A subway connecting passage corrugated steel initial support structure and a construction method thereof

Abstract

The application discloses a subway connecting passage corrugated steel initial support structure, a frozen wall is formed on the inner side of a surrounding rock excavation surface, the support structure is formed by two or more single corrugated steel plate members which are sequentially overlapped and assembled along the annular inner side wall of the frozen wall, the support structure is provided with a grouting hole, and the support structure seals the exposed surface of the frozen wall; the single corrugated steel plate member is formed by two or more corrugated steel plates which are sequentially overlapped; and a construction method of the support structure is also provided, which comprises the following steps: S1, excavating the soil of the connecting passage; S2, assembling the support structure of the single corrugated steel plate member to seal the exposed surface of the frozen wall; S3, arranging one circle of grouting holes for every three single corrugated steel plate members, and injecting low-heat-release high polymer grouting material; and S4, entering the excavation cycle after the grouting is completed. The subway connecting passage corrugated steel initial support structure and the construction method thereof are provided, the corrugated steel plate is used in the initial support structure, the low-heat-release high polymer polyurethane grouting material is injected, the concrete spraying operation process is cancelled, the excavation is carried out while the support is carried out in the excavation process, the working surface environment is improved, and safe construction is ensured.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of connection passage construction, in particular to a corrugated steel initial support structure for a subway connection passage and a construction method thereof. BACKGROUND

[0002] The freezing method is a method of artificially freezing water in the soil around the underground space to be excavated into ice and cementing it with the soil to form a frozen soil wall or a closed frozen soil body according to the design contour, which is used to resist the pressure of the soil, isolate the groundwater, and under the protection of the frozen soil wall, the construction of the underground project is carried out. First, the freezing pipe drilling positioning is carried out, after the drilling is completed, the freezing device is arranged in the freezing hole, the freezing pipe is installed, and the freezing pipe and the freezing system are connected with each other, and finally the freezing is carried out. The circulating cold quantity of the freezing pipe in the soil condenses the water in the soil into ice, so that the rock-soil becomes frozen soil, thereby achieving the purpose of enhancing the stability and strength of the soil, and forming a temporary reinforcement body with better integrity and better waterproof performance. The freezing and thawing will inevitably cause frost heaving and thawing settlement, and the frost heaving of the frozen soil generally has considerable thawing settlement, thereby causing uneven uplift or subsidence of the ground surface and causing the compaction settlement of the soil layer.

[0003] The connection passage is a connection passage connecting the uplink and downlink shield tunnels, and its main function is to ensure the disaster prevention and interval drainage needs of the shield tunnel in the operation period. At present, the construction of the connection passage in China mainly adopts the freezing method for stratum reinforcement and the mine tunneling method. Due to the construction of the foundation pit in the connection passage, the construction space is small, and the initial support is mainly in the form of "profile steel support + wood backboard + shotcrete" or "steel grid support + shotcrete". The construction sequence is: excavation → profile steel or steel grid support → shotcrete closure → excavation. The conversion time between the shotcrete operation, excavation and initial support installation process is long, the construction efficiency is low, and the site operation environment is poor after the shotcrete, which has high engineering risk. SUMMARY

[0004] Therefore, the technical problem to be solved by the present application is to provide a subway connection passage corrugated steel initial support structure which applies corrugated steel plates to the initial support structure of the subway connection passage freezing and uses low-heat-release high-polymer grouting material to improve the bonding force of the frozen wall, and cancels the shotcrete operation process. The transportation is convenient, the assembly is simple, the stacking is easy, the working face environment is improved, the engineering quality is improved, and the safe construction is ensured.

[0005] To solve the above technical problems, the present application provides the following technical solutions:

[0006] A subway connecting passage corrugated steel initial support structure, a frozen wall is formed on the inner side of the surrounding rock excavation surface, the support structure is formed by two or more single corrugated steel plate members which are sequentially spliced along the annular inner side wall of the frozen wall, the support structure is provided with a grouting hole, and the support structure seals the exposed surface of the frozen wall; the single corrugated steel plate member is formed by two or more corrugated steel plates which are sequentially spliced.

