CN111734451A - IV-type and V-type surrounding rock tunnel concrete lining anti-cracking construction method and structure thereof - Google Patents
IV-type and V-type surrounding rock tunnel concrete lining anti-cracking construction method and structure thereof Download PDFInfo
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- CN111734451A CN111734451A CN202010703374.5A CN202010703374A CN111734451A CN 111734451 A CN111734451 A CN 111734451A CN 202010703374 A CN202010703374 A CN 202010703374A CN 111734451 A CN111734451 A CN 111734451A
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D11/00—Lining tunnels, galleries or other underground cavities, e.g. large underground chambers; Linings therefor; Making such linings in situ, e.g. by assembling
- E21D11/04—Lining with building materials
- E21D11/10—Lining with building materials with concrete cast in situ; Shuttering also lost shutterings, e.g. made of blocks, of metal plates or other equipment adapted therefor
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D11/00—Lining tunnels, galleries or other underground cavities, e.g. large underground chambers; Linings therefor; Making such linings in situ, e.g. by assembling
- E21D11/04—Lining with building materials
- E21D11/10—Lining with building materials with concrete cast in situ; Shuttering also lost shutterings, e.g. made of blocks, of metal plates or other equipment adapted therefor
- E21D11/107—Reinforcing elements therefor; Holders for the reinforcing elements
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D11/00—Lining tunnels, galleries or other underground cavities, e.g. large underground chambers; Linings therefor; Making such linings in situ, e.g. by assembling
- E21D11/14—Lining predominantly with metal
- E21D11/15—Plate linings; Laggings, i.e. linings designed for holding back formation material or for transmitting the load to main supporting members
- E21D11/152—Laggings made of grids or nettings
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D11/00—Lining tunnels, galleries or other underground cavities, e.g. large underground chambers; Linings therefor; Making such linings in situ, e.g. by assembling
- E21D11/38—Waterproofing; Heat insulating; Soundproofing; Electric insulating
Abstract
The invention relates to the field of tunnel construction, in particular to a method and a structure for constructing concrete lining crack resistance of IV-type and V-type surrounding rocks, wherein the construction method comprises the steps of waterproof structure erection, supporting structure erection, lining structure pouring, backfill grouting, consolidation grouting and the like, the lining crack resistance structure comprises surrounding rocks and a lining for supporting the surrounding rocks, and further comprises a cut-off ditch arranged at the slope top of a face slope of a tunnel, a backfill grouting layer is arranged between the surrounding rocks and the top of the lining, a permanent supporting structure is arranged at the position of the surrounding rocks close to the circumferential direction of the lining, and a consolidation grouting layer is arranged at the circumferential position of the surrounding rocks with the depth of 1.5 m. The invention improves the structural strength of the IV-class and V-class surrounding rocks to a greater extent, and avoids the damage to the lining structure caused by more seepage water leaking to the lining structure; the reinforcing mesh arranged in the lining structure improves the structural strength of the lining structure; the intercepting drain can guide a large amount of precipitation away from the tunnel.
Description
Technical Field
The invention relates to the field of tunnel construction, in particular to a method and a structure for constructing IV-type and V-type surrounding rock tunnel concrete lining crack resistance.
Background
With the development of economic life, the demand of people for transportation is increasing day by day, and when a traffic road is built, tunnels are inevitably required to be dug. When a tunnel is excavated, a surrounding rock mass, which is changed in stress state due to the influence of excavation, may be called a surrounding rock, and lining refers to a permanent supporting structure constructed with materials such as reinforced concrete along the periphery of a tunnel body in order to prevent the surrounding rock from being deformed or collapsed.
The lining structure comprises surrounding rocks, a primary support and a secondary lining, wherein the primary support covers the surface of the surrounding rocks, the secondary lining is built in the primary support, the primary support is formed by spraying ceramsite concrete, a heat insulation layer and a water-proof and drainage heat insulation composite layer are arranged in the primary support, and the heat insulation layer is formed by molding ceramsite concrete. The technical scheme can ensure that the bearing capacity of the tunnel lining structure is not reduced in a high-ground-temperature environment, has good heat resistance or heat resistance, can effectively avoid cracking of the tunnel lining due to temperature stress, and is favorable for ensuring the durability of the tunnel lining structure.
The Chinese patent of invention with a Chinese granted publication No. CN106437748B discloses a separable maintainable tunnel lining structure, which comprises an arch wall primary supporting structure, a waterproof and drainage system and a lining structure which are arranged from outside to inside. The lining structure comprises an arch part secondary lining, a side wall frame supporting structure, a filler wall and a tunnel bottom pile plate structure. The tunnel bottom pile plate structure comprises a bottom plate paved on a substrate closed layer and anchor piles arranged along the longitudinal direction and the transverse direction of the tunnel at intervals, and the upper ends of the anchor piles are fixedly connected with the bottom plate. And the two circumferential ends of the water prevention and drainage system are led to longitudinal drainage ditches arranged at the two transverse sides of the bottom plate. Such a technical scheme can effectively avoid the groundwater sharply to increase but drainage capacity is not enough in rain flood season and causes the fracture destruction of side wall structure, increases lining cutting structure water pressure resistance and anti ability of floating, reduces the damage risk of groundwater to lining cutting structure especially tunnel floor structure in rain flood season.
