Methods for pouring large-volume concrete in the backfill area of ​​soft rock tunnels

Abstract

This invention discloses a method for pouring large-volume concrete in the backfill area of ​​a soft rock tunnel, relating to the field of soft rock tunnel construction technology. The method includes stabilizing the backfill area to form a reinforced zone; roughening the soft rock interface within the reinforced zone to form a surface to be poured; dividing the surface to be poured into multiple continuous pouring units according to a spiral path; and pouring concrete layer by layer into the multiple pouring units to complete the large-volume concrete pouring construction of the soft rock tunnel backfill area. This invention, through stabilization treatment to form a reinforced zone, targeted roughening of the soft rock interface, and layered concrete pouring using a spiral path, improves the bonding strength between the soft rock and concrete interface, thereby enhancing the long-term stability of the tunnel structure.

Description

Technical Field

[0001] This invention relates to the field of soft rock tunnel construction technology, and in particular to a method for pouring large-volume concrete in the backfill area of ​​a soft rock tunnel. Background Technology

[0002] In existing technologies, the pouring of large-volume concrete in the backfill area of ​​soft rock tunnels faces the challenges of insufficient interfacial bonding strength and potential structural instability.

[0003] When using traditional methods of horizontal or sloping layered pouring, the interface between soft rock and concrete is not adequately treated, resulting in weak bonding between the two. Furthermore, the continuous deformation of soft rock under concrete load is not effectively controlled, easily leading to stress concentration and structural cracking. For example, in a tunnel project, after using conventional layered pouring, delamination occurred at the interface between concrete and soft rock, and localized stress redistribution caused deformation of the lining structure. Summary of the Invention

[0004] The main objective of this invention is to propose a method for pouring large-volume concrete in the backfill area of ​​soft rock tunnels, which aims to improve the bonding strength between soft rock and concrete and enhance the long-term stability of the tunnel structure.

[0005] To achieve the above objectives, the present invention proposes a method for pouring large-volume concrete in the backfill area of ​​soft rock tunnels, comprising:

[0006] The soft rock tunnel backfill area is stabilized to form a reinforced zone;

[0007] The soft rock interface in the reinforced area is roughened to form a surface to be poured.

[0008] The surface to be poured is divided into multiple continuous pouring units according to a spiral path;

[0009] Concrete is poured in layers and sequentially into multiple pouring units to complete the large-volume concrete pouring construction of the soft rock tunnel backfill area.

[0010] In one embodiment, the step of roughening the soft rock interface within the reinforced zone to form the surface to be poured includes:

[0011] Hardness tests were performed on the soft rock interface within the reinforced area to obtain the hardness distribution.

[0012] Based on the hardness distribution, the soft rock interface is divided into multiple different treatment zones;

[0013] The soft rock interfaces in multiple different treatment areas are roughened to form the surface to be poured.

[0014] In one embodiment, the step of dividing the soft rock interface into multiple different treatment zones according to the hardness distribution includes:

[0015] The region in the soft rock interface that meets the first hardness range value is divided into the first sub-processing region;

[0016] The region in the soft rock interface that meets the second hardness range value is divided into the second sub-processing region;

[0017] The region in the soft rock interface that meets the third hardness range value is divided into the third sub-processing region;

[0018] Wherein, the first hardness range value is greater than the second hardness range value, and the second hardness range value is greater than the third hardness range value.

[0019] In one embodiment, the step of roughening the soft rock interface in multiple different treatment areas to form the surface to be poured includes:

[0020] The surface of the soft rock interface corresponding to the first sub-processing area is roughened to a first roughening depth.

[0021] The surface of the soft rock interface corresponding to the second sub-processing area is rinsed, and the surface of the soft rock interface corresponding to the second sub-processing area is roughened to a second roughening depth.

[0022] The surface of the soft rock interface corresponding to the third sub-processing area is cleaned and leveled to form the surface to be poured.

[0023] Wherein, the first chiseling depth is greater than the second chiseling depth.

[0024] In one embodiment, the step of dividing the surface to be poured into multiple consecutive pouring units according to a spiral path includes:

[0025] A spiral path is formed by extending outward from the geometric center of the surface to be poured.

[0026] In one embodiment, the pitch of the helix located in the first sub-processing region is greater than the pitch of the helix located in the second sub-processing region, and the pitch of the helix located in the second sub-processing region is greater than the pitch of the helix located in the third sub-processing region.