[0007] Further, the single corrugated steel plate member is formed by at least four corrugated steel plates which are sequentially connected by high-strength bolts to form a closed-loop structure adapted to the annular inner side wall of the frozen wall, and the longitudinal wall width of the single corrugated steel plate member is 500-800mm.

[0008] Further, the adjacent two corrugated steel plates among the at least four corrugated steel plates are spliced and connected by high-strength bolts, and the splicing length between the adjacent two corrugated steel plates is not less than 50mm.

[0009] Further, the adjacent two single corrugated steel plate members among the two or more single corrugated steel plate members are spliced and connected by high-strength bolts, and the splicing length between the adjacent two single corrugated steel plate members is not less than 100mm.

[0010] Further, the corrugated steel plate is made of Q345 steel material, the thickness of the corrugated steel plate is 5-10mm, the wave distance of the corrugated steel plate is 150-300mm, and the wave depth of the corrugated steel plate is 50-110mm.

[0011] Further, the single corrugated steel plate member is provided with four or more, and two or more grouting holes are uniformly arranged on every two adjacent single corrugated steel plate members, the spacing between the single corrugated steel plate members provided with the grouting holes is 1500-2400mm, and the grouting holes are connected with grouting pipes through seamless steel pipes.

[0012] Further, the grouting pipes inject low-heat high polymer grouting materials into the grouting holes to bond the frozen wall and the support structure.

[0013] Further, the density of the low-heat high polymer grouting material is 0.08-0.20g / cm 3 , the volume free expansion rate is 20-25 times, the viscosity is ≤500mPa·s, the surface reaction temperature is ≤40℃, and the thermal conductivity is ≤0.05W / (m·K), and the curing time is ≤15min.

[0014] The application discloses a construction method of a subway connecting passage corrugated steel initial support structure, a frozen wall is formed on the inner side of an excavation surface of surrounding rock, the support structure is formed by two or more single corrugated steel plate members which are sequentially spliced and connected along the annular inner side wall of the frozen wall, the support structure is provided with a grouting hole, and the support structure seals the exposed surface of the frozen wall; the single corrugated steel plate member is formed by two or more corrugated steel plates which are sequentially spliced and connected; and the construction method comprises the following steps:

[0015] S1, excavating the soil of the connecting passage at an excavation step distance of 500-800 mm, which is consistent with the width of the single corrugated steel plate member;

[0016] S2, after the soil excavation is completed, the single corrugated steel plate member is spliced in a sequence of from bottom to top, so that the support structure formed after splicing seals the exposed surface of the frozen wall;

[0017] S3, along the excavation direction, one grouting hole is arranged every three single corrugated steel plate members, the grouting hole is located on the third single corrugated steel plate member, and after the three single corrugated steel plate members are installed, the low-heat-release high polymer grouting material is injected into the space behind the corrugated steel plate through the grouting hole in a sequence from top to bottom, and the frozen wall, the corrugated steel plate and the low-heat-release high polymer grouting material are bonded to form a combined bearing;

[0018] S4, after the grouting is completed, the excavation, support and grouting cycle is entered in the sequence of S1-S3.

[0019] The technical scheme of the application achieves the following beneficial technical effects:

[0020] 1. Compared with the traditional connecting passage initial support form, the subway connecting passage corrugated steel initial support structure and the construction method thereof provided by the application have the advantages of reduced thickness, increased strength, higher toughness and simplified construction process.

[0021] 2. Compared with the traditional initial support form, the initial support thickness of the subway connecting passage corrugated steel initial support structure and the construction method thereof provided by the application is greatly reduced, the excavation section size can be reduced, the construction progress can be accelerated, and the construction risk can be reduced.