In the prior art, a patent about tunnel lining also has a Chinese invention patent with application publication number CN107269295A, which discloses a PVA-ECC lining structure and a construction method, mainly used for reinforcing a cracked tunnel structure, and in addition, the invention patent with patent authorization publication number CN111156036A discloses a novel plate anchor structure, which is provided with a corrugated plate structure and can form a drainage channel similar to a water tank in a wave trough area separated from the lining structure, so that lining leakage water is drained to water ditches at two sides, a water-rich tunnel is ensured to have enough drainage capacity, and adverse effects caused by cracking of the lining structure are reduced to the maximum extent.
In the multiple prior art schemes, the strength of the lining is improved from different angles, and the cracking of the lining is avoided, however, the prior art lacks a lining designed for different tunnel surrounding rock strength grades, the surrounding rock of the tunnel can be divided into six types I, II, III, IV, V and VI according to the strength, wherein the IV type surrounding rock mainly refers to argillaceous and carbon slates, weakly weathered and strongly weathered rock masses, fault affected zones and fracture dense zones, and the surrounding rock masses mainly adopt a broken structure and a discrete body structure, and have poor quality. The class V surrounding rock mainly refers to a fault fracture zone, a completely weathered rock body and a covering layer tunnel section. Due to the characteristic that IV-class surrounding rocks and V-class surrounding rocks are relatively loose, more loose rock pore water and bedrock fracture water are generated during precipitation, and water generated in the environment can damage a lining structure to cause the lining structure to crack. Based on the characteristic that IV-class surrounding rocks and V-class surrounding rocks are easy to generate environmental water, more lining patent technologies are not suitable for the IV-class surrounding rocks and the V-class surrounding rocks.
Disclosure of Invention
Aiming at the defects in the prior art, the invention aims to provide the anti-cracking construction method for the IV-type and V-type surrounding rock tunnel concrete lining, which can enhance the strength grade of the surrounding rock, reduce the damage of precipitation to the lining structure and further improve the anti-cracking performance of the lining.
The invention also aims to provide a concrete lining anti-cracking structure for IV-type and V-type surrounding rock tunnels, which has the advantages that the strength grade of the surrounding rock is increased, precipitation is not easy to leak to the lining structure, and the lining structure has strong anti-cracking performance.
The above object of the present invention is achieved by the following technical solutions: the IV-type and V-type surrounding rock tunnel concrete lining anti-cracking construction method is characterized by comprising the following steps of:
step one, erecting a waterproof structure: arranging a catch basin at the top of the tunnel face side slope;
step two, erecting a supporting structure: erecting a permanent supporting structure at the surrounding rock of the tunnel, and erecting a temporary supporting structure in the tunnel, wherein the permanent supporting structure adopts one of anchor bolt supporting and concrete injection supporting, and the temporary supporting structure is a steel arch frame;
step three, pouring a lining structure: laying steel bars according to the sequence of the bottom plate, the side wall and the top arch, then laying a template by using a needle beam hydraulic self-propelled trolley, finally pouring according to the sequence of the bottom plate, the side wall and the top arch by using a concrete delivery pump, and removing the template after pouring and curing;
step four, backfilling and grouting: arranging a backfill grouting hole in the position of 10cm of the depth of the surrounding rock, starting backfill grouting when the lining reaches 70% strength, and continuing grouting for 5min and stopping backfill grouting when the grouting pressure reaches 0.4-0.6Mpa and the backfill grouting hole stops sucking grout;
step five, consolidation grouting: and 7 days after backfilling and grouting, arranging a consolidation grouting hole at the depth of the surrounding rock not less than 1.5m, starting consolidation grouting, and stopping grouting when the grouting pressure reaches 2.3-2.8Mpa and the consolidation grouting hole does not absorb grout any more.
Through adopting above-mentioned technical scheme, through the catch basin of seting up in tunnel face side slope department, can be with a large amount of precipitation water conservancy diversion elsewhere, avoid these precipitations to cause the destruction to the lining of tunnel. The erection of the supporting structure can provide certain support for the surrounding rock before the lining structure is not formed, the collapse and the crack of the surrounding rock are avoided, wherein the permanent support can be removed, the temporary support can be removed after the lining structure is built, the step of backfilling and grouting can fill the gaps between the lining and the surrounding rock, and the step of concreting and grouting can fill some gaps existing at the deeper position of the surrounding rock, so that the structural strength of the surrounding rock can be effectively improved by the two grouting steps, the damage of rainfall to the lining structure of the tunnel is reduced, and the impermeability of the lining structure is improved. In addition, when the pressure of backfill grouting reaches 0.4-0.6Mpa, the pressure of consolidation grouting reaches 2.3-2.8Mpa,
the present invention in a preferred example may be further configured to: the width of the intercepting ditch is 0.6-1.2m, and the depth is 0.6-1 m.
By adopting the technical scheme, the intercepting ditch is not too deep and too wide, the intercepting ditch is too deep and too wide and can cause soil erosion, but is not too narrow and too shallow, and the requirement of drainage cannot be met when the intercepting ditch faces larger rainfall.