[0027] In one embodiment, the steps of pouring concrete in layers and sequentially into multiple pouring units to complete the large-volume concrete pouring construction of the soft rock tunnel backfill area include:

[0028] Concrete is poured into multiple pouring units according to the spiral path to form the bottom layer concrete;

[0029] Concrete is poured onto the bottom layer of concrete according to the spiral path to form the middle layer of concrete;

[0030] Concrete is poured onto the intermediate layer of concrete according to the spiral path to form the surface layer of concrete, thus completing the large-volume concrete pouring construction of the soft rock tunnel backfill area.

[0031] In one embodiment, the step of pouring concrete in layers and sequentially into multiple pouring units to complete the large-volume concrete pouring construction of the soft rock tunnel backfill area further includes:

[0032] Before pouring concrete on the bottom layer concrete according to the spiral path to form the middle layer concrete, the bottom layer concrete is isolated, protected and temperature-compensated to cure the bottom layer concrete.

[0033] Before pouring concrete onto the intermediate layer of concrete according to the spiral path to form the surface layer of concrete, the intermediate layer of concrete is ventilated and its humidity is regulated to cure it.

[0034] After pouring concrete onto the intermediate layer of concrete according to the spiral path to form the surface concrete, the surface concrete is covered and kept moist and its temperature is controlled to cure it.

[0035] In one embodiment, prior to the step of pouring concrete into multiple pouring units according to the spiral path to form the bottom layer concrete, the method for pouring large-volume concrete in the backfill area of ​​a soft rock tunnel further includes:

[0036] The surfaces of the soft rock interfaces corresponding to the multiple casting units are preheated.

[0037] In one embodiment, the steps of pouring concrete in layers and sequentially into multiple pouring units to complete the large-volume concrete pouring construction of the soft rock tunnel backfill area include:

[0038] The displacement, strain, and stress changes of the soft rock interfaces corresponding to multiple casting units are monitored to obtain monitoring results.

[0039] Concrete is poured in layers and sequentially into multiple pouring units, and the pouring situation is adjusted according to the monitoring results until the large-volume concrete pouring construction of the soft rock tunnel backfill area is completed.

[0040] The technical solution of this invention solves the technical problems of insufficient interfacial bonding strength and inability to adapt to the deformation characteristics of soft rock in traditional methods by forming a reinforced zone through stabilization treatment, targeted roughening treatment of the soft rock interface, and layered concrete pouring using a spiral path. It achieves gradient bonding between the soft rock and concrete interface, avoiding the risk of localized delamination; the spiral pouring path reduces the probability of cold joint formation, enabling large-volume concrete structures to maintain overall stability under soft rock deformation conditions; and the layered, intermittent pouring combined with curing measures effectively controls the generation of temperature cracks. This improves the interfacial bonding strength between the soft rock and concrete, enhancing the long-term stability of the tunnel structure. Attached Figure Description

[0041] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0042] Figure 1 This is a schematic flowchart of an embodiment of the method for pouring large-volume concrete in the backfill area of ​​a soft rock tunnel provided by the present invention.

[0043] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0044] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0045] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0046] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0047] Traditional concrete pouring techniques have several shortcomings in the construction of soft rock tunnels in backfill areas. First, the roughening treatment of the interface between soft rock and concrete is often neglected during construction, leading to insufficient bond strength and a tendency for interface delamination. Second, traditional large-volume concrete pouring often employs horizontal or sloping layering methods, which have significant limitations in the unique geological environment of soft rock tunnel backfill areas and cannot effectively adapt to the deformation characteristics of soft rock. More importantly, soft rock undergoes continuous creep deformation under the load of large-volume concrete, which significantly affects the stress distribution of the concrete and the overall structural stability. Existing construction methods often fail to fully consider the dynamic impact of soft rock deformation on the stress state of concrete, resulting in potential long-term structural stability issues after pouring. Furthermore, traditional methods lack specific measures to address the hardness differences at the soft rock interface, making it difficult to ensure the bonding quality between concrete and soft rock interfaces of varying hardness. Therefore, existing technologies urgently need improvement to address these problems.

[0048] To address this technical problem, this invention proposes a method for pouring large-volume concrete in the backfill area of ​​soft rock tunnels.

