CN111997066A

CN111997066A - Manufacturing and construction method of assembled prestressed anchor cable frame beam for slope reinforcement

Info

Publication number: CN111997066A
Application number: CN202010828008.2A
Authority: CN
Inventors: 魏少伟; 张新尚; 蔡德钩; 秦川; 姚建平; 施秀山; 刘力; 李松; 孙宣; 杨海洋; 曹渊东
Original assignee: Honghe Mengping Expressway Investment Development Co ltd; China Academy of Railway Sciences Corp Ltd CARS; Railway Engineering Research Institute of CARS; Beijing Tieke Special Engineering Technology Co Ltd
Current assignee: China Academy of Railway Sciences Corp Ltd CARS; Railway Engineering Research Institute of CARS; Beijing Tieke Special Engineering Technology Co Ltd
Priority date: 2020-08-17
Filing date: 2020-08-17
Publication date: 2020-11-27

Abstract

The invention relates to a method for manufacturing and constructing an assembled prestressed anchor cable frame beam for slope reinforcement, which can improve the section performance of the beam and bear larger anchoring force, and solves the defects that the traditional cast-in-place reinforced concrete lattice beam is likely to be pulled apart at the midspan position when the anchoring force of an anchor cable is larger, so that a component is easy to corrode a reinforcing steel bar in a precipitation frequent area and the rigidity is reduced; the mechanical property is greatly improved. The thickness of the beam body can be reduced or stressed steel bars can be reduced, and the material utilization rate is improved, so that the beam is more economical. The prestressed anchor cable frame beam is formed by mutually splicing a plurality of precast beam body units, the beam body units are simpler to manufacture, lighter to mount and easy to adjust during mounting, and the construction period is greatly shortened.

Description

Manufacturing and construction method of assembled prestressed anchor cable frame beam for slope reinforcement

Technical Field

The invention relates to the technical field of traffic transportation engineering, in particular to a manufacturing and construction method of an assembled prestressed anchor cable frame beam for slope reinforcement.

Background

China is a multi-mountain country, plateaus, hills and mountains account for about 70% of land area in China, and a large amount of landslides, collapses and debris flow disasters occur every year. In addition, when a ground is leveled in a civil engineering, the situation of large excavation, slope release and the like of a mountain is often encountered, the peripheral mountain needs to be cut, and the original balance is damaged by cutting operation. In order to ensure the safety of the side slope and the environment thereof, support, reinforcement and protection measures must be taken for the side slope.

The slope anchor rod (cable) lattice reinforcing technology has the obvious advantages of flexible arrangement, various lattice forms, convenient section adjustment, close adhesion with a slope surface, capability of following the slope and the like, and is a commonly used method in slope reinforcement. However, in the prior art, when the anchor rod (cable) lattice beam is used to reinforce the side slope, the construction method of the concrete lattice beam is usually a cast-in-place method, the construction of the frame beam steel bar and the formwork and the casting and maintenance of the concrete are all completed on the site, and the following disadvantages mainly exist:

(1) when the cast-in-place lattice beam is manufactured, the required construction period is longer due to more processes of side slope grooving, template processing, reinforcement binding, concrete pouring, maintenance and the like and low overall mechanization degree in the construction process;

(2) the cast-in-place concrete lattice beam has more processes and more influence factors, so that the quality of the cast-in-place concrete lattice beam cannot be guaranteed;

(3) the stretching of the prestressed anchor rod (cable) can be carried out only after the external anchor structure reaches the design strength, and the whole construction period is often seriously prolonged due to the maintenance of the external anchor structure;

(4) when the traditional cast-in-place reinforced concrete lattice beam meets the condition that the anchoring force of an anchor rope is large, the traditional cast-in-place reinforced concrete lattice beam is likely to be pulled apart at the midspan position to cause the rigidity of a component to be reduced, and the overall stability is influenced.

Disclosure of Invention

Aiming at the problems in the prior art, the invention provides a method for manufacturing and constructing an assembled prestressed anchor cable frame beam for slope reinforcement, which has the characteristics of simplifying construction steps, shortening construction period, reducing construction risk, realizing standardized management production, ensuring product quality, being economical, practical and environment-friendly. The invention can replace the existing cast-in-place anchor rod (cable) lattice beam to carry out slope reinforcement, has outstanding advantages in slope emergency reinforcement, and is also suitable for carrying out slope rapid reinforcement construction in reconstruction and extension of highways.

In order to achieve the purpose, the invention provides a method for manufacturing an assembled prestressed anchor cable frame beam for slope reinforcement, which comprises the following steps:

(1) determining a prefabricated part unit of a prestressed anchor cable frame beam, wherein the prefabricated part unit comprises a cross beam and a linear beam;

(2) manufacturing sizing side molds with matched sizes according to the size parameters of the cross beam and the straight beam respectively, and building a bottom mold;

(3) preparing a steel reinforcement framework according to the sizes of the cross beam and the straight beam and installing the steel reinforcement framework to the bottom die;

(4) mounting the cross beam shaping side mold to a bottom mold of the cross beam, and pouring concrete in layers; after the preset strength is reached, the shaping side die is dismantled, and concrete is maintained; mounting the straight beam shaping side mold to a bottom mold of the straight beam, and pouring concrete in a layered manner; after the preset strength is reached, the shaping side die is dismantled, and concrete is maintained;

(5) respectively tensioning the cross beam and the straight beam according to a set prestress value;

(6) respectively sealing the cross beam and the straight beam;

(7) and hoisting the prefabricated part units on the treated slope surface, and stretching, grouting and sealing the anchor cables of the prefabricated part units to form the prestressed anchor cable frame beam.

Furthermore, the shaping side die adopts a steel template or an aluminum template, and is subjected to anticorrosion and antirust treatment, load test and pre-assembly before leaving a factory.

Furthermore, the bottom die is built by red bricks, firstly, measurement, setting and positioning are carried out, then, foundation leveling is carried out, the bricks are built, and then, mortar is adopted for plastering.

Further, preparing the steel reinforcement cage according to the unit size of the prefabricated parts includes: screening the steel bars, selecting the steel bars and the steel strands meeting the requirements, blanking, welding the steel bar framework, installing the steel strands, and checking and accepting the installation quality of the steel bars and the steel strands;

the design side form installation of cross roof beam, word roof beam to the die block includes: the steel bars are bound by 20-22 # iron wires in a staggered manner point by point in a splayed manner, and the binding wires cannot extend into the concrete; the C40 concrete cushion blocks are arranged between the steel bars and the red brick bottom die, the C40 concrete cushion blocks are arranged in a quincunx shape, each square meter is not less than 4, the steel bar joints are arranged in a dispersed mode, and the same cross-sectional area is not more than 25% of the total cross-sectional area of the steel bars.

Further, still include the installation sensor, specifically include:

the steel strand stress meter is welded on a main rib of the steel reinforcement framework, a phi 80mm PVC pipe is sleeved outside the steel strand stress meter, and two ends of the PVC pipe are blocked by adopting a polyurethane foaming agent;

the steel bar stress meter is fixed on a main bar of the steel bar framework by adopting a butt-welding method, a lead is protected in the welding process, and the steel bar stress meter is physically cooled by using a wet towel;

the concrete surface stress meter is arranged on the concrete surface corresponding to the main reinforcement of the steel bar framework when the strength reaches 30MP after concrete is poured in a layered mode, and drilling and installation are carried out by adopting an electric drill;

the method comprises the following steps that (1) a soil pressure box is buried under a longitudinal beam and a cross beam of a steel bar framework, a round pit with the depth of 4cm is firstly dug at a position where the soil pressure box needs to be buried, fine sand is used for filling and leveling, and then the soil pressure box is fixed in place; the working surface of the soil pressure cell in place is flush with the slope surface so as to accurately measure the soil pressure and ensure that the pressure direction is consistent with the axial direction of the pressure cell.