The present invention in a preferred example may be further configured to: the circumferential angle of laying of the steel arch centering of IV type country rock department in the tunnel is 240 +/-2 degrees, the circumferential angle of laying of the steel arch centering of V type country rock department is 289 +/-2 degrees.
By adopting the technical scheme, the laying positions of the steel arch frames are different according to different rock mass structures of the IV-type surrounding rock and the V-type surrounding rock.
The present invention in a preferred example may be further configured to: the anchor bolt support comprises the following construction steps:
step one, drilling: drilling by adopting a pneumatic drilling pore-forming technology to obtain an anchor rod mounting hole, wherein the aperture phi of the anchor rod mounting hole is 42mm, the hole depth is 1.5m, the position of the anchor rod mounting hole is arranged along the cross-section circle of the tunnel, one anchor rod mounting hole is arranged at the circumferential angle position of every 10 degrees of the cross-section circle from the position of an axillary angle, the anchor rod mounting hole is not arranged at the position of a bottom plate, the deviation of the hole position is not more than 100mm, and the deviation of the hole depth is not more than 50; after the anchor rod mounting hole is formed, high-pressure air is used for cleaning the hole;
step two, anchor rod installation: cutting an anchor rod into 1.5m, removing rust, conveying anchoring mortar into an anchor rod mounting hole through a grouting pump, enabling the pipe orifice of a mortar conveying pipe inserted into the anchor rod mounting hole to be 5-10 cm away from the hole bottom, discharging the mortar conveying pipe after the anchoring mortar flows out of the orifice, and finally inserting the anchor rod;
wherein, the anchor rod material is deformed steel bar with phi 25 specification; the anchoring mortar for grouting anchor rod is prepared by mixing anchoring cement and anchoring sand, wherein the anchoring cement is ordinary Portland cement of over 32.5Mpa, and the anchoring sand is hard and clean medium-fine sand with particle size less than 2.5 mm.
Through adopting above-mentioned technical scheme, such a scheme obtains anchor bolt supporting construction, and it is effectual to strut, can increase the structural strength of IV class country rock and V class country rock effectively, reduces precipitation seepage to the structure department of building a course, helps the difficult fracture of guarantee building a course structure.
The present invention in a preferred example may be further configured to: the sprayed concrete support comprises the following construction steps:
step one, cleaning: before the spraying construction, pumice on the sprayed surface of the tunnel is removed, the sprayed surface is washed by wind and water, and the rock stratum which is easy to soften when meeting water is cleaned by compressed air;
step two, embedding a mark: burying a thickness mark at the surrounding rock so as to control and check the thickness of the sprayed layer;
step three, spraying: spraying in sections according to a section form of 10-20 m, and forming a work seam between sections;
step four, maintenance: and after the sprayed concrete is finally set for 2h, performing air-water curing by using a spraying machine, and curing by using a film when the ambient temperature is lower than 5 ℃.
By adopting the technical scheme, the sprayed concrete can be better attached to the surface of the surrounding rock by cleaning the sprayed surface, and the concrete spraying operation can be conveniently carried out by operators by embedding the mark, so that the thickness of a sprayed layer is determined; the arrangement of the sectional concrete spraying and the construction joint is beneficial to reducing the temperature stress and the structural stress generated in the concrete solidification forming process; and the concrete can reach the optimal strength through good maintenance, and the structural strength of the IV-class surrounding rock and the V-class surrounding rock is enhanced.
The present invention in a preferred example may be further configured to: in the process of pouring the lining structure,
selecting phi 18 steel bars as reinforcing steel bars, welding the reinforcing steel bars to form reinforcing mesh, wherein the longitude and latitude distances of the reinforcing mesh are all 50-80cm, the reinforcing mesh and the surrounding rock support form a reinforcing steel bar protective layer, and the thickness of the reinforcing steel bar protective layer is 5 cm;
when the concrete is pumped to a corresponding position by using a concrete delivery pump, a 50-type vibrating rod is used for vibrating, so that the concrete can be filled in the corresponding position;
when concrete at the position of the top arch is poured, a pump pipe needs to be buried at a top template, a concrete pumping hose is connected to the pump pipe, the erection is firm, the concrete pumping hose is disassembled when the top is basically full and feeding cannot be carried out, the top template is disassembled when the top arch concrete is cured to 50% of strength, the pump pipe and the concrete in the pump pipe are chiseled, and the surface is coated with high-strength waterproof mortar powder;
after the concrete is poured and the template is removed, watering maintenance needs to be carried out on the surface of the concrete to ensure that the surface of the concrete is wet.
By adopting the technical scheme, phi 18 steel is thick enough, the single body has strong bearing capacity, and the reinforcing steel bars are woven into the reinforcing steel bar mesh, so that the structural strength of the lining structure can be effectively enhanced in the transverse and longitudinal directions, and the lining structure is not easy to crack; the vibrating process is helpful for ensuring the compact and seamless lining structure after forming; the bearing pressure of the top of the lining structure is large, when concrete is fixedly poured, the pump pipe is directly poured in a burying mode, so that the concrete at the top of the lining structure is more compact, and the grooves chiseled off the pump pipe can be leveled again by using high-strength waterproof mortar for powder surface.