[0049] Please see Figure 1 In one embodiment of the present invention, the method for pouring large-volume concrete in the backfill area of ​​the soft rock tunnel includes:

[0050] Step S10: Stabilize the backfill area of ​​the soft rock tunnel to form a reinforced area;

[0051] Step S20: Roughen the soft rock interface in the reinforced area to form a surface to be poured.

[0052] Step S30: Divide the surface to be poured into multiple continuous pouring units according to the spiral path;

[0053] Step S40: Concrete is poured in layers and sequentially into multiple pouring units to complete the large-volume concrete pouring construction of the soft rock tunnel backfill area.

[0054] It should be noted that stabilization treatment refers to the process of improving the bearing capacity of soft rock through grouting or anchoring, specifically achieved through cement-water glass dual-liquid grouting, which fills rock fissures to form an integral reinforced structure. Roughening treatment refers to graded surface treatment based on the hardness differences of the soft rock; for example, mechanically roughening high-hardness areas and washing and leveling low-hardness areas to create a gradient rough interface and enhance bonding strength. A spiral path refers to a continuous curved trajectory extending outward from the geometric center; for example, using an Archimedean spiral to divide casting units, reducing the risk of cold joints during construction through path continuity. Layered casting refers to filling concrete layer by layer in a spiral sequence; for example, casting in three layers—bottom, middle, and top—forming an integral structure through layered superposition.

[0055] More specifically, the process begins by reinforcing the soft rock with grout to form a stable bearing layer, eliminating the risk of rock creep. Then, based on hardness test results, the reinforced area interfaces are treated differently: deep grooves are chiseled into high-hardness areas, medium-hardness areas are roughened after rinsing, and low-hardness areas are smoothed by removing slag. Next, the surface to be poured is divided into continuous units using a spiral pattern, with the bottom layer of concrete poured from the center outwards. After initial setting, the middle layer is poured along the same path, and finally, the surface layer is covered. In this process, the continuity of the spiral path ensures that the concrete load is evenly distributed to the soft rock, while curing measures can be implemented during the intervals between layered pours to control the heat of hydration.

[0056] Compared to existing technologies, traditional methods employ fixed-depth interface treatment, failing to consider the bond strength attenuation caused by differences in soft rock hardness. This proposed solution, however, uses a tiered treatment process to match the interface roughness with the rock mass strength. Existing horizontal layered casting methods often result in straight joints prone to stress concentration, while the curved characteristics of a spiral path allow for continuous changes in load transfer direction, effectively dispersing stress caused by soft rock deformation.

[0057] The technical solution provided by this invention solves the technical problems of insufficient interfacial bonding strength and inability to adapt to the deformation characteristics of soft rock in traditional methods by forming a reinforced zone through stabilization treatment, targeted roughening treatment of the soft rock interface, and layered concrete pouring using a spiral path. It achieves gradient bonding between the soft rock and concrete interface, avoiding the risk of localized delamination; the spiral pouring path reduces the probability of cold joint formation, enabling large-volume concrete structures to maintain overall stability under soft rock deformation conditions; and the layered, intermittent pouring combined with curing measures effectively controls the generation of temperature cracks. This improves the bonding strength between the soft rock and concrete interface and enhances the long-term stability of the tunnel structure.

[0058] In an embodiment of the present invention, the step of roughening the soft rock interface within the reinforced zone to form the surface to be poured includes:

[0059] Step S21: Perform a hardness test on the soft rock interface in the reinforced area to obtain the hardness distribution.

[0060] Step S22: Based on the hardness distribution, the soft rock interface is divided into multiple different treatment zones;

[0061] Step S23: Roughen the soft rock interface in multiple different processing areas to form the surface to be poured.

[0062] It should be noted that hardness testing refers to assessing the load-bearing capacity of soft rock by measuring its mechanical properties at different locations on the interface. Specifically, this can be achieved using equipment such as a rebound hammer or indenter for multi-point sampling to obtain hardness distribution data. Treatment area division refers to dividing the soft rock interface into sub-regions with different mechanical properties based on the hardness test results. This can be done by setting different hardness threshold ranges; for example, areas with hardness above a certain value can be classified as high-hardness areas, and those below a certain value as low-hardness areas. Roughening treatment refers to altering the surface morphology of the soft rock interface through physical or chemical means to enhance its bonding strength with concrete. This can be achieved through methods such as roughening, sandblasting, or high-pressure water jetting.