Further, the layered casting of concrete includes:

mixing intensively in a mixing station, transporting a concrete transport vehicle to the site, and pouring in a chute mold-entering mode; concrete is poured in layers, the concrete is tamped in layers, a vibrator is vertically inserted into the concrete, a vibrating rod is inserted into the concrete quickly and slowly, the vibrating time of each vibrating point is 20-30 seconds, the vibrating rod is inserted into the lower layer by 5-10cm, the moving distance of the vibrating rod cannot exceed 1.5 times of the effective vibrating radius, the vibrating rod is slowly lifted out while vibrating until no bubbles emerge, and the vibrating rod is prevented from colliding a template, a reinforcing steel bar and other embedded parts; vibrating each vibration part until the concrete is compact, wherein the compact mark is that the concrete stops sinking, bubbles do not emerge any more, the surface is flat and slurry, and the surface of the concrete cannot be subjected to sand casting caused by excessive vibration; before final setting after the press polishing of the concrete tamping surface, the concrete tamping surface cannot be disturbed, and the interruption time is not longer than the initial setting time of the concrete on the front layer.

Further, the layered casting concrete further comprises:

and manufacturing a concrete sample, carrying out strength pressure test, judging whether the requirement is met, carrying out prestress tensioning operation if the requirement is met, searching the reason if the requirement is not met, and treating the concrete sample as a waste product.

Further, curing the concrete includes: spraying curing agent after the concrete is initially set, wherein the using amount of the curing agent is 10 square meters per kg, covering plastic cloth on the outer surface of the concrete to prevent moisture from evaporating after the curing agent is sprayed for two hours, and the curing time is not less than 14 days; and when the strength of the concrete reaches 2.5MP, the shaping side die is disassembled.

Further, tensioning according to a set prestress value comprises the following steps: firstly, stretching to 10% of a set prestress value, and recording the concrete elongation value; tensioning to 20% of the set prestress value, and recording the concrete elongation value; finally, stretching to a set prestress value, and recording the elongation value of the concrete; the difference between the sum of the elongation values of the two ends and the design value is not more than +/-6%, and if the difference exceeds the range, the reason is found out.

Further, the prefabricated unit sealing anchor comprises:

the distance between the cutting position of the steel strand bundle cutting steel strand and the outer end of the anchorage device is not less than 30mm by adopting a grinding wheel cutting machine; before sealing, chiseling an anchor recess, wherein the chiseling area is not less than 90%, the depth is not less than 5mm, no mortar exists on the surface, the anchor recess needs to be cleaned after chiseling, and the anchor recess is cleaned with water for wetting before sealing and pouring concrete; the anchor sealing concrete is tamped compactly without honeycomb pitted surface, the plastering is press polished, and the platform between the concrete surface and the end surface of the beam after the anchor sealing is not more than 2 mm; and (4) carrying out moisture preservation and heat preservation maintenance on the anchor sealing concrete, carrying out waterproof treatment, and brushing waterproof materials on the outer side of the anchor groove.

Furthermore, the prefabricated part unit is a cross-shaped two-or-line beam and comprises a middle main body and two or four extending arms which uniformly extend outwards along the main body, and the length of each extending arm is set according to requirements; the section of the extension arm is rectangular; the middle main body is of a cubic structure.

Further, tensioning the prefabricated unit anchor cable comprises:

for a secondary slope, the initial anchoring value of the tensioned anchor cables with the slope ratio of 1:1 is 0.26-0.35 times of anchoring force, and for a primary slope, the initial anchoring value of the tensioned anchor cables with the slope ratio of 1:0.75 is 0.48-0.6 times of anchoring force.

Further, the prefabricated part unit grouting comprises: grouting a gap between the prefabricated member unit and the slope surface for plugging, arranging exhaust holes at a vertical distance of 1m, and maintaining for at least 7 days; the grouting material comprises the following components in percentage by weight: cement, water glass: firstly, adding 80-90% of water in a stirring barrel, starting a handheld stirrer, uniformly adding the expanding agent while stirring, then uniformly adding all cement, adding all powder and then stirring for 2 min; then adding the rest water, and continuously stirring for 2 min; after the mixture is uniformly stirred, a machine-out fluidity test is carried out on site, and the machine-out fluidity range meets 18s +/-4 s.

The invention also provides a construction method for slope reinforcement, which comprises the following steps:

(1) the manufacturing method of the assembled prestressed anchor cable frame beam for slope reinforcement is adopted to manufacture cross beams and linear beams with required quantity; a linear beam is arranged between the two longitudinal cross beams;

(2) measuring and paying off anchor holes of the cross beam and the straight beam, processing the anchor holes, cleaning the anchor holes, and inserting anchor cables into the anchor holes;

(3) grouting anchor holes of the cross beam and the straight beam;

(4) after the cement mortar in the anchor hole reaches more than 80%, tensioning the anchor cable, and fixing the anchor cable on an anchorage device after tensioning;

(5) and (5) sealing the anchor by using the anchor head.

Further, the anchor hole measuring payoff includes: the distance between the anchor cables is 3m multiplied by 3m, the distance between the first row of anchor cables and the slope top is 2m, and the distance between the bottom row of anchor cables and the slope bottom is 2 m; the hole site error is not more than +/-50 mm.

Further, in the anchor hole machining process, a drilling machine is adopted for drilling in a rock stratum, and a follow pipe drilling hole is adopted for drilling in a stratum which is easy to collapse and drill stuck and buried; in the range that the drilling machine can not be directly operated, a scaffold rod with the diameter of 48mm is adopted to erect a platform, the platform is fixed with a slope surface by an anchor rod, and the drilling machine is lifted to the platform by a three-foot bracket; the vertical and horizontal errors of the drill holes are not more than +/-50 mm, the elevation errors are not more than +/-100 mm, the inclination angle allowable error of the drill holes is +/-1.0 degree, and the azimuth allowable error is +/-2.0 degrees; the intersection angle of the anchor rod, the anchor cable and the horizontal plane is 25 degrees; the hole diameter and the hole depth of the drill hole are not less than the design values, the deviation of the hole opening is less than or equal to +/-50 mm, and the allowable deviation of the hole depth is +200 mm.

Further, the anchor cable adopts phi^S15.24, arranging a phi 25PVC grouting pipe in the middle, and circularly arranging steel strands on the periphery; arranging an isolating ring at intervals of 2.0m, arranging a positioning sheet on the anchor cable outer sleeve to be centered after the anchor cable is inserted into the hole, and arranging a guide cap at the tail end; each anchor cable is 1.5m longer than the designed length so as to extend out of the anchorage device for tensioning;

inserting the manufactured anchor cable into the anchor hole to enable the anchor cable to be centered and 0.5cm away from the bottom of the hole; and reserving a steel strand with the length of 1.5m outside the anchor hole, wherein the carrying fulcrum is not more than 2m and the turning radius is not less than 10m when the anchor cable is laid.

Further, the anchor hole grouting adopts cement mortar, and the ratio of the mortar to the sand is 1:1, the water-cement ratio is 0.45-0.5, the grouting pressure of the anchor cable is not less than 0.5MPa, and the strength of the grouting body meets the requirement that the strength of the anchor cable is not less than 35 MPa.