The present invention in a preferred example may be further configured to: the backfill grouting process comprises the following construction steps:
step one, arrangement of backfill grouting holes, wherein 3 holes, two side holes and one top hole are arranged in each row within the range of a hole top central angle of 90-120 degrees, and the row distance is 3.0 m;
step two, arranging a grouting system: arranging a grouting construction platform and a track at the position of the bottom plate in the hole, and sending grouting materials and mechanical equipment into the hole for standby;
step three, grouting a subarea: the top arch backfill grouting is carried out in sections, and the length of each section is not more than 50 m;
step four, drilling: obtaining a backfill grouting hole by adopting a pneumatic drilling hole forming technology, wherein the section diameter of the backfill grouting hole is not less than 38 mm;
step five, grouting: in the backfill grouting process, a dial gauge is required to be installed at the backfill grouting part to carry out deformation observation on the lining until grouting is finished;
step six, hole sealing: and after the backfill grouting is finished, sealing the backfill grouting hole by using a mechanical grouting hole sealing method, and after the backfill grouting hole is solidified, cleaning the unsealed hole section and then sealing the backfill grouting hole by using cement mortar.
By adopting the technical scheme, the backfill grouting mainly aims at filling the gap between the top of the lining structure and surrounding rocks, so that the main grouting parts are all arranged at the top of the hole, and the installation of the dial indicator for carrying out deformation observation on the lining is favorable for avoiding the damage to the lining structure caused by overlarge pressure of pressure grouting; and after grouting, hole sealing is carried out to avoid backflow of slurry, so that the slurry can be effectively condensed.
The present invention in a preferred example may be further configured to: the consolidation grouting process comprises the following construction steps:
step one, drilling arrangement: the consolidation grouting holes are distributed with 6 holes at equal intervals along the central angle of 60 degrees of the section of the bottom hole, wherein the 6 holes are respectively a bottom hole, two top edge holes, two bottom edge holes and a top hole, and the top edge hole and the top hole at the top can be deepened to the designed hole depth by using the original backfilling grouting hole; the drill hole can be drilled by a pneumatic air leg type rock drilling machine matched with a hexagonal drill rod or an alloy drill bit in a wet mode, and the hole diameter is 38-50 mm;
step two, drilling and flushing: after drilling is finished, drilling and crack flushing are carried out, single-hole or group-hole flushing is adopted according to the grouting sequence, the crack flushing pressure is 80% of the grouting pressure, and the process can be finished after backwater is clarified and lasts for 10 minutes;
step three, grouting: consolidation grouting is carried out according to the sequence of the bottom hole, the two top edge holes, the two bottom edge holes and the top hole; during grouting, a dial indicator is arranged at the position of the lining for deformation observation, the slurry suction amount in unit time is not more than 0.4L/min when the consolidation grouting reaches the design pressure, and the standard that the slurry is not sucked can be considered to be reached after 30min is prolonged.
Step four, hole sealing: and after the grouting hole reaches the end standard, sealing the hole by a mechanical grouting hole sealing method, and after the grouting hole is solidified, cleaning the unsealed part and then leveling by using cement mortar.
By adopting the technical scheme, the main function of consolidation grouting is to enhance the structural strength of IV-type and V-type surrounding rocks, so grouting treatment needs to be carried out in the circumferential direction of the tunnel, a better reinforcement effect is achieved, the consolidation grouting holes need to be washed by water before consolidation grouting, and the consolidation grouting effect is enhanced because the grouting holes can absorb more dense slurry.
The present invention in a preferred example may be further configured to: the lining structure of tunnel need set up a construction joint every 50m, be provided with the copper sheet waterstop in the construction joint, the copper sheet waterstop presss from both sides in the template before the lining is pour, treats that the lining structure is poured the back that finishes, and the copper sheet waterstop is even as an organic whole with the lining structure.
Through adopting above-mentioned technical scheme, the setting of construction joint is favorable to avoiding the concrete of lining structure to lead to the fracture because stress is too big when the concretion shaping to, the cooperation of construction joint and copper sheet waterstop can certain extent will ooze the infiltration and drain away, avoids the infiltration to the destruction of lining structure.
The second purpose of the invention is realized by the following technical scheme: IV type, V type country rock tunnel concrete lining anti-crack structure, including the country rock and be used for strutting the lining of country rock, still include the catch basin that tunnel face slope summit was seted up, the country rock with step top position between be provided with backfill grout layer, the country rock is being provided with permanent supporting construction near step circumference position department, the country rock is provided with the consolidation grout layer for the 1.5m circumference position department at the degree of depth.
Through adopting above-mentioned technical scheme, the tunnel can be kept away from in the intercepting ditch with a large amount of precipitation guides, and permanent supporting construction can strengthen the structural strength that the country rock is close to the lining structure position, backfills the grout blanket and can improve the bearing capacity of lining structure to the hole top department, concreties the grout blanket and can improve the structural strength of tunnel in deep position department.
In summary, the invention includes at least one of the following beneficial technical effects:
firstly, the structural strength of the IV-type and V-type surrounding rocks is improved to a greater extent, and the lining structure is prevented from being damaged due to more seepage water leaking to the lining structure;
secondly, the reinforcing mesh arranged in the lining structure improves the structural strength of the lining structure;
thirdly, the intercepting drain can keep away from the tunnel with a large amount of precipitation guide, has reduced the infiltration to the destruction of structure of lining.