[0022] 3. The subway connecting passage corrugated steel initial support structure and the construction method thereof provided by the application adopt low-heat-release high polymer grouting material, continuously erode the frozen wall by means of local reaction heat, form micro-melting frozen channels on the frozen wall without affecting the strength of the frozen wall, enable the grouting material and the frozen wall to form a mutual inlay microstructure, thereby greatly improving the bonding force with the frozen wall, and after the high polymer material is completely reacted, the grouting hole is blocked, so that the grouting hole is in a closed state. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1A schematic diagram of the initial support structure of corrugated steel for a subway connecting passage according to the present invention;

[0024] Figure 2 yes Figure 1 A schematic diagram of the cross-section;

[0025] Figure 3 yes Figure 2 A partial schematic diagram;

[0026] Figure 4 Schematic diagram of the support structure of this invention;

[0027] Figure 5 A schematic diagram of the cross-section of a corrugated steel initial support structure for a subway connecting passage according to the present invention.

[0028] Figure 6 This invention provides a longitudinal section schematic diagram of a corrugated steel initial support structure for a subway connecting passage.

[0029] The reference numerals in the figure are: 1-corrugated steel plate; 2-frozen wall; 3-surrounding rock; 4-low exothermic polymer grouting material; 5-high-strength bolt; 6-grouting hole. Detailed Implementation

[0030] Example 1

[0031] Figure 1 This is a schematic diagram of the initial support structure of corrugated steel for a subway connecting passage according to the present invention. Figure 2 yes Figure 1 A cross-sectional schematic diagram. Figure 3 yes Figure 2 A partial schematic diagram of the cross-section in the middle. Figure 4 This is a plan view of the support structure. Figure 5 This is a schematic diagram of the cross-section of the connecting passage. Figure 6 This is a schematic diagram of the longitudinal section of the connecting passage.

[0032] This implementation example Figures 1-6 As shown, a corrugated steel initial support structure for a subway connecting passage is constructed by forming a frozen wall 2 on the inner side of the excavation face of the surrounding rock 3. The wall layer is reinforced by freezing within the tunnel, causing the soil around the connecting passage to freeze and form a high-strength, well-sealed frozen soil wall. Then, a mining-like method is used to excavate and construct the connecting passage within the frozen soil wall, with support provided as excavation progresses. During the freezing process, the tunnel is subjected to frost heave forces, which cause transverse cross-sectional deformation, thus affecting the ellipticity of the tunnel. To reduce this deformation, a prestressed support structure is installed inside the frozen tunnel to control the tunnel deformation.

[0033] The supporting structure is formed by sequentially splicing a plurality of single corrugated steel plate pieces along the annular inner side wall of the freezing wall 2, and the supporting structure seals the exposed surface of the freezing wall 2. The single corrugated steel plate piece is formed by sequentially splicing four corrugated steel plates 1 through high-strength bolts 5. The single corrugated steel plate piece is a closed-loop structure that is adapted to the annular inner side wall of the freezing wall 2. The longitudinal wall width of the single corrugated steel plate piece is 500 mm, and the width of a single corrugated steel plate is 500 mm. Adjacent single corrugated steel plate pieces are spliced and connected by high-strength bolts 5 along the freezing wall in the excavated passage to form the supporting structure. The corrugated steel plate 1 is made of Q345 steel. The thickness of the corrugated steel plate 1 is 5 mm. The pitch of the corrugated steel plate 1 is 150 mm. The depth of the corrugated steel plate 1 is 50 mm. The splicing length between adjacent corrugated steel plates 1 is not less than 50 mm. The splicing length between adjacent single corrugated steel plate pieces is not less than 100 mm. The corrugated steel plate has high strength, good stress performance, and strong anti-deformation ability. The circular arch portions and the valleys of adjacent corrugated steel plates are correspondingly spliced and fixed vertically by high-strength bolts. The high-strength bolts are greater than grade 8.8 and are subjected to hot galvanizing corrosion protection. The top of the freezing wall in the passage is correspondingly spliced with a bent corrugated steel plate that is adapted to the shape of the wall top and has a circular arc transition with the top of the vertical corrugated steel plate. The bottom of the freezing wall in the passage is spliced with the bottom of the vertical corrugated steel plate at a circular arc transition, and the circular arc transition is fixed by a plurality of high-strength bolts arranged side by side.