Further, tensioning the anchor cable comprises: after the cement mortar in the anchor hole reaches more than 80%, tensioning the prestressed anchor cable, wherein the initial anchoring value of tensioning the second-level slope anchor cable is 0.26-0.35 times of anchoring force, and the initial anchoring value of tensioning the first-level slope anchor cable is 0.48-0.6 times of anchoring force; the applied prestress value is 1.1 times of the design value, and the elongation of the steel strand is recorded in each stage in the tensioning process; and performing additional tensioning on the 7 th day after tensioning; and during tensioning, if the difference between the actual elongation value and the theoretical value is more than +/-6%, suspending the tensioning and finding out the reason.

The technical scheme of the invention has the following beneficial technical effects:

(1) the prefabricated lattice beam is a prestressed concrete lattice beam, so that the section performance of the beam can be improved, the beam can bear larger anchoring force, and the defects that a steel bar of a member is easy to corrode and the rigidity is reduced in a region with frequent rainfall caused by the fact that the traditional cast-in-place reinforced concrete lattice beam is pulled to crack at a midspan position when the anchoring force of an anchor rope is larger are overcome; the mechanical property is greatly improved.

(2) The precast prestressed concrete lattice beam can also reduce the thickness of the beam body or reduce stressed steel bars, and improve the utilization rate of materials, thereby being more economic.

(3) The prefabricated lattice beam is formed by mutually splicing a plurality of prefabricated beam body units, the beam body units are simpler to manufacture, lighter to install and easy to adjust during installation, and the construction period is greatly shortened.

(4) The prefabricated lattice beam can realize standardized management and production in the process of prefabricating in a factory, so that the prefabricated lattice beam can reach the optimal state in terms of stress and shape, and the quality of the prefabricated lattice beam is ensured.

(5) The invention carries out the comparison and selection of the hoisting points of the prefabricated lattice beam, optimizes the hoisting scheme and is beneficial to the section optimization.

Drawings

FIG. 1 is a flow chart of fabrication of an assembled prestressed anchor cable frame beam;

FIG. 2 is a schematic diagram of a cross beam shaping side mold structure; wherein (a) is a top view, (b) is a side view of the long axis direction of the shaping side die, and (c) is a side view of the short axis direction of the shaping side die;

FIG. 3 is a schematic structural view of a cross beam and a straight beam; wherein (a) is a front view of a cross beam of 5.5m by 2.9 m; (b) is a cross-sectional view taken along line 1-1 of figure (a); (c) is a cross-sectional view 2-2 of figure (a); (d) is a front view of a straight beam; (e) is a cross-sectional view taken along line 1-1 of FIG. (d);

FIG. 4 is a flow chart of positioning based on mobile signal tower point monitoring;

FIG. 5 is a point location diagram of a steel bar stress gage; wherein (a) is a cross beam, and (b) is a straight beam;

FIG. 6 is a schematic view showing the arrangement of the sites of the earth pressure cell; wherein (a) is a cross beam, and (b) is a straight beam;

FIG. 7 is a schematic diagram of a steel strand tensioning process;

FIG. 8 is a schematic view of a suspension point wherein (a) is a cross beam and (b) is a cross beam;

FIG. 9 is a schematic view of a force analysis of a secondary slope;

FIG. 10 is a schematic view of a force analysis of a first grade slope;

FIG. 11 is a construction flow chart;

FIG. 12 is a front view of a guard rail;

FIG. 13 is a side view of a guard rail;

fig. 14 is a schematic view of a slope structure in a test site.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail with reference to the accompanying drawings in conjunction with the following detailed description. It should be understood that the description is intended to be exemplary only, and is not intended to limit the scope of the present invention. Moreover, in the following description, descriptions of well-known structures and techniques are omitted so as to not unnecessarily obscure the concepts of the present invention.

Novel assembled anchor rope frame construction compares with traditional cast-in-place formula anchor rope frame construction as a slope disaster prevention and cure new technology, and the construction mechanization degree is high, and is of high quality, and the appearance is pleasing to the eye, can reduce slope construction period by a wide margin, reduces construction period geological disaster risk, promotes slope disaster prevention and cure technical merit. The novel assembly type anchor cable frame structure has remarkable advantages for emergency disposal of sudden slope disasters, is a technical scheme for preventing sudden geological disasters affecting traffic on time in advance, and is also an emergency plan for propelling project construction in full order.

Manufacturing method of prestressed anchor cable frame beam

Referring to fig. 1, the manufacturing method of the prestressed anchor cable frame beam comprises the following steps:

1. determining the size parameters of a prefabricated part unit of the prestressed anchor cable frame beam;

according to the size of a slope to be reinforced, the laying range of a prestressed anchor cable frame beam is determined, a prefabricated part unit is determined, the prefabricated part unit is composed of 5.5m × 2.9m cross beams and 2.7m straight beams, and the number of the cross beams and the number of the straight beams are determined. The structure of the cross beam and the straight beam is shown in figure 3.

2. Manufacturing a sizing side mold with matched size according to the size parameters of the cross beam and the straight beam, and building a bottom mold; in order to guarantee the construction period and the appearance effect of the prefabricated frame beam, a mode of combining the brick bottom die with the shaping side die is adopted, the side die can be detached when the strength of the concrete of the component reaches 2.5MP, and the utilization rate of the template is improved. The cross beam and the straight beam are manufactured by similar methods.

2.1 prefabricated yard construction

And selecting a prefabricated part field according to the position of the side slope and the land use condition. The field area is provided with 6 functional areas such as a raw material storage area, a steel bar processing area, a semi-finished product storage area, a component maintenance area, a component storage area and a factory road, and is provided with a guard gate room.

The prefabricated part field is used for carrying out labor force, material and equipment configuration;

2.2 Forming side forms

According to the design drawing of the precast beam, a qualified manufacturer is entrusted with shaping production, the construction drawing of a building and a structure is consulted in detail, the drawing is deeply designed, the overall stability of a template frame body is considered in comparison with the actual condition of an engineering during template design, the template is subjected to anti-corrosion and anti-rust treatment and a load test before leaving a factory, the manufacturer is required to pre-assemble the template so as to check the design and the processing quality, the successful installation at one time during construction of a construction site is ensured, and two schemes of a steel template and an aluminum template are adopted. The mechanism after the splicing of the shaping side die is shown in figure 2.

2.3 bottom die construction

The bottom die of the prefabricated part is built by adopting 240 × 120 × 115mm red bricks, and firstly, the measurement and the line laying positioning are carried out → the foundation leveling → the brick body building → the brick die mortar plastering are carried out.

3. Preparing a steel bar framework according to the unit size of the prefabricated part and installing the steel bar framework to the bottom die;

3.1 fabrication of reinforcing bars

The processing process flow of the reinforcing steel bar is as shown in figure 4:

(1) raw material entering field

When entering the field, the steel bar must have the certification of qualified quality, the surface of the steel bar or each bundle (disk) of steel bar should have a mark, and the surface of the steel bar must not have cracks, scars, creases and corrosion. After passing the inspection, the steel bars are respectively stacked in the raw material storage area of the steel bar processing field according to the specification, the use position and the number, and a sign signboard is set according to the requirement.

(2) Steel bar blanking

The blanking size of the steel bar is strictly blanked and cut according to the drawing size, so that the geometric size and the stress condition of the steel bar component are ensured to meet the design requirements.