Drawings
FIG. 1 is a view showing the overall construction steps of example 1;
FIG. 2 is a view showing the construction steps of the anchor bolt support in example 1;
FIG. 3 is a construction step diagram of a process for casting a lining structure in example 1;
FIG. 4 is a view showing the construction steps of backfill grouting according to example 1;
FIG. 5 is a view showing the construction steps of the consolidation grouting in example 1;
FIG. 6 is a drawing showing the construction steps of the shotcrete support in example 1;
FIG. 7 is a schematic view of the entire structure of embodiment 2.
In the figure: 1. surrounding rocks; 2. lining; 2a, side walls; 2b, a top arch; 3. a base plate; 4. backfilling a grouting layer; 5. and (5) solidifying the grouting layer.
Detailed Description
The invention is described in detail below with reference to the figures and examples.
In which like parts are designated by like reference numerals. It should be noted that the present invention relates to technical terms such as "concrete", "pouring", "grouting", "crown", "cave face", "axillary angle", "curing", "strength", etc., and those skilled in the art can understand the specific meanings of the above terms in the present invention according to specific situations.
Example 1
Referring to fig. 1, the concrete lining anti-cracking construction method for the IV-type and V-type surrounding rock tunnels comprises the following steps:
step one, erecting a waterproof structure: the method comprises the steps that a catch basin is arranged at the top of a side slope of a tunnel face, specifically, the width and the depth of the catch basin are both 0.6m, in other embodiments, the width of the catch basin can be any value of 0.6-1.2m, and the depth of the catch basin can be any value of 0.6-1 m;
step two, erecting a supporting structure: erecting a permanent supporting structure at the surrounding rock of the tunnel, erecting a temporary supporting structure in the tunnel, wherein the permanent supporting structure adopts a bolt support, the temporary supporting structure is a steel arch, and because the tunnel is longer and the grades of surrounding rocks of all sections of the tunnel are different, the circumferential angle of laying the steel arch at the IV-type surrounding rock in the tunnel is 240 +/-2 degrees, and the circumferential angle of laying the steel arch at the V-type surrounding rock is 289 +/-2 degrees;
step three, pouring a lining structure: laying steel bars according to the sequence of the bottom plate, the side wall and the top arch, then laying a template by using a needle beam hydraulic self-propelled trolley, finally pouring according to the sequence of the bottom plate, the side wall and the top arch by using a concrete delivery pump, and removing the template after pouring and curing;
step four, backfilling and grouting: arranging a backfill grouting hole in the position of 10cm of the depth of the surrounding rock, starting backfill grouting when the lining reaches 70% strength, and continuing grouting for 5min and stopping backfill grouting when the grouting pressure reaches 0.4-0.6Mpa and the backfill grouting hole stops sucking grout;
step five, consolidation grouting: and 7 days after backfilling and grouting, arranging a consolidation grouting hole at the depth of the surrounding rock not less than 1.5m, starting consolidation grouting, and stopping grouting when the grouting pressure reaches 2.3-2.8Mpa and the consolidation grouting hole does not absorb grout any more.
Referring to fig. 2, the bolting comprises the following specific construction steps:
step one, drilling: drilling by adopting a pneumatic drilling pore-forming technology to obtain an anchor rod mounting hole, wherein the aperture phi of the anchor rod mounting hole is 42mm, the hole depth is 1.5m, the position of the anchor rod mounting hole is arranged along the cross-section circle of the tunnel, one anchor rod mounting hole is arranged at the circumferential angle position of every 10 degrees of the cross-section circle from the position of an axillary angle, the anchor rod mounting hole is not arranged at the position of a bottom plate, the deviation of the hole position is not more than 100mm, and the deviation of the hole depth is not more than 50; after the anchor rod mounting hole is formed, high-pressure air is used for cleaning the hole;
step two, anchor rod installation: cutting an anchor rod into 1.5m, removing rust, conveying anchoring mortar into an anchor rod mounting hole through a grouting pump, enabling the pipe orifice of a mortar conveying pipe inserted into the anchor rod mounting hole to be 5-10 cm away from the hole bottom, discharging the mortar conveying pipe after the anchoring mortar flows out of the orifice, and finally inserting the anchor rod;
wherein, the anchor rod material is deformed steel bar with phi 25 specification; the anchoring mortar of the grouting anchor rod is prepared by mixing anchoring cement and anchoring sand, wherein the anchoring cement of the embodiment adopts 32.5Mpa common Portland cement, and the anchoring sand adopts hard and clean medium-fine sand with the particle size of 2.5 mm.
