020-10-27 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114482118A (en) * | 2022-01-17 | 2022-05-13 | 兰州铁道设计院有限公司 | Method for realizing width of embankment side by existing-newly built combined cantilever type retaining wall |
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2020
- 2020-08-12 CN CN202010807203.7A patent/CN111827316A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114482118A (en) * | 2022-01-17 | 2022-05-13 | 兰州铁道设计院有限公司 | Method for realizing width of embankment side by existing-newly built combined cantilever type retaining wall |
| CN114482118B (en) * | 2022-01-17 | 2024-03-26 | 兰州铁道设计院有限公司 | Method for realizing embankment width by existing-newly-built combined cantilever retaining wall |
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