系统优化Vista服务优化、系统优化攻略（Vista service optimization and system optimization）

Vista服务优化、系统优化攻略Vista service optimization andsystem optimization

Construction technology of anchor retaining wall and itsapplication in highway slope protection

Huang gang1

(China Water Conservancy and hydropower seventh EngineeringBureau Co. , Ltd. five branch, Sichuan, Pengshan 620860)Abstract: as a light retaining structure, anchor retainingwallhas been widely used in highway cutting slope protection inrecent years because of its advanced technology, reasonableeconomy and safe and reliable advantages.

This paper starts from the qiwan road anchor retaining wallslope protection system, this paper introduces theconstruction technology of anchor rod retaining wall, can beused for similar engineering construction engineering andtechnical personnel reference.

Key words: anchor; retaining wall; construction; highway slopeprotection

1 Introduction

Anchor retaining wall is a kind of retaining structure formedby bolt technique. Bolt is a new type of tension member, oneend of which is connected with engineering structures, theother end of the drill hole, insert bolt, grouting and

maintenance process in the stability of the anchorage formation,to inherit the earth pressure exerted on the structure of thethrust, thus the use of anchor bolt and formation to maintainstructure the stable. As a light retaining structure, anchorretaining wall to replace the heavy masonry gravity retainingwall, can save a lot of masonry materials, has been widely usedin highway, railway, coal and water retaining engineering, andhas received very good effect.

2 Overview

There are different forms of anchor retaining wall due to thedifferences of anchorage stratum, construction method, stressstate and structure form. According to the structure of the wall,it can be divided into column, plate, anchor, retaining walland plank type anchor rod retaining wall. Column plate anchorretaining wall is composed of retaining plate, ribs and anchorribs is bearing retaining plate, bolt is a support rib column,the wall of the lateral earth pressure acting on the retainingplate, and the retaining plate to the ribs, the ribs to thecolumn bolt. Balance by anchoring force between bolt andsurrounding strata that anchor pullout force, in order tomaintain the wall and wall rock stability; wall anchoredretaining wall is composed of a wall panel (wall panel) and ananchor rod, the wall panel directly with bolt connection, andbolt to support earth pressure through the wall panel pass tothe anchor rod, the latter relies on the anchoring force betweenthe bolt and the surrounding strata (i. e. pullout resistance)of earth pressure, in order to maintain the balance andstability of retaining wall.

The qiwan Expressway from Chongqing to Wansheng Tourist BusLine. The author built the qiwan road contract A 'Bayinterchange C ramp section of strata in the mud shale, angleof 20 degrees to 25 degrees, with purple red mud with diameterof 1 ~3cm, 5 ~ 10cm locally with thick black calcareous shale,clay particles in the main. Semi solid state, the nature ofcement, disintegration, easy weathering in the natural state,low shear strength. The roadbed design for 1 :0. 5 slope, brokendown, taking into account the generated after excavationunloading cracks and blasting influence on slope stability,sliding and produce bedding caused by dumping to prevent thecollapse of the slope, the cutting section of the column plateretaining bolt for door.

Construction of 3 anchor retaining wall

In this paper the qiwan road retaining bolt as an example,introduces the anchor retaining wall in highway slopeprotection construction technology and experience.

3. 1 project overview

The qiwan road ramp C right side slope retaining bolt end pileNo. CK0+410 ~ CK0+520, length 110m, slope 1:0.5, the highest

20.5M, the main engineering quantity: C20 concrete 305.98m3,with 100 5027m drilling, steel fabrication and installation

61.746T. The layout is shown in Figure 1 and the node is shownin figure 2.