Referring to fig. 3, in the process of pouring the lining structure, the overall construction steps are as follows:
step one, steel bar erection: the method comprises the following steps of laying steel bars according to the sequence of a bottom plate, a side wall and a top arch, wherein the steel bars are made of phi 18 steel, and the steel bars are welded to form a steel bar mesh, the longitude and latitude distances of the steel bar mesh in the embodiment are 50cm, in other embodiments, the longitude and latitude distances of the steel bar mesh can be any value between 50cm and 80cm, the steel bar mesh and a surrounding rock support form a steel bar protective layer, and the thickness of the steel bar protective layer is 5 cm;
step two, erecting a template: then, a needle beam hydraulic self-propelled trolley is used for laying the template;
step three, concrete pouring: concrete is poured by using a concrete delivery pump, the pouring sequence is a bottom plate, a side wall and a top arch, when the concrete is pumped to a corresponding position by using the concrete delivery pump, a 50-type vibrating bar is used for vibrating, and the concrete can be ensured to be filled in the corresponding position; when concrete at the position of the top arch is poured, a pump pipe needs to be buried at a top template, a concrete pumping hose is connected to the pump pipe, the erection is firm, the concrete pumping hose is disassembled when the top is basically full and feeding cannot be carried out, the top template is disassembled when the top arch concrete is cured to 50% of strength, the pump pipe and the concrete in the pump pipe are chiseled, and the surface is coated with high-strength waterproof mortar powder; after the concrete is poured and the template is removed, watering maintenance needs to be carried out on the surface of the concrete to ensure that the surface of the concrete is wet;
step four, maintenance: after the concrete is poured and the template is removed, watering maintenance needs to be carried out on the surface of the concrete to ensure that the surface of the concrete is wet.
Referring to fig. 4, the backfill grouting process comprises the following construction steps:
step one, arrangement of backfill grouting holes, wherein 3 holes, two side holes and one top hole are arranged in each row within the range of a hole top central angle of 90-120 degrees, and the row distance is 3.0 m;
step two, arranging a grouting system: arranging a grouting construction platform and a track at the position of the bottom plate in the hole, and sending grouting materials and mechanical equipment into the hole for standby;
step three, grouting a subarea: the top arch backfill grouting is carried out in sections, and the length of each section is not more than 50 m;
step four, drilling: obtaining a backfill grouting hole by adopting a pneumatic drilling hole forming technology, wherein the section diameter of the backfill grouting hole is not less than 38 mm;
step five, grouting: in the backfill grouting process, a dial gauge is required to be installed at the backfill grouting part to carry out deformation observation on the lining until grouting is finished;
step six, hole sealing: and after the backfill grouting is finished, sealing the backfill grouting hole by using a mechanical grouting hole sealing method, and after the backfill grouting hole is solidified, cleaning the unsealed hole section and then sealing the backfill grouting hole by using cement mortar.
Referring to fig. 5, the consolidation grouting process includes the following construction steps:
step one, drilling arrangement: arranging 1 hole at intervals of 60 degrees along the central angle of the section of the bottom hole in the consolidation grouting hole arrangement holes, arranging 6 holes at equal intervals, namely the bottom hole, two top edge holes, two bottom edge holes and a top hole, wherein the top edge hole and the top hole at the top can be deepened to the designed hole depth by using a backfill grouting original hole; the drill hole can be drilled by a pneumatic air leg type rock drilling machine matched with a hexagonal drill rod or an alloy drill bit in a wet mode, and the hole diameter is 38-50 mm;
step two, drilling and flushing: after drilling is finished, drilling and crack flushing are carried out, single-hole or group-hole flushing is adopted according to the grouting sequence, the crack flushing pressure is 80% of the grouting pressure, and the process can be finished after backwater is clarified and lasts for 10 minutes;
step three, grouting: consolidation grouting is carried out according to the sequence of the bottom hole, the two top edge holes, the two bottom edge holes and the top hole; during grouting, a dial indicator is arranged at the position of the lining for deformation observation, the slurry suction amount in unit time is not more than 0.4L/min when the consolidation grouting reaches the design pressure, and the standard that the slurry is not sucked can be considered to be reached after 30min is prolonged.
Step four, hole sealing: and after the grouting hole reaches the end standard, sealing the hole by a mechanical grouting hole sealing method, and after the grouting hole is solidified, cleaning the unsealed part and then leveling by using cement mortar.
The lining structure of the tunnel needs to be provided with a construction joint every 50m, a copper sheet waterstop is arranged in the construction joint, the copper sheet waterstop is clamped in a template before the lining is poured, and after the lining structure is poured, the copper sheet waterstop and the lining structure are connected into a whole.
Example 2
The construction method of this embodiment is basically the same as that of embodiment 1, except that the present embodiment employs a shotcrete support instead of a bolt support.
Referring to fig. 6, the shotcrete support comprises the following construction steps:
step one, cleaning: before the spraying construction, pumice on the sprayed surface of the tunnel is removed, the sprayed surface is washed by wind and water, and the rock stratum which is easy to soften when meeting water is cleaned by compressed air;
step two, embedding a mark: burying a thickness mark at the surrounding rock so as to control and check the thickness of the sprayed layer;
step three, spraying: spraying in sections according to a section form of 10-20 m, and forming a work seam between sections;
step four, maintenance: and (3) after the sprayed concrete is finally set for 2h, performing air-water curing by using a spraying machine, curing by using a film when the ambient temperature is lower than 5 ℃, and building a lining structure after curing for 7 days.