[0063] More specifically, during implementation, the reinforced soft rock interface is first subjected to multi-point hardness testing using a rebound hammer to generate a hardness distribution map. Based on the test results, the interface is divided into three treatment zones: high, medium, and low hardness. For example, areas with hardness values ​​above 50 MPa are designated as the first treatment zone, 30–50 MPa as the second treatment zone, and below 30 MPa as the third treatment zone. Subsequently, differentiated roughening processes are applied to different zones: high-hardness zones are deeply roughened to create a textured surface, medium-hardness zones are shallowly roughened combined with surface washing, and low-hardness zones are cleaned and leveled. This achieves a match between the interface treatment strength and the actual bearing capacity of the soft rock.

[0064] Compared to existing technologies, traditional methods typically apply a uniform surface treatment to the soft rock interface, neglecting the hardness differences between different areas. For example, excessive roughening in low-hardness areas can lead to rock fragmentation, while insufficient treatment in high-hardness areas fails to form an effective bonding surface. This solution, through hardness grading and differentiated treatment, avoids secondary damage to the soft rock structure while ensuring the effectiveness of interface treatment. It solves the problem of insufficient concrete bonding due to uneven hardness at the soft rock interface. By implementing zoned treatment, the integrity of the soft rock structure is maintained while ensuring interface roughness, reducing the risk of structural cracking caused by localized stress concentration after pouring, and improving the collaborative load-bearing capacity of the concrete and soft rock interface.

[0065] In an embodiment of the present invention, the step of dividing the soft rock interface into multiple different treatment zones according to the hardness distribution includes:

[0066] Step S221: Divide the region in the soft rock interface that meets the first hardness range value into the first sub-processing region;

[0067] Step S222: Divide the region in the soft rock interface that meets the second hardness range value into a second sub-processing region;

[0068] Step S223: Divide the region in the soft rock interface that meets the third hardness range value into the third sub-processing region;

[0069] Wherein, the first hardness range value is greater than the second hardness range value, and the second hardness range value is greater than the third hardness range value.

[0070] It should be noted that the first hardness range refers to the higher hardness interval determined by hardness testing, specifically using a Shore hardness tester, for example, a hardness value of 60–80 HS. This range is used to identify relatively stable areas in the soft rock interface, facilitating subsequent treatment with appropriate strength. The second hardness range refers to the medium hardness interval, for example, 40–60 HS. This range is used to identify areas with potential deformation risks, requiring medium-strength interface treatment measures. The third hardness range refers to the lower hardness interval, for example, 20–40 HS. This range is used to identify loosely structured or easily deformable areas, requiring surface leveling to reduce stress concentration risks.

[0071] More specifically, after completing the hardness test of the soft rock interface, the interface is divided into three stability levels—high, medium, and low—by dividing it into three hardness ranges. For example, the first sub-treatment area corresponds to the high-hardness rock layer in pressure-bearing parts such as the tunnel arch, the second sub-treatment area corresponds to the medium-hardness rock layer in the sidewall, and the third sub-treatment area corresponds to the loose rock layer at the bottom. Corresponding roughening, flushing, or leveling treatments are applied to different areas to ensure that the interface bonding strength matches the rock mass bearing capacity during concrete pouring. This division method avoids localized stress imbalances caused by uniform treatment and reduces structural damage caused by excessive roughening in weak areas.

[0072] This solution employs hardness grading to establish a gradient relationship between the depth and strength of interface treatment and the actual bearing capacity of the rock mass. For example, high-hardness areas are roughened with deep chiseling to enhance bonding strength, while low-hardness areas are leveled to avoid structural disturbance. This approach improves interface bonding strength while maintaining the stability of the soft rock itself. It solves the problem of uneven concrete bonding force distribution caused by hardness differences at the soft rock interface, ensuring that the interface treatment methods for different hardness areas are adapted to the mechanical properties of the rock mass. This effectively reduces the risk of cracks caused by localized bonding failure after concrete pouring, while also avoiding the non-uniform stress effects of soft rock deformation on the concrete structure, thus enhancing the collaborative bearing capacity of large-volume concrete and the soft rock interface.