[0034] The supporting structure is provided with uniformly arranged grouting holes 6. One circle of grouting holes is arranged every three pieces (with a spacing of 1500 mm). Two grouting holes are arranged on each corrugated steel plate. The grouting holes are generally φ45x3 mm seamless steel pipes as grouting pipes. The grouting holes are also used as thawing and sinking grouting holes after the construction of the secondary lining structure. The grouting holes are used to reduce the adverse effects of thawing and sinking on the passage, ground buildings, and underground pipelines, to timely track grouting, or to compensate for the stratum in a timely manner according to the observed passage and stratum settlement.

[0035] The single corrugated steel plate piece provided with the grouting holes is installed, and low-heat high-polymer grouting material is injected through the grouting pipe and the grouting hole to the space behind the corrugated steel plate in a timely manner, so that the freezing wall, the corrugated steel plate, and the low-heat high-polymer material are bonded to form a combined bearing.

[0036] The low-heat high-polymer grouting material is selected from the polyurethane grouting material in the prior art. The density of the grouting material ranges from 0.08 to 0.20 g / cm 3, the material viscosity is low, the injectability is good, the reaction temperature can be reduced, the influence of the material expansion force on the frozen wall and the corrugated steel plate is reduced, the volume free expansion rate is 20-25 times, the space of three single corrugated steel plate pieces can be quickly filled, the viscosity is less than 500 mPa·s, the injectability is good, the maximum surface reaction temperature is lower than 40 DEG C, the heat release temperature is low, the heat release amount is small, the influence of the heat release reaction on the outside frozen wall is reduced, the reaction temperature is low, the influence on the frozen wall is small, the thermal conductivity is less than 0.05 W / (m·K), the heat preservation effect is good, the solidification time is less than 15 min, the solidification reaction time can be adjusted, different environmental conditions can be adjusted, the reaction time is short, the filling and densification with the frozen wall and the corrugated steel plate can be completed in a short time, the adhesion is good, and the frozen wall and the corrugated steel plate can be combined into a whole.

[0037] The density of the grouting material is in the range of 0.08-0.20 g / cm 3 , the influence on the indicators of the grouting layer is small, the influence of the density: the greater the density of the polymer grouting material, the greater the corresponding center and surface maximum reaction temperature, and the greater the expansion force generated by the grouting material, mainly due to the increase of the reactant base concentration, the effective collision between the reactant molecules is increased, the maximum limit of the whole chemical reaction is improved, the heat release of the polymer solidification reaction is increased; the molecules have a large potential energy under the condition of high heat release, and the contact probability between the molecules is increased, resulting in an increase in the expansion force; when the density is greater than this range, the corresponding center and surface reaction temperature is greater, which has an adverse effect on the "hot melting" of the frozen wall, and the expansion force is greater, which has an adverse effect on the performance of the frozen wall and the corrugated steel plate; when the density is less than this range, the compressive and tensile strength of the material is significantly reduced, and the grouting layer may be damaged under the influence of external force.