Example 3
Referring to fig. 7, a concrete lining anti-cracking structure for a type iv or type v surrounding rock tunnel is built by the method of embodiment 1 or embodiment 2, and includes a surrounding rock 1, a lining 2 for supporting the surrounding rock 1, and a bottom plate 3 for better construction, where the lining 2 may be divided into a side wall 2a and a crown 2b according to positions, and further includes a cut-off ditch (not shown in the figure) formed at the top of a slope of a face side of the tunnel, the radius of the tunnel in this embodiment is 2m, in other embodiments, the radius of the tunnel may be drilled according to actual needs, a backfill grouting layer 4 is provided between the surrounding rock 1 and the top of the lining 2, the surrounding rock 1 is provided with a permanent support structure (not shown in the figure) at a position near the circumferential direction of the lining 2, and the surrounding rock 1 is provided with a consolidation grouting layer 5 at a circumferential position with a depth of 1.5 m.
The above description is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiment, and all technical solutions belonging to the idea of the present invention belong to the protection scope of the present invention. It should be noted that modifications and embellishments within the scope of the invention may occur to those skilled in the art without departing from the principle of the invention, and are considered to be within the scope of the invention.
Claims (10)
1. The IV-type and V-type surrounding rock tunnel concrete lining anti-cracking construction method is characterized by comprising the following steps of:
step one, erecting a waterproof structure: arranging a catch basin at the top of the tunnel face side slope;
step two, erecting a supporting structure: erecting a permanent supporting structure at the surrounding rock of the tunnel, and erecting a temporary supporting structure in the tunnel, wherein the permanent supporting structure adopts one of anchor bolt supporting and concrete injection supporting, and the temporary supporting structure is a steel arch frame;
step three, pouring a lining structure: laying steel bars according to the sequence of the bottom plate, the side wall and the top arch, then laying a template by using a needle beam hydraulic self-propelled trolley, finally pouring according to the sequence of the bottom plate, the side wall and the top arch by using a concrete delivery pump, and removing the template after pouring and curing;
step four, backfilling and grouting: arranging a backfill grouting hole in the position of 10cm of the depth of the surrounding rock, starting backfill grouting when the lining reaches 70% strength, and continuing grouting for 5min and stopping backfill grouting when the grouting pressure reaches 0.4-0.6Mpa and the backfill grouting hole stops sucking grout;
step five, consolidation grouting: and 7 days after backfilling and grouting, arranging a consolidation grouting hole at the depth of the surrounding rock not less than 1.5m, starting consolidation grouting, and stopping grouting when the grouting pressure reaches 2.3-2.8Mpa and the consolidation grouting hole does not absorb grout any more.
2. The IV-type and V-type surrounding rock tunnel concrete lining anti-cracking construction method according to claim 1, characterized in that: the width of the intercepting ditch is 0.6-1.2m, and the depth is 0.6-1 m.
3. The IV-type and V-type surrounding rock tunnel concrete lining anti-cracking construction method according to claim 1, characterized in that: the circumferential angle of laying of the steel arch centering of IV type country rock department in the tunnel is 240 +/-2 degrees, the circumferential angle of laying of the steel arch centering of V type country rock department is 289 +/-2 degrees.
4. The IV-type and V-type surrounding rock tunnel concrete lining anti-cracking construction method according to claim 1, wherein the anchor bolt support comprises the following construction steps:
step one, drilling: drilling by adopting a pneumatic drilling pore-forming technology to obtain an anchor rod mounting hole, wherein the aperture phi of the anchor rod mounting hole is 42mm, the hole depth is 1.5m, the position of the anchor rod mounting hole is arranged along the cross-section circle of the tunnel, one anchor rod mounting hole is arranged at the circumferential angle position of every 10 degrees of the cross-section circle from the position of an axillary angle, the anchor rod mounting hole is not arranged at the position of a bottom plate, the deviation of the hole position is not more than 100mm, and the deviation of the hole depth is not more than 50; after the anchor rod mounting hole is formed, high-pressure air is used for cleaning the hole;
step two, anchor rod installation: cutting an anchor rod into 1.5m, removing rust, conveying anchoring mortar into an anchor rod mounting hole through a grouting pump, enabling the pipe orifice of a mortar conveying pipe inserted into the anchor rod mounting hole to be 5-10 cm away from the hole bottom, discharging the mortar conveying pipe after the anchoring mortar flows out of the orifice, and finally inserting the anchor rod;
wherein, the anchor rod material is deformed steel bar with phi 25 specification; the anchoring mortar for grouting anchor rod is prepared by mixing anchoring cement and anchoring sand, wherein the anchoring cement is ordinary Portland cement of over 32.5Mpa, and the anchoring sand is hard and clean medium-fine sand with particle size less than 2.5 mm.
5. The IV-type and V-type surrounding rock tunnel concrete lining anti-cracking construction method according to claim 1, wherein the injection concrete support comprises the following construction steps:
step one, cleaning: before the spraying construction, pumice on the sprayed surface of the tunnel is removed, the sprayed surface is washed by wind and water, and the rock stratum which is easy to soften when meeting water is cleaned by compressed air;
step two, embedding a mark: burying a thickness mark at the surrounding rock so as to control and check the thickness of the sprayed layer;
step three, spraying: spraying in sections according to a section form of 10-20 m, and forming a work seam between sections;
step four, maintenance: and after the sprayed concrete is finally set for 2h, performing air-water curing by using a spraying machine, and curing by using a film when the ambient temperature is lower than 5 ℃.