[0073] In an embodiment of the present invention, the step of roughening the soft rock interface in multiple different processing areas to form the surface to be poured includes:

[0074] Step S231: The surface of the soft rock interface corresponding to the first sub-processing area is roughened to a first roughening depth.

[0075] Step S232: Rinse the surface of the soft rock interface corresponding to the second sub-processing area, and roughen the surface of the soft rock interface corresponding to the second sub-processing area to a second roughening depth.

[0076] Step S233: Clean and level the surface of the soft rock interface corresponding to the third sub-processing area to form the surface to be poured;

[0077] Wherein, the first chiseling depth is greater than the second chiseling depth.

[0078] It should be noted that the first roughening depth refers to the depth of mechanical scoring on the surface of high-hardness areas, which can be achieved using an impact drill or rock drill. This creates a textured surface that enhances the mechanical bonding between the concrete and the rock strata. The second roughening depth refers to the depth of shallow scoring on the surface of medium-hardness areas, which can be achieved using high-pressure water jets in conjunction with lightweight chisels. This creates an effective bonding surface while avoiding rock breakage. The third sub-treatment area cleaning and leveling refers to the removal of loose materials and contour shaping on the surface of low-hardness areas. This can be achieved using pneumatic cleaning tools in conjunction with a scraper, ensuring the smoothness of the pouring contact surface by eliminating surface defects.

[0079] More specifically, in the first sub-treatment area with higher hardness, a deep roughening process is used to increase the contact area and interlocking effect by creating deep grooves; in the second sub-treatment area with medium hardness, surface washing is performed first to remove loose dust, followed by shallow roughening to avoid damaging the rock mass structure; in the third sub-treatment area with low hardness, the focus is on surface cleaning, removing loose particles and smoothing uneven areas to create a uniform support surface. The intensity of the different treatment methods is adjusted according to the hardness gradient of the rock strata to ensure the interfacial bonding strength while avoiding over-treatment that could damage the rock mass.

[0080] This solution employs hardness grading to strengthen interfacial bonding in hard rock areas and reduce treatment intensity in soft rock areas to prevent structural damage, achieving a dynamic adaptation between interfacial treatment strength and rock mass bearing capacity. It effectively solves the problem of insufficient strength matching in the interfacial treatment of alternating hard and soft rock strata, enhancing the bond between concrete and rock while avoiding structural damage in weak areas, reducing stress concentration caused by improper interfacial treatment, and ensuring the overall stability of large-volume concrete structures.

[0081] In an embodiment of the present invention, the step of dividing the surface to be poured into multiple consecutive pouring units according to a spiral path includes:

[0082] Step S31: A spiral line extending outward from the geometric center of the surface to be poured is provided on the surface to be poured to form the spiral path.

[0083] It should be noted that the geometric center refers to the center point of symmetry of the planar shape of the surface to be poured. This can be achieved by measuring the boundary coordinates of the surface and calculating the geometric center, for example, using a total station or 3D laser scanning equipment. The spiral path refers to a continuously extending spiral trajectory outward from the geometric center. This can be achieved by using pre-set markers or dynamically adjusting the movement trajectory of the pouring equipment, for example, by controlling the movement path of the concrete pump truck to generate a spiral.

[0084] More specifically, after determining the geometric center of the surface to be poured, a spiral is drawn outward from this center according to a preset rotation direction and pitch. The spiral extends to cover the entire surface to be poured, thus dividing the surface into multiple continuous annular pouring units. The boundary of each pouring unit is defined by the trajectory of two adjacent spiral loops, and the pouring sequence proceeds layer by layer from the center outward along the spiral path. For example, the pitch of the spiral can be adjusted according to the hardness difference of the soft rock interface; the pitch can be appropriately increased in areas with higher hardness and decreased in areas with lower hardness.

[0085] Compared to existing technologies, traditional methods, which divide pouring units into horizontal or sloping layers, can easily lead to concentrated concrete loads on localized areas of soft rock, exacerbating the risk of interface deformation. In contrast, the spiral path division method allows the concrete load to be evenly distributed along the spiral direction, avoiding abrupt stress changes. Furthermore, the continuous nature of the spiral reduces the number of construction joints, lowering the probability of weak points forming at the interface.

[0086] This application achieves a gradual load transfer during concrete pouring, effectively mitigating the negative impact of soft rock deformation on concrete structures. The spiral path division method makes the bond strength distribution between concrete and soft rock more uniform, reducing the risk of cracks caused by local stress concentration, while improving the integrity and long-term stability of large-volume concrete structures.