LINK AutoCAD.Drawing. 16 D:\\ \ \ \ \ Jiang Zhiqiang papers ofretaining bolt in highway slope protection application of

anchor retaining wall section.Dwg \ \ \a\f 0 \*\p MERGEFORMATFig. 1 cross section of anchor retaining wall (unit: mm)LINK AutoCAD.Drawing. 16 D:\\ \ \ \ \ Jiang Zhiqiang papers ofretaining bolt in highway slope protection in the applicationof \\A.Dwg \a \f 0 point and drawing the \p MERGEFORMATFigure 2 A point and drawing (unit: mm)

The bolt retaining wall is designed as a column plate anchorretaining wall, and the design scheme is as follows:

Intheproject designfor the frictiontype groutinganchorbolt.Adopting 3 Phi 20 thread steel, the bending and turning partlength is not less than 90cm; the bolt support steel is Phi 8steel bars; the anchor bar steel bar must be welded into a beam;the bolt support bracket is arranged at intervals of 1.5 to 2m.The depth of the anchor hole should be greater than the depthof anchor 50cm, the diameter of the anchor hole wall is 100mm,and M30 cement mortar is used for grouting. Structure shown infigure 3.

LINK AutoCAD.Drawing. 16 D:\\ \ \ \ \ Jiang Zhiqiang papers ofretaining bolt in highway slope protection in the applicationof bolt structure diagram of.Dwg \a \ \ Andrew \f 0 \p theMERGEFORMAT Figure 3 bolt structure detail (unit: mm)LINK AutoCAD.Drawing. 16 D:\\ \ \ \ \ Jiang Zhiqiang papers ofretaining bolt in highway slope protection in the applicationof \\B-B.Dwg \a \f 0 \p section of the MERGEFORMAT

B-B section diagram (unit: mm)

The rib reinforced concrete column C20, dark rib, rib columnwidth 35cm, thickness 40cm, rib column set spacing of 2m (in) ,the main reinforcement is 20 steel, stirrup is 8 bar spacing20cm.

The sprayed concrete wall panel for C20 reinforced concrete,thickness 10cm; steel mesh is 8 steel, according to 20 * 20cmlayout and layout of the drain pipe. As shown in figure 4.LINK AutoCAD.Drawing. 16 D:\\ \ \ \ \ Jiang Zhiqiang papers ofretaining bolt in highway slope protection application ofreinforced.Dwg \a \f panel \ \ 0 \p \ * MERGEFORMAT Figure 4panel reinforced structure (section)

3.2 construction process

The construction flow chart of anchor retaining wall is asfollows:

3.2. 1 construction preparation

The mix ratio of material requirements

M30 cement mortar used for bolt grouting. Mix ratio is cement:Sand: water: expansion agent =1 :0.98:0. 53:0. 11. Cement:

P.O32.5# cement, sand as superfine sand, fineness modulus 0.7~ 1. 5.

The mixing ratio of anchor rib andpanel C20 shotcrete is cement:Sand: Crushed Stone: water: accelerator=1:1.36:4.0:0.41 :0.03.

P.O32.5# cement; cement: Sand: use coarse and hard durableJianyang, fineness modulus of 2.2 ~ 3; coarse aggregate:particle size less than 15mm shall not use gravel containingactive silica stone; gradation shall satisfy the requirementsin table 1 :

Table 1 grading of shotcrete aggregate

The serial number by the cumulative mass percentage (%) 0.6mmvarious screen 1.2mm 2. 5mm 5mm 10mm 15mm 117 ~ 2223 ~ 3135 ~4350 ~ 6073 ~ 82100213 ~ 3118 ~ 4126 ~ 5440 ~ 7062 ~ 90100:accelerating admixture selected in line with the qualityrequirements, performance of sprayed concrete mixed eleratingafter must meet the design requirements: the use of water;drinking water, more than 1%of the calculated weight of waterwater acidic water shouldnot be used for sewage and the pH valueof less than 4 and the amount of sulfate containing sulfate at.The erection of steel pipe frame platform, slope cleaningdebris, clear the pumice and loose rock, on the slope stabilityof local office cleaning or reinforce, grouting or jointingtreatment on large cracks, and then measuring and setting outon a rock face, determine the bolt hole position and marked withpaint.