[0038] The low-heat-release polymer grouting material of the embodiment selects polyurethane grouting material, and after mixing, a polyaddition reaction occurs to form a solidification process. The polyaddition process includes gelation reaction, foaming reaction and trimerization reaction. Since the three reactions are all exothermic reactions, a certain amount of heat will be released during the solidification process. Due to the heat release of the polymer solidification, the temperature difference between the polymer itself and the surrounding medium is increased. Since the frozen wall is sensitive to temperature, under the action of the temperature difference, the heat generated by the polymer solidification will enter the frozen wall through heat conduction, heat convection and heat radiation, and the reaction temperature is lower than 40 DEG C, which is not easy to cause heat accumulation, the influence of the self-heat effect on the surrounding environment is weak, and the influence range on the frozen wall temperature field is limited. The local reaction heat continuously erodes the frozen wall, forms a micro-melted frozen channel on the frozen wall, and makes the grouting material and the frozen wall form a mutual inlay structure, thereby improving the bonding force between the grouting material and the frozen wall.

[0039] A construction method of a subway connecting channel corrugated steel initial support structure, such as Figures 1-6As shown, a frozen wall 2 is formed on the inner side of the excavation face of the surrounding rock 3. The support structure is formed by assembling at least one single corrugated steel plate piece sequentially along the annular inner wall of the frozen wall 2. The support structure is provided with grouting holes 6, and the support structure seals the exposed surface of the frozen wall 2. The single corrugated steel plate piece is formed by assembling at least one corrugated steel plate 1 sequentially. The construction method includes the following steps:

[0040] S1. Excavate the soil for the connecting passage, with an excavation step distance of 500-800mm, and consistent with the width of a single corrugated steel plate.

[0041] S2. After the soil excavation is completed, the corrugated steel plate components are assembled in the order of bottom to top, so that the support structure formed after assembly closes the exposed surface of the frozen wall 2.

[0042] According to the design parameters, vertical side corrugated steel plates, arched top corrugated steel plates, and bottom corrugated steel plates with rounded ends are prefabricated off-site. Each corrugated steel plate has the same width (500mm), the same thickness (5mm), the same wave pitch (150mm), and the same wave depth (50mm). Its longitudinal length is determined based on measurements of the various longitudinal lengths of the frozen wall. At least two side corrugated steel plates, at least one top corrugated steel plate, and at least one bottom corrugated steel plate are aligned with each other. They should be overlapped and fixed with high-strength bolts to form a closed ring structure that fits the inner side wall of the frozen wall, becoming a single corrugated steel plate component. The overlap length between the corrugated steel plates of each circumferential single corrugated steel plate component should not be less than 50mm, and the overlap length between the corrugated steel plates of each single corrugated steel plate component in the longitudinal direction should not be less than 100mm. Moreover, the overlap positions in the longitudinal direction extending along the channel depth are different, that is, the adjacent single closed rings overlap in a staggered manner.

[0043] S3. Along the excavation direction, a ring of grouting holes 6 is set for every 3 individual corrugated steel plates. After the 3 individual corrugated steel plates are installed, low heat release polymer grouting material 4 is injected into the space behind the corrugated steel plate 1 through the grouting holes 6 in order from top to bottom. The frozen wall 2, corrugated steel plate 1 and low heat release polymer grouting material 4 are bonded together to form a joint load.

[0044] The grouting volume of each grouting hole shall not exceed 50L. Grouting shall be carried out in the order of bottom corrugated steel plate - side corrugated steel plate - top corrugated steel plate until grout overflows from the top grouting hole. After the polymer grouting material has fully reacted, the grouting hole opening will be sealed, so that the grouting hole is in a closed state. After the area between the three individual corrugated steel plates and the frozen soil wall is filled with grout, under the continuous action of grouting pressure and material expansion force, the grout will continue to expand and diffuse along the interior until the entire area is filled.

[0045] S4, after the grouting is completed, entering the cycle of excavation, support and grouting according to the sequence of S1-S3, obtaining a support structure. Obviously, the above embodiments are only examples for clearly illustrating, but not limitation to the embodiments. Based on the above description, other different forms of changes or variations can be made by those skilled in the art. Here, it is not necessary and also impossible to enumerate all the embodiments. The obvious changes or variations derived therefrom are still within the protection scope of the patent application claims.