When the reinforcing steel bar is blanked: drawing a cutting line of the steel bar on the steel bar by chalk according to the size of the steel bar on a drawing, and cutting the steel bar by a cutting machine. The blanking of the same specification and variety of reinforcing steel bars is reasonably arranged, so that the factory specification and the length of the reinforcing steel bars can be fully utilized. The blanking length of the reinforcing steel bars of all parts is fully calculated, the productivity of the bent parts of the reinforcing steel bars is considered, and the processing error of the reinforcing steel bars is reduced. The waste of the steel bars is reduced as much as possible according to the standard requirements and the length of the joint.

Secondly, short-length and long-length materials are forbidden to be used, accumulated errors are avoided, the position of the sizing plate is adjusted before operation, 1-2 pieces of the sizing plate are cut off, and mass production can be carried out after the size is checked. After the steel bar is cut, if the split, the shrinkage head and the seriously deformed elbow are found, the part is cut off, and the deviation of the cutting length of the steel bar meets the design regulation. And (5) blanking the reinforcing steel bars which do not meet the design requirements again.

Finally, the steel bars after blanking are orderly stacked according to specification, model and use positions, and the steel bars used firstly are arranged outside as much as possible during stacking, so that time is saved, and working efficiency is improved.

(3) Processing of reinforcing bars

Before the steel bar is processed, the surface of the steel bar is checked again to remove oil stains, paint stains and cement paste on the surface of the steel bar, and the steel bar is knocked by a hammer to peel off the steel bar, such as floating skin, old rust and the like. The steel bars should be straight without local bending. When the reinforcing steel bar needs to be straightened, the surface of the straightened reinforcing steel bar should not have scars weakening the section of the reinforcing steel bar. The bending of the steel bars and the connection of the steel bars meet the requirements of drawings and specifications.

(4) Inspection of finished products

And (4) checking and accepting the welded joints, the sizes and other indexes of the processed steel bars according to design requirements, and stacking the steel bars qualified in the acceptance inspection in a finished product qualified area in a classified manner.

3.2 Rebar and sensor mounting

(1) Installation of reinforcing bars

The steel bars are bound by 20-22 # iron wires in a staggered manner point by point in a splayed manner, and the binding wires cannot extend into the concrete protective layer; in order to ensure the thickness of the reinforcing steel bar protective layer, C40 concrete cushion blocks with the same label are arranged between the reinforcing steel bars and the template and are arranged in a quincunx shape, each square meter is not less than 4, reinforcing steel bar joints are required to be arranged in a scattered way, and the area of the same cross section is not more than 25 percent of the total cross section area of the reinforcing steel bars.

(2) Sensor mounting

Mounting of stress meter for steel strand

The steel strand stress meter is welded on a main reinforcement of the steel reinforcement framework, the steel strand stress meter is sleeved outside a high-strength PVC pipe with the diameter of 80mm, and the two ends of the PVC pipe are plugged by a polyurethane foaming agent to prevent concrete from wrapping the stress meter.

Installation of steel bar stressometer

The steel bar stressometer is fixed on the main reinforcement of the precast beam by a butt-welding method according to the position of a design drawing, the protection of a lead is noticed in the welding process, and meanwhile, the physical cooling of the sensor is carried out by a wet towel, so that the sensor is prevented from being damaged due to overhigh temperature. The location of the rebar stresses is shown in fig. 5.

Mounting concrete surface stress meter

After the precast beam concrete is poured, the concrete surface stress meter is installed on the surface of the frame beam according to the position of a design drawing when the strength reaches 30MP, holes are drilled by an electric drill, and the concrete surface stress meter is fixed by a phi 8mm expansion screw, as shown in figure 5.

Mounting of soil pressure cell

The distribution rule of the soil pressure of the test basement soil of the soil pressure box is shown in figure 6, the measuring range is 0.5MPa, the soil pressure box is buried under a longitudinal beam and a cross beam of a frame beam, a round pit with the depth of 2cm slightly larger than that of the soil pressure box is firstly dug at the position where the soil pressure box needs to be buried, fine sand is used for filling and leveling, and then the soil pressure box is fixed in place. The working surface of the pressure box in place is flush with the base surface, and the back surface of the pressure box is protruded so as to be integrated with concrete pouring of a structural object, and the pressure direction is kept consistent with the axial direction of the pressure box, so that errors caused by unbalance loading are avoided.

4. Mounting the shaping side die to the bottom die, and pouring concrete in layers; after the preset strength is reached, the shaping side die is dismantled; curing the concrete;

4.1 concrete pouring

The concrete is marked with C40 according to the design drawing requirements, is intensively mixed in a mixing station, is transported to the site by a concrete transport vehicle, and is poured in a mold entering mode of a chute.

The concrete is poured and tamped layer by layer, the vibrator is vertically inserted into the concrete, the vibrating rod is inserted into the concrete quickly and slowly, the vibrating time of each vibrating point is 20-30 seconds, the time is not too long, so that the vibrating rod is prevented from vibrating and sand-casting, and the vibrating rod is inserted into the lower layer for 5-10cm, so that the upper layer concrete and the lower layer concrete are connected into a whole. The moving distance is not more than 1.5 times of the effective vibration radius, each part is vibrated until no bubble emerges, and the vibrating rod is slowly lifted out while vibrating; avoid the vibrating spear to collide template, reinforcing bar and other built-in fitting.

The vibrating rod cannot be used for enabling the concrete to flow or convey the concrete for a long distance in the formwork, so that the concrete is caused to be separated. For each vibration part, the vibration must be carried out until the concrete is compacted at that part. The dense mark is that the concrete stops sinking and no bubbles appear, and the surface is flat and is full of slurry. But must not be over vibrated to cause the concrete surface to sand.

And fourth, the concrete tamping receiving surface is not disturbed before final setting after calendaring. The concrete pouring should be performed continuously, for example, when the concrete pouring must be interrupted for this reason, the interruption time should not be longer than the initial setting time of the concrete in the front layer.

And fifthly, the test pieces with the same conditions are manufactured according to the specifications and subjected to strength inspection, so that the traceability is realized.

4.2 curing of concrete

(1) The concrete curing adopts the mode of spraying curing agent and curing plastic film, and the curing time is not less than 14 days.

(2) After the concrete is initially set, a curing agent is sprayed (the dosage of the curing agent is 10 square meters per kg), and after the curing agent is sprayed, plastic cloth is covered on the outer surface of the concrete to prevent moisture from evaporating after two hours, and the plastic cloth needs to be tightly and firmly covered to prevent the curing effect from being influenced by wind.

5. Tensioning according to a set prestress value;

5.1 preparation before prestressing

(1) The surface quality of the beam concrete is checked, slight defects allow repair treatment (such as defects, pitted surfaces and bubbles at non-prestressed parts) after prestress application, and the operation of the procedure cannot be carried out when the defects are serious.

(2) And (5) checking whether the strength and the age of the beam concrete meet the design requirements.

(3) The jack and the oil pressure gauge have no abnormal phenomenon in the correction period.

(4) The anchor device which is matched and qualified through inspection is used, and dirt cannot be stained.

(5) And (4) checking whether the used prestressed steel strand is accurate or not, and preventing the exposed part from being damaged or twisted.

(6) And removing impurities on the anchor backing plate at the tensioning end of the beam body so as to ensure the close contact between the anchor and the anchor backing plate.

(7) Installing a working anchor on steel strands at two ends (the steel strands cannot be twisted in a staggered way), sleeving the clamping pieces on the steel strands in sequence, slightly driving the clamping pieces into anchor holes by using a steel pipe with the diameter of 20mm (all the clamping pieces are required to be basically neat and consistent), and installing a limiting plate. The steel strand bundle is inserted into the jack, the center of the anchor is aligned with the center of the pore channel, the position of the jack is adjusted to enable the jack, the pore channel and the anchor to be positioned on the same axis (three are concentric), and after the jack is in contact and close contact with the limiting plate and the anchor, the tool anchor and the tool clamping piece are installed at the top end of the jack.