3.2.2 bolt construction

The drilling

According to the design requirements, the anchor hole is 2 *2m square, with an aperture of 10cm. After the hole locationis determined, the drilling is performed with a XK300 hydraulicdrill. After drilling, the drill shall be stable. The guide baror vertical shaft is consistent with the angle of the drill rod(20 degrees to the horizontal) and is on the same axis. In theprocess of drilling, we should carefully operate, concentrate,and reasonably grasp the drilling parameters and drilling speed,and can not damage the rockmass structure, so as to avoid cracksin the rock layer to expand, and prevent drilling, drilling andso on. Kong Shen, aperture and inclination shall be inaccordance with drawing requirements. The hole positiondeviation is + 50mm; the deviation between the drilling axisand the design axis should be less than 3% hole depth; thedeviation of the hole depth is not more than+100mm; the spacingof the anchor holes should meet the requirements. The holeshould be cleaned after the rock dust hole, debris and otherdebris, keep dry and clean the hole hole wall roughness, andtimely use of plastic plug plug hole.

The bolt is made and placed

According to the designrequirements, 3 Phi 20 thread steel spotwelding into a bundle, in the anchor rod body every 2m anchoranchor support, the rod should be smooth, degreasing, rust,free segment with plastic cloth bandage. In place of bolt,should prevent rod twisting, bending; grouting pipe with boltinto the hole, pipe end from the hole bottom distance is 50 ~100mm, the rod into the hole inclination angle angle and keepconsistent, well after the anchor rod body is always in thedrilling center.

The grouting

With a hole as the working unit, the drilling of the anchor hole,the placement of bolts and grouting should be completedcontinuously. The construction technology of grouting willaffect the anchoring capacity of the anchor bolt. Beforegrouting, water is used to flush the hole wall and 1 :3 cementmortar is enclosed intheorifice 50cm. Slurry shouldbe stirredevenly, sieved, with the use of agitation, in the initialcoagulation before use, such as in the hardening of the liquidcan not be full of anchor solid, should be filled slurry,grouting quantity shall not be less than the amount ofcalculation, the filling coefficient is 1. 1 ~ 1. 3. Whengrouting, should always pay attention to the exhaust hole willnot be blocked, should be at the side of the grouting pipe drawnout, but should pay attention to the end of the pipe shouldalways be below the surface of the slurry, and at any time activegrouting pipe, until the slurry out of the hole when all out.After the grouting is finished, the exposed steel bars shouldbe cleaned and protected.

Construction of 3.2.3 anchor rib and shotcrete faceplateAfter the grouting of the bolt is completed, the loose pumiceand rock residue are cleaned again. Handle the smooth rocksurface, using mortar rubble masonry fill hole.

On the slope stability of local office cleaning or repairreinforcement grouting treatment on large cracks or gaps. Inthe anchor ribs accordingto the sizeof the drawing line, using

hand-held hammer chisel cleaning artificial rib columnfoundation trench should meet the design size of 35 * 40cm.According to the requirements of the drawings made of steel andreinforced concrete column binding rib panel, steel mesh andanchor jointsmust bewelded, to ensure that shotcrete mesh doesnot shake, and to be close to the design for the concrete surfaceof 10cm, in order to ensure the thickness of reinforcedprotective net.

Set the drain hole according to the requirements of the drawing.The length is 10cm, the orifice is close to the slope surfaceto prevent the concrete from blocking the drain hole when itis sprayed.

Before spraying concrete, rinse the sprayed surface with highpressure water to ensure the fresh and wet surface.

Before the concrete is sprayed, the test shall be carried outfirst, the amount of springback shall be adjusted, and theconstruction operation procedures shall be determined.Spraying concrete on rainy days is strictly prohibited.Concrete injection construction, in strict accordance with theC20 construction mix ratio of concrete production, sub -section, sub - section from bottom to top sub - injection.During the construction, first air, after the boot, and thenfeeding; feeding to the injection machine must be continuousand uniform, the normal operation of the machine, the hoppershould be kept enough storage; injection pressure machine,should meet the pressure at the nozzle is about 0. 1MPa; jet,nozzle and the spray surface should keep vertical. Keep the