6. The IV-type and V-type surrounding rock tunnel concrete lining anti-cracking construction method according to claim 1, characterized in that: in the process of pouring the lining structure,
selecting phi 18 steel bars as reinforcing steel bars, welding the reinforcing steel bars to form reinforcing mesh, wherein the longitude and latitude distances of the reinforcing mesh are all 50-80cm, the reinforcing mesh and the surrounding rock support form a reinforcing steel bar protective layer, and the thickness of the reinforcing steel bar protective layer is 5 cm;
when the concrete is pumped to a corresponding position by using a concrete delivery pump, a 50-type vibrating rod is used for vibrating, so that the concrete can be filled in the corresponding position;
when concrete at the position of the top arch is poured, a pump pipe needs to be buried at a top template, a concrete pumping hose is connected to the pump pipe, the erection is firm, the concrete pumping hose is disassembled when the top is basically full and feeding cannot be carried out, the top template is disassembled when the top arch concrete is cured to 50% of strength, the pump pipe and the concrete in the pump pipe are chiseled, and the surface is coated with high-strength waterproof mortar powder;
after the concrete is poured and the template is removed, watering maintenance needs to be carried out on the surface of the concrete to ensure that the surface of the concrete is wet.
7. The IV-type and V-type surrounding rock tunnel concrete lining anti-cracking construction method according to claim 1, wherein the backfill grouting process comprises the following construction steps:
step one, arrangement of backfill grouting holes, wherein 3 holes, two side holes and one top hole are arranged in each row within the range of a hole top central angle of 90-120 degrees, and the row distance is 3.0 m;
step two, arranging a grouting system: arranging a grouting construction platform and a track at the position of the bottom plate in the hole, and sending grouting materials and mechanical equipment into the hole for standby;
step three, grouting a subarea: the top arch backfill grouting is carried out in sections, and the length of each section is not more than 50 m;
step four, drilling: obtaining a backfill grouting hole by adopting a pneumatic drilling hole forming technology, wherein the section diameter of the backfill grouting hole is not less than 38 mm;
step five, grouting: in the backfill grouting process, a dial gauge is required to be installed at the backfill grouting part to carry out deformation observation on the lining until grouting is finished;
step six, hole sealing: and after the backfill grouting is finished, sealing the backfill grouting hole by using a mechanical grouting hole sealing method, and after the backfill grouting hole is solidified, cleaning the unsealed hole section and then sealing the backfill grouting hole by using cement mortar.
8. The IV-type and V-type surrounding rock tunnel concrete lining anti-cracking construction method according to claim 7, characterized in that: the consolidation grouting process comprises the following construction steps:
step one, drilling arrangement: the consolidation grouting holes are distributed with 6 holes at equal intervals along the central angle of 60 degrees of the section of the bottom hole, wherein the 6 holes are respectively a bottom hole, two top edge holes, two bottom edge holes and a top hole, and the top edge hole and the top hole at the top can be deepened to the designed hole depth by using the original backfilling grouting hole; the drill hole can be drilled by a pneumatic air leg type rock drilling machine matched with a hexagonal drill rod or an alloy drill bit in a wet mode, and the hole diameter is 38-50 mm;
step two, drilling and flushing: after drilling is finished, drilling and crack flushing are carried out, single-hole or group-hole flushing is adopted according to the grouting sequence, the crack flushing pressure is 80% of the grouting pressure, and the process can be finished after backwater is clarified and lasts for 10 minutes;
step three, grouting: consolidation grouting is carried out according to the sequence of the bottom hole, the two top edge holes, the two bottom edge holes and the top hole; in the grouting process, a dial indicator is arranged at the position of the lining for deformation observation, the slurry suction amount in unit time is not more than 0.4L/min when the consolidation grouting reaches the design pressure, and the standard that the slurry is not sucked can be considered to be reached after 30min is prolonged;
step four, hole sealing: and after the grouting hole reaches the end standard, sealing the hole by a mechanical grouting hole sealing method, and after the grouting hole is solidified, cleaning the unsealed part and then leveling by using cement mortar.
9. The IV-type and V-type surrounding rock tunnel concrete lining anti-cracking construction method according to claim 1, characterized in that: the lining structure of tunnel need set up a construction joint every 50m, be provided with the copper sheet waterstop in the construction joint, the copper sheet waterstop presss from both sides in the template before the lining is pour, treats that the lining structure is poured the back that finishes, and the copper sheet waterstop is even as an organic whole with the lining structure.
10. The utility model provides a IV class, V class country rock tunnel concrete lining anti-crack structure, includes country rock (1) and is used for strutting lining (2) of country rock (1), its characterized in that: still include the catch basin that tunnel face side slope summit was seted up, country rock (1) with step lining (2) top position between be provided with backfill grout blanket (4), country rock (1) is being close to step lining (2) circumference position department and is being provided with permanent supporting construction, country rock (1) is provided with consolidation grout blanket (5) for 1.5m circumference position department at the degree of depth.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN114215567A (en) * | 2021-12-17 | 2022-03-22 | 新疆额尔齐斯河流域开发工程建设管理局 | Construction method of V-type and IV-type surrounding rocks in ultra-long TBM tunnel |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN114215567A (en) * | 2021-12-17 | 2022-03-22 | 新疆额尔齐斯河流域开发工程建设管理局 | Construction method of V-type and IV-type surrounding rocks in ultra-long TBM tunnel |
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