Claims

1. A subway connecting passage corrugated steel initial support structure, characterized in that, The freezing wall (2) is formed on the inside of the surrounding rock (3) excavation face, the support structure is formed by two or more single corrugated steel plate members which are sequentially assembled along the annular inside wall of the freezing wall (2), the support structure is provided with a grouting hole (6), and the support structure seals the exposed surface of the freezing wall (2); the single corrugated steel plate member is formed by two or more corrugated steel plates (1) which are sequentially assembled; The single corrugated steel plate member is formed by at least four corrugated steel plates (1) which are sequentially connected by high-strength bolts (5) to form a closed loop structure which is adapted to the annular inside wall of the freezing wall (2), and the longitudinal wall width of the single corrugated steel plate member is 500-800mm; The corrugated steel plate (1) is made of Q345 steel, the thickness of the corrugated steel plate (1) is 5-10mm, the wave distance of the corrugated steel plate (1) is 150-300mm, and the wave depth of the corrugated steel plate (1) is 50-110mm; The grouting pipe injects low-heat high polymer grouting material (4) into the grouting hole (6) to bond the freezing wall (2) and the support structure.

2. A corrugated steel primary support structure for a subway crossover tunnel according to claim 1, characterised in that, The adjacent two corrugated steel plates (1) in the at least four corrugated steel plates (1) are assembled and connected by high-strength bolts (5), and the overlap length between the adjacent two corrugated steel plates (1) is not less than 50mm.

3. A corrugated steel primary support structure for a subway crossover tunnel according to claim 1, characterised in that, The adjacent two single corrugated steel plate members in the two or more single corrugated steel plate members are assembled and connected by high-strength bolts (5), and the overlap length between the adjacent two single corrugated steel plate members is not less than 100mm.

4. A corrugated steel primary support structure for a subway crossover tunnel according to claim 1, characterized in that, The single corrugated steel plate member is provided with four or more, and two or more grouting holes (6) are uniformly arranged on every other single corrugated steel plate member, the spacing between the single corrugated steel plate members provided with the grouting holes (6) is 1500-2400mm, and the grouting holes (6) are connected with grouting pipes through seamless steel pipes.

5. A corrugated steel primary support structure for a subway crossover tunnel according to claim 4, characterised in that, The low-heat high polymer grouting material (4) has a density of 0.08-0.20 g / cm 3 , a volume free expansion rate of 20-25 times, a viscosity of ≤500 mPa·s, a surface reaction temperature of ≤40℃, a thermal conductivity of ≤0.05 W / (m·K), and a curing time of ≤15 min.

6. The construction method of corrugated steel initial support structure of subway connecting passage, characterized in that, The freezing wall (2) is formed on the inside of the surrounding rock (3) excavation face, the support structure is formed by two or more single corrugated steel plate members which are sequentially assembled along the annular inside wall of the freezing wall (2), the support structure is provided with a grouting hole (6), and the support structure seals the exposed surface of the freezing wall (2); the single corrugated steel plate member is formed by two or more corrugated steel plates (1) which are sequentially assembled; and the construction method comprises the following steps: S1, excavate the soil of the connecting channel, the excavation step distance is 500-800mm, and is consistent with the width of the single corrugated steel plate member; S2, after the soil excavation is completed, sequentially assemble the single corrugated steel plate member in the order of first down and then up, so that the support structure formed after assembly seals the exposed surface of the freezing wall (2); S3, along the excavation direction, one circle of grouting holes (6) is arranged every three single corrugated steel plate members, the grouting holes (6) are located on the third single corrugated steel plate member, and after the three single corrugated steel plate members are installed, low-heat high polymer grouting material (4) is sequentially injected into the space behind the corrugated steel plate (1) through the grouting holes (6) in the order from top to bottom, and the freezing wall (2), the corrugated steel plate (1) and the low-heat high polymer grouting material (4) are bonded to form a combined bearing; S4, after grouting is completed, enter the excavation, support and grouting cycle in the order of S1-S3.

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