5.2 prestressed tension

The tension of the steel bundle adopts tension force and elongation value double control. And controlling the corresponding tension of the jack under the stress according to the actually measured anchor. According to a design drawing, firstly, stretching to 10% of the designed stretching force, and recording the elongation value; then tensioning to 20%, and recording the elongation value; and finally, tensioning to the design stress, keeping for 5min, and recording the elongation value. The tensioning procedure of the post-tensioning low-relaxation prestressed steel strand is shown in figure 7.

When the tension reaches the design tonnage, the difference between the sum of the actual measured extension amounts at the two ends and the design extension amount is not more than +/-6 percent, if the difference exceeds the range, the reason is found out and if necessary, the reason is connected with the design department.

6. Sealing anchors of the prefabricated part units;

(1) the steel strand cutting is carried out before grouting, a grinding wheel cutting machine is needed for cutting the strand, electric arc burning cutting is strictly forbidden for any prestressed steel bar, and the distance between the cutting position of the steel strand and the outer end of the anchor is not less than 30 mm.

(2) Before sealing, the anchor recess is chiseled, the chiseling is fully and uniformly, the chiseling area is not less than 90%, the depth is not less than 5mm, and the surface has no mortar. After scabbling, the anchor recess must be cleaned up, and before sealing and pouring concrete, it is cleaned up by water.

(3) The anchor sealing concrete is compacted by tamping, has no honeycomb pitted surface, is timely plastered and calendered, and the platform of the concrete surface and the beam end surface after anchor sealing is not more than 2 mm. And (4) carrying out moisture preservation and heat preservation maintenance on the anchor sealing concrete, carrying out waterproof treatment after the maintenance is finished, and coating waterproof materials on the outer side of the anchor groove.

7. And hoisting the prefabricated part units on the treated slope surface, and stretching, grouting and sealing the anchor cables of the prefabricated part units to form the prestressed anchor cable frame beam.

7.1 precast Beam transfer

For convenient construction, the vehicle-mounted crane is rented, the precast beam is conveyed to a construction site, and semi-finished products and finished products are strictly protected in the transfer process.

7.2 precast beam hoist and mount

7.2.1 hoisting point selection because the gravity load and the pre-stressed load of the longitudinal beam can generate a large negative bending moment when the two points of the cross beam are hoisted, the two points of the longitudinal beam are hoisted through stress calculation, as shown in fig. 8.

7.2.2 initial Anchor force selection

(ii) initial anchoring force of second grade slope (1: 1)

The slope condition is shown in fig. 9, the slope body is a medium-stroke slate layer, and the friction coefficient is 0.35 (considering the complex reduction of the contact surface condition); the slope ratio is 1:1, the anchoring angle is 25 degrees; the beam body is a 5.5x2.9m cross beam with the self weight of 5 tons. The friction coefficient is selected from table 1.

TABLE 1 coefficient of friction

According to fig. 9, the calculation is carried out according to the stress balance of the beam body:

G·sin45°+P₂＝N

G·cos45°＝P₁+μN

the relationship between G and P can be obtained by combining the two formulas as follows:

when the slope surface is smooth, the friction force mu is considered to be 0.35, and the finishing result is that:

P＝0.687G＝0.687x5t＝3.435t

if the anchoring load is 40t, the initial anchoring force should not be lower than 3.435/40-0.086 times the anchoring force.

When the slope surface is not flat, namely the friction force mu is not considered to be 0, finishing the steps as follows:

P＝2.07G＝2.07x5t＝10.35t

if the anchoring load is 40t, the initial anchoring force should not be lower than 0.26 times the anchoring force, which is 10.35/40.

In summary, the minimum value of the anchoring force is 0.26 times the anchoring force, and considering a safety factor of 1.2, an initial anchoring value of 0.35 times the anchoring force is recommended.

② initial anchoring force of first grade slope (1: 0.75)

The slope situation is shown in fig. 10. The slope body is a medium-stroke fluidized bed rock layer, and the friction coefficient is 0.35 (considering the complex reduction of the contact surface condition); the slope ratio is 1:0.75, the anchoring angle is 25 degrees; the beam body is a 4.9x2.9m cross beam with a self weight of 4.5 tons, as shown in Table 1.

Calculating according to the stress balance of the beam body:

G·sin37°+P₂＝N

G·cos37°＝P₁+μN

μ(0.602G+Pcos12°)+Psin12°＝0.799G

thirdly, when the slope surface is smooth, the friction force mu is considered to be 0.35, and the slope surface is finished to obtain:

P＝1.07G＝1.07x5t＝5.35t

if the anchoring load is 40t, the initial anchoring force should not be lower than 0.134 times the anchoring force, which is 5.35/40.

When the slope is not flat, namely the friction force mu is not considered to be 0, finishing to obtain:

P＝3.84G＝3.84x5t＝19.2t

if the anchoring load is 40t, the initial anchoring force should not be lower than 0.48 times the anchoring force, which is 19.2/40.

In summary, the minimum value of the anchoring force is 0.48 times the anchoring force, and considering 1.2 safety factors, the initial anchoring value is recommended to be 0.6 times the anchoring force.

7.3 prefabricated part backing construction

(1) Construction process flow

Back lining plugging → grouting material mixing → grouting material curing

(2) Backing block

And (3) plugging gaps between the precast beam and the slope surface by adopting mortar, arranging exhaust holes (also used as observation holes) at a vertical distance of 1m, and maintaining for at least 7 days.

(3) Mixing of grouting material

The grouting material comprises the following components in percentage by weight: cement, water glass: the slurry was stirred with a hand mixer at 12:20:3:0.7 as the swelling agent.

② the weighing of each component of the raw material should be accurate +/-1% (even mass meter).

Thirdly, before stirring, cleaning the equipment, wherein the cleaned equipment does not contain residues or accumulated water.

The operation sequence of slurry stirring is as follows: firstly, 80-90% of the actual mixing water is added into a mixing tank, the hand-held mixer is started, the expanding agent is uniformly added while mixing, and then all cement is uniformly added. Adding all the powder materials, and stirring for 2 min; then adding the rest 10-20% of the mixing water, and continuing stirring for 2 min.

Fifthly, after the mixture is stirred evenly, the on-site machine output fluidity test is carried out, the range of the machine output fluidity is 18s +/-4 s, and the mixture can be used after the fluidity meets the standard.

(4) Grouting

The prefabricated beam back lining adopts gravity type grouting, in order to ensure grouting compactness, grouting is carried out through the tensioning anchor backing plate grouting holes and the top of the prefabricated member respectively, the periphery of the prefabricated beam is closely observed in the grouting process, grouting is stopped in time when grouting leakage occurs, and plugging is carried out.

Second, construction process

1. Preparation for construction

1.1 manufacturing the prestressed anchor cable frame beams with required quantity according to the manufacturing method of the assembled prestressed anchor cable frame beams.

1.2 set up construction scaffold and operation platform

(1) Slope protection construction operation platform adopts fastener formula full steel pipe scaffold, and the steel pipe is 48 x 3, Q235 steel. The distance between the transverse vertical rods is 1.1 m, the distance between the vertical rods on two sides of the sash beam is 0.8m, the distance between the longitudinal vertical rods is 1.5m, the step pitch is 1.5m, the bottom of each vertical rod is provided with a 50mm thick lumber skid, and the length of each vertical rod is not less than 3 spans; one cross brace is arranged every 12 m, the overlapping length of the cross braces is not less than 1m, and the cross braces are connected by three fasteners; a vertical and horizontal floor sweeping rod is arranged at the position which is not more than 200mm away from the ground. In connection with fig. 12-13.

(2) The platform is faced frontier defense scaffold and is set up: the adjacent side guard bar is made of phi 48 steel pipes. The guardrail height is not less than 1.2m, pole setting interval 2m, the horizontal pole twice, first liftoff be not more than 200mm jointly, do simultaneously and sweep the ground pole, the red alternate paint of rail longitudinal bar brush, length 400mm, the guardrail lower limb is 200mm high fender sole, keeps off the red alternate paint of foot board brush, interval 100 mm. The guardrail is provided with an inclined strut every 4 meters.

2. Measuring and setting out anchor holes, processing the anchor holes, cleaning the anchor holes, and inserting anchor cables into the anchor holes;

the anchor cable construction is from top to bottom, the drilling machine is organized immediately after the excavation working face comes out for drilling, the sash beam is constructed from bottom to top, and if the soil body is stable by itself and can not meet the normal construction requirements, the sash beam is constructed by subsection and separate platforms. In the construction process, the anchor cable and anchor rod drilling construction has certain destructive influence on soil, the soil structure can be disturbed, the soil is loosened, and necessary temporary support measures are prepared in excavation if the soil collapses.

2.1 Anchor eye measurement payoff

According to the requirements of a design elevation, the distance between the anchor cables is 3m multiplied by 3m, the distance between the first row of anchor cables and the slope top is 2m, and the distance between the bottom row of anchor cables and the slope bottom is 2 m; in the construction range of the anchor cable, the start and stop points are provided with fixing piles by using instruments, the middle points are encrypted according to conditions, and the anchor cable is guaranteed not to be damaged in the construction stage. Other hole sites are measured by taking the fixing piles as standard steel rulers, the whole section is uniformly lofted, and the error of the hole sites is not more than +/-50 mm. And (4) embedding a semi-permanent mark at the determined hole site, and setting out while strictly forbidding construction.

2.2 drilling apparatus

And (4) selecting a drilling tool, namely selecting drilling equipment according to the category of the anchoring stratum, the hole diameter of the anchor rod, the depth of the anchor rod, the construction site condition and the like. Drilling a hole in the rock stratum by using a drilling machine; and adopting a pipe-following drilling technology in the stratum which is easy to collapse holes and drill sticking and burying due to broken rock stratum or soft water saturation and the like.

2.3 drill in place

A platform is built by adopting a scaffold rod with the diameter of 48mm in a range where the drilling machine can not be directly operated, the platform is fixed with a slope surface by using an anchor rod, and the drilling machine is lifted to the platform by using a tripod. Drilling construction of an anchor rod hole, building a scaffold meeting corresponding bearing capacity and stability conditions, accurately installing a fixed drilling machine according to slope measuring and placing hole positions, strictly and seriously adjusting machine positions, ensuring that the vertical and horizontal errors of the drilled anchor rod hole in position do not exceed +/-50 mm, the elevation errors do not exceed +/-100 mm, the inclination angle and the direction of a drilled hole meet the design requirements, the allowable error position of the inclination angle is +/-1.0 degrees, and the allowable error of the azimuth is +/-2.0 degrees. The intersection angle of the anchor rod and the anchor cable with the horizontal plane is 25 degrees. The installation of the drilling machine requires to be horizontal and stable, and the drilling machine needs to be checked at any time in the drilling process.

2.4 drilling mode

The drilling requires dry drilling, and water drilling is forbidden, so that the engineering geological condition of the slope rock body is not deteriorated during anchor rod construction, and the bonding property of the hole wall is ensured. The drilling speed is strictly controlled according to the performance of the drilling machine and the anchoring stratum, and the drilling hole is prevented from being twisted and reduced, so that the anchoring difficulty or other accidents are avoided.

2.5 drilling process

During the drilling process, the field construction records are made on the stratum change, the drilling state (drilling pressure and drilling speed) and some special conditions of each hole. If the drilling is not performed well, the drilling is stopped immediately, the wall-fixing grouting treatment is performed in time (the grouting pressure is 0.1-0.2 MPa), and after the cement mortar is initially set, the hole is swept again for drilling.

2.6 pore diameter and pore depth

The hole diameter and the hole depth of the drilled hole are required to be not less than the design values, the deviation of the hole opening is less than or equal to +/-50 mm, and the allowable deviation of the hole depth is +200 mm. To ensure the diameter of the anchor rod hole, the diameter of the drill bit used in practice is required to be not smaller than the designed hole diameter. In order to ensure the depth of the anchor rod hole, the actual drilling depth is required to be more than 0.2m larger than the designed depth.

2.7 Anchor eye cleaning

After the drilling reaches the designed depth, the drilling can not be stopped immediately, the stable drilling is required for 1-2 minutes, and the hole bottom is prevented from being sharp and extinguishing and the designed hole diameter can not be reached. The wall of the drilled hole is not required to be provided with sediment and water body viscosity, the drilled hole is required to be cleaned, and after the drilling is finished, high-pressure air (wind pressure of 0.2-0.4 MPa) is used for completely removing rock powder and water bodies in the drilled hole out of the drilled hole, so that the bonding strength of cement mortar and rock-soil bodies on the wall of the drilled hole is prevented from being reduced. Except for the relatively hard and complete rock anchoring, high-pressure water washing is not required. If pressure-bearing water flows out of the anchor hole, anchor bars and grouting can be arranged below the anchor hole after the water pressure and the water quantity are reduced, and drain holes are arranged at proper positions around the anchor hole for treatment if necessary. If the design requires to treat the accumulated water in the anchor hole, the method of grouting, plugging, secondary drilling and the like is generally adopted for treatment.

2.8 Anchor eye inspection

After the anchor rod hole is drilled, the next procedure can be carried out after the anchor rod hole is qualified through field supervision and inspection. The hole diameter and the hole depth are generally inspected under the condition that the designed hole diameter, the drill bit and the standard drill rod are used for inspecting the hole under the site supervision and other stations, the drill bit is required to be smoothly pushed in the hole inspection process, impact or shaking is not generated, the inspection length of the drilling tool meets the designed hole depth of the anchor rod, the drill withdrawal requirement is smooth, and the high-pressure air is used for blowing and inspecting the hole without obvious splashing dust and slag and water body phenomena. Meanwhile, the hole position, the inclination angle and the direction of the anchor hole are required to be rechecked, and after all anchor hole construction items are qualified, the anchor hole drilling inspection is qualified.

2.9 Anchor rod body, anchor cable body manufacturing and installation

(1) Anchor cable manufacturing and installation

1) Material

The steel strand adopts phi S15.24(S is the specified steel strand use model) high-strength low-relaxation steel strand, the standard strength of the steel strand is not less than 1860MPa, the unbonded steel strand is adopted, the anchorage device adopts OVM15-4 type anchorage device, the design tonnage of each hole is 400-600 kN, and the grouting pipe adopts phi 25PVC pipe.

The cement for grouting adopts P.0.4 and 2.5 grade ordinary portland cement. The water-cement ratio of the grouting cement slurry is as follows: 1:0.5.

2) Manufacturing and installation of anchor cable body

The steel strand is made of high-strength and low-relaxation steel strand of phi S15.24, a phi 25PVC grouting pipe is arranged in the steel strand, and the steel strand is arranged around the steel strand. An isolating ring is arranged at intervals of 2.0m, a positioning piece is added on the anchor cable outer sleeve so as to be centered after the anchor cable is inserted into the hole, and a guide cap is arranged at the tail end of the anchor cable.

The whole anchor cable is longer than the designed length of 1.5m so as to extend out of the anchor for tensioning and facilitating the construction of the waist rail.

3) Lower anchor cable

Adopts a mode of manually lowering an anchor body. And inserting the manufactured anchor rod into the hole opening, centering the anchor rod and keeping the distance from the bottom of the hole by 0.5 cm. When the anchor cable is fed down, the anchor cable body is guided by the sleeve, operators coordinate and push the anchor cable body into the anchor hole uniformly with force, and the anchor cable body is ensured to be straight and not to be twisted in the hole. The anchor cable is inserted into the anchor hole, the anchor cable is placed in the middle at a distance of 0.5m from the bottom of the hole, the length of the steel strand is reserved outside the anchor hole by 1.5m, a carrying fulcrum is not more than 2m when the anchor cable is placed, and the turning radius is preferably not less than 10m, so that the anchor cable is not distorted and deformed in the carrying process. And (5) after the anchor cable is fed, pulling out the sleeve by using a tube drawing machine. When an anchor cable is put down, the head of the grouting pipe is tied by a No. 14 iron wire to leave a hook, the grouting pipe is hooked, the grouting pipe is put into the hole bottom along with the grouting pipe, the grouting pipe is lightly taken after grouting is finished, the iron wire is straightened and separated from the anchor cable, the grouting pipe can be taken out, and the grouting pipe is preset in the middle of the anchor body by the anchor cable and is put into the hole bottom along with the anchor cable.

3. Anchoring grouting

The grouting of the anchor hole adopts cement mortar, and the ratio of the mortar to the sand is 1:1, the water-cement ratio is 0.45-0.5, the grouting pressure of the anchor rod is not less than 0.4MPa, and the grouting pressure of the anchor cable is not less than 0.5 MPa. The grouting body is required to be full and compact, and the strength of the grouting body is required to be more than or equal to 35 Mpa. The slurry should be stirred uniformly and sieved, and the grouting pipeline should be kept smooth frequently. For rock masses with short stabilization times, resin or early strength cement mortar can be used for bonding. If necessary, an appropriate amount of an expanding agent may be added to the slurry, as required. And (3) preparing a mortar strength confirmation test block on site during mortar mixing, and after the curing period is over, submitting the pressure resistance to supervision and engineering for approval.

And (3) conveying the slurry to the bottom of the hole by using a slurry pump, returning the slurry to the orifice from the bottom of the hole, stopping grouting when the concentration and the color of the slurry overflowing from the orifice are consistent with those of the poured slurry, or determining the grouting amount according to the inscription in the slurry mixing basin, and sealing and pouring by using a stopper during grouting. The anchor cable fills the anchoring section and the free section at the same time, and mortar is filled between the sleeve and the hole wall. The anchor rod is filled with the anchoring section through the first grouting, and is filled from the anchor head reserved hole after the anchor rod is tensioned and locked for the second time. And the anchor rod is circularly grouted for multiple times until the anchor rod is full.

4. After the cement mortar in the anchor hole reaches more than 80%, tensioning the anchor cable, and fixing the anchor cable on an anchorage device after tensioning;

tensioning the prestressed anchor cable after the strength of cement mortar in the hole reaches more than 80%, wherein the prestressed anchor cable is tensioned, the initial anchoring value of tensioning the second-grade slope anchor cable is 0.26-0.35 times of anchoring force, and the initial anchoring value of tensioning the first-grade slope anchor cable is 0.48-0.6 times of anchoring force; the applied prestress value is 1.1 times of the design value, and the elongation of the steel strand is recorded in each stage in the tensioning process; and performing additional tensioning on the 7 th day after tensioning; and during tensioning, if the difference between the actual elongation value and the theoretical value is more than +/-6%, suspending the tensioning and finding out the reason. .

After the anchor cable is subjected to overstretching, the anchor cable is locked on the anchorage device, the locking process is emphasized, and the inward shrinkage of the clamping piece is reduced to prevent the loss of the prestress. And cutting off the excess length of the steel strand after locking, and cutting off the steel strand by using a grinding wheel cutting machine. When the prestress attenuation after locking is expected to be overlarge, a certain length of steel strand needs to be reserved for retension.

Quality control

Firstly, hole positions are determined according to design requirements before drilling, the allowable deviation of the hole positions is +/-100 mm in the horizontal direction, +/-50 mm in the vertical direction, the allowable error of the blanking length of the anchor cable is +/-50 mm, the allowable deviation of the inclination of the drill hole is 3%, and the actual drilling depth is 0.5m over the design length.

Secondly, the slurry of the prestressed anchor cable is cement paste, and a basic test is performed before the anchor cable is constructed so as to check and determine relevant design parameters.

And thirdly, the strength of the anchoring body reaches 80% of the design strength, the anchoring body can be tensioned when the strength is more than 20MPa, and the anchoring body can be tensioned and locked after general grouting is completed for seven days (when the average temperature is more than 20 ℃).

And fourthly, taking at least one group of test pieces for each 30 anchor rods of the anchoring bodies according to the number of the anchor rods, wherein each group of test pieces has 6 test pieces with the specification of 70.7 multiplied by 70.7 mm.

5. And (5) sealing the anchor by using the anchor head.

And locking after tensioning in place, mechanically cutting redundant steel strands, strictly prohibiting electric cutting and oxygen cutting, and preventing the slippage of the anchor head steel strands by more than or equal to 30 cm. And C30 concrete is adopted for sealing the anchor, and the concrete is maintained for not less than 14 days after the thickness of the sealed anchor is not less than 20 mm.

The ramp structure that can be obtained is shown in fig. 14. The straight beam is arranged between the longitudinal positions of the two cross beams, so that the dead weight of the beam body can be reduced as much as possible, and the requirement on slope surface protection can be met.

The invention has the characteristics of simplifying construction steps, shortening construction period, reducing construction risk, realizing standardized management production, ensuring product quality, being economical, practical and environment-friendly. The invention can replace the existing cast-in-place anchor rod (cable) lattice beam to carry out slope reinforcement, has outstanding advantages in slope emergency reinforcement, and is also suitable for carrying out slope rapid reinforcement construction in reconstruction and extension of highways.

In conclusion, the invention relates to a method for manufacturing and constructing an assembled prestressed anchor cable frame beam for slope reinforcement, which can improve the section performance of the beam and bear larger anchoring force, and solves the defects that the traditional cast-in-place reinforced concrete lattice beam is pulled to crack at the midspan position when the anchoring force of an anchor cable is larger, so that the steel bar of a component is easy to corrode in a rainfall frequent area and the rigidity is reduced; the mechanical property is greatly improved. The thickness of the beam body can be reduced or stressed steel bars can be reduced, and the material utilization rate is improved, so that the beam is more economical. The prestressed anchor cable frame beam is formed by mutually splicing a plurality of precast beam body units, the beam body units are simpler to manufacture, lighter to mount and easy to adjust during mounting, and the construction period is greatly shortened.

It is to be understood that the above-described embodiments of the present invention are merely illustrative of or explaining the principles of the invention and are not to be construed as limiting the invention. Therefore, any modification, equivalent replacement, improvement and the like made without departing from the spirit and scope of the present invention should be included in the protection scope of the present invention. Further, it is intended that the appended claims cover all such variations and modifications as fall within the scope and boundaries of the appended claims or the equivalents of such scope and boundaries.

Claims

1. A manufacturing method of an assembled prestressed anchor cable frame beam for slope reinforcement is characterized by comprising the following steps:

(6) respectively sealing the cross beam and the straight beam;

2. The method for manufacturing the assembled pre-stressed anchor cable frame beam for slope reinforcement according to claim 1, wherein the shaping side mold is made of steel or aluminum mold plates, and is subjected to anti-corrosion and anti-rust treatment, load test and pre-assembly before leaving factory.

3. The method for manufacturing the assembled pre-stressed anchor cable frame beam for slope reinforcement according to claim 1 or 2, wherein the bottom die is built by red bricks, firstly, measurement and setting-out positioning are carried out, then, foundation leveling is carried out, bricks are built, and then, mortar is used for plastering.

4. The fabrication method of an assembled prestressed anchor cable frame girder for slope reinforcement according to claim 1 or 2, wherein preparing a steel-reinforced skeleton according to the prefabricated unit size includes: screening the steel bars, selecting the steel bars and the steel strands meeting the requirements, blanking, welding the steel bar framework, installing the steel strands, and checking and accepting the installation quality of the steel bars and the steel strands;

5. The method for manufacturing the assembled prestressed anchor cable frame beam for slope reinforcement according to claim 4, further comprising a sensor installation, specifically comprising:

6. The method for manufacturing an assembled prestressed anchor cable frame girder for slope reinforcement as claimed in claim 1 or 2, wherein the layered casting of concrete comprises:

7. The method for manufacturing the fabricated prestressed anchor cable frame beam for slope reinforcement as claimed in claim 6, wherein the step of pouring concrete in layers further comprises:

8. The method for manufacturing the fabricated prestressed anchor cable frame girder for slope reinforcement as claimed in claim 1 or 2, wherein the curing of concrete includes: spraying curing agent after the concrete is initially set, wherein the using amount of the curing agent is 10 square meters per kg, covering plastic cloth on the outer surface of the concrete to prevent moisture from evaporating after the curing agent is sprayed for two hours, and the curing time is not less than 14 days; and when the strength of the concrete reaches 2.5MP, the shaping side die is disassembled.

9. The method for manufacturing the fabricated prestressed anchor cable frame girder for slope reinforcement according to claim 1 or 2, wherein the tensioning according to the set prestress value includes: firstly, stretching to 10% of a set prestress value, and recording the concrete elongation value; tensioning to 20% of the set prestress value, and recording the concrete elongation value; finally, stretching to a set prestress value, and recording the elongation value of the concrete; the difference between the sum of the elongation values of the two ends and the design value is not more than +/-6%, and if the difference exceeds the range, the reason is found out.

10. The fabrication method of an assembled pre-stressed anchor cable frame beam for slope reinforcement as claimed in claim 1 or 2, wherein the pre-fabricated unit block anchor comprises:

11. The method for manufacturing the assembled prestressed anchor cable frame beam for slope reinforcement according to claim 1 or 2, wherein the prefabricated unit is a cross-shaped two-or-one beam, and comprises a middle main body and two or four extension arms uniformly extending outwards from the main body vertically, and the length of the extension arms is set according to requirements; the section of the extension arm is rectangular; the middle main body is of a cubic structure.

12. The method for manufacturing the fabricated prestressed anchor cable frame girder for slope reinforcement as claimed in claim 1 or 2, wherein the tensioning of the anchor cables of the prefabricated units comprises:

13. The fabrication method of an assembled prestressed anchor cable frame girder for slope reinforcement as claimed in claim 1 or 2, wherein said prefabricated unit grouting comprises: grouting a gap between the prefabricated member unit and the slope surface for plugging, arranging exhaust holes at a vertical distance of 1m, and maintaining for at least 7 days; the grouting material comprises the following components in percentage by weight: cement, water glass: firstly, adding 80-90% of water in a stirring barrel, starting a handheld stirrer, uniformly adding the expanding agent while stirring, then uniformly adding all cement, adding all powder and then stirring for 2 min; then adding the rest water, and continuously stirring for 2 min; after the mixture is uniformly stirred, a machine-out fluidity test is carried out on site, and the machine-out fluidity range meets 18s +/-4 s.

14. A construction method for slope reinforcement is characterized by comprising the following steps:

(1) manufacturing cross beams and linear beams in required quantity by adopting the manufacturing method of the assembled prestressed anchor cable frame beam for slope reinforcement of any one of claims 1 to 13; a linear beam is arranged between the two longitudinal cross beams;

(3) grouting anchor holes of the cross beam and the straight beam;

(5) and (5) sealing the anchor by using the anchor head.

15. The method of slope reinforcement construction of claim 14, wherein the anchor eye measurement setting-out comprises: the distance between the anchor cables is 3m multiplied by 3m, the distance between the first row of anchor cables and the slope top is 2m, and the distance between the bottom row of anchor cables and the slope bottom is 2 m; the hole site error is not more than +/-50 mm.

16. The slope reinforcement construction method according to claim 14 or 15, wherein drilling is performed in rock strata by using a drilling machine during anchor hole machining, and drilling is performed in strata which are easy to collapse and drill and bury by using a pipe following drilling; in the range that the drilling machine can not be directly operated, a scaffold rod with the diameter of 48mm is adopted to erect a platform, the platform is fixed with a slope surface by an anchor rod, and the drilling machine is lifted to the platform by a three-foot bracket; the vertical and horizontal errors of the drill holes are not more than +/-50 mm, the elevation errors are not more than +/-100 mm, the inclination angle allowable error of the drill holes is +/-1.0 degree, and the azimuth allowable error is +/-2.0 degrees; the intersection angle of the anchor rod, the anchor cable and the horizontal plane is 25 degrees; the hole diameter and the hole depth of the drill hole are not less than the design values, the deviation of the hole opening is less than or equal to +/-50 mm, and the allowable deviation of the hole depth is +200 mm.

17. The method of claim 14 or 15, wherein the anchor cable is phi^S15.24 steel strand wire, with middle partArranging a phi 25PVC grouting pipe, and arranging steel strands around the grouting pipe; arranging an isolating ring at intervals of 2.0m, arranging a positioning sheet on the anchor cable outer sleeve to be centered after the anchor cable is inserted into the hole, and arranging a guide cap at the tail end; each anchor cable is 1.5m longer than the designed length so as to extend out of the anchorage device for tensioning;

18. The construction method for reinforcing the side slope according to claim 17, wherein the grouting of the anchor hole adopts cement mortar, and the ratio of the mortar to the sand is 1:1, the water-cement ratio is 0.45-0.5, the grouting pressure of the anchor cable is not less than 0.5MPa, and the strength of the grouting body meets the requirement that the strength of the anchor cable is not less than 35 MPa.

19. The slope reinforcement construction method according to claim 17, wherein tensioning the anchor cable comprises: after the cement mortar in the anchor hole reaches more than 80%, tensioning the prestressed anchor cable, wherein the initial anchoring value of tensioning the second-level slope anchor cable is 0.26-0.35 times of anchoring force, and the initial anchoring value of tensioning the first-level slope anchor cable is 0.48-0.6 times of anchoring force; the applied prestress value is 1.1 times of the design value, and the elongation of the steel strand is recorded in each stage in the tensioning process; and performing additional tensioning on the 7 th day after tensioning; and during tensioning, if the difference between the actual elongation value and the theoretical value is more than +/-6%, suspending the tensioning and finding out the reason.