[0087] In an embodiment of the present invention, the pitch of the helix located in the first sub-processing region is greater than the pitch of the helix located in the second sub-processing region, and the pitch of the helix located in the second sub-processing region is greater than the pitch of the helix located in the third sub-processing region.

[0088] It should be noted that the pitch of the helix refers to the axial distance between two adjacent helical turns. This can be achieved using laser layout combined with a mechanical positioning device. The density of concrete pouring units can be controlled by adjusting the pitch parameter. The first, second, and third sub-treatment areas refer to different treatment zones defined based on the hardness test results of the soft rock interface. This can be achieved through ground-penetrating radar scanning combined with hardness testing. Areas with higher hardness values ​​require denser pouring unit divisions.

[0089] More specifically, when setting the spiral path on the surface to be poured, the pitch parameters are adjusted according to the pre-divided soft rock interface treatment zones. For the first sub-treatment zone with higher hardness, a larger pitch is used to divide the pouring units, reducing concrete flow resistance; for the second sub-treatment zone with medium hardness, a medium pitch is used to balance structural strength and construction efficiency; for the third sub-treatment zone with low hardness, a smaller pitch is used to increase the density of pouring units to compensate for the bearing capacity of the soft rock. This gradient pitch setting method allows the concrete pouring path to match the mechanical properties of the soft rock.

[0090] This solution establishes a correlation between pitch and soft rock hardness, enabling the density of casting units to automatically adjust according to geological conditions. This effectively addresses the technical shortcomings of traditional methods, which are prone to stress concentration in alternating soft and hard strata. It achieves dynamic adaptation of casting path parameters to geological conditions, ensuring the bonding strength between soft rock and concrete while avoiding the risk of concrete cracking due to soft rock deformation. Through gradient pitch settings, the structural stress distribution is optimized while maintaining construction efficiency, effectively improving the construction quality of large-volume concrete casting under complex geological conditions.

[0091] In an embodiment of the present invention, the steps of pouring concrete in layers and sequentially into multiple pouring units to complete the large-volume concrete pouring construction of the soft rock tunnel backfill area include:

[0092] Step S41: Concrete is poured into multiple pouring units according to the spiral path to form the bottom layer concrete;

[0093] Step S42: Concrete is poured onto the bottom layer of concrete according to the spiral path to form the middle layer of concrete;

[0094] Step S43: Concrete is poured onto the intermediate layer of concrete according to the spiral path to form the surface layer of concrete, thus completing the large-volume concrete pouring construction of the soft rock tunnel backfill area.

[0095] It should be noted that a spiral path refers to a continuous curved trajectory extending outward from the geometric center, which can be achieved using a segmented spiral or a gradually varying pitch spiral. This path reduces the concentration of interfacial shear stress by controlling the direction of concrete flow. Layered pouring refers to constructing concrete in layers—bottom, middle, and top—in sequence, which can be achieved by stacking layers after each layer has solidified. This method reduces the risk of temperature cracking by releasing hydration heat in stages. The bottom layer of concrete is the first layer in direct contact with the soft rock interface, and can be achieved using materials with low hydration heat ratios. Its function is to initially fix the interface bonding state and provide a support foundation for subsequent pours. The middle layer of concrete is the transition layer between the bottom and top layers, and can be achieved using medium-flow concrete materials. This layer coordinates the deformation differences between the upper and lower layers by uniformly transferring the load. The top layer of concrete is the outermost sealing layer, and can be achieved using materials with high density ratios. Its function is to form a complete protective surface to prevent external environmental erosion.

[0096] More specifically, after dividing the surface to be poured into a spiral path, the bottom layer of concrete is first poured continuously along this path. After the bottom layer of concrete has solidified, a second pour is made in the middle layer area along the same spiral path, at which point the bottom layer has formed a stable support. Once the middle layer reaches the predetermined strength, the final layer of surface concrete is poured along the spiral path to seal it off. The pouring direction of each layer is consistent to avoid internal stress differences caused by path deviation. During the pouring process, the continuity of the spiral path ensures the uniformity of concrete flow, while the layered structure effectively disperses the stress transmission caused by soft rock deformation.

[0097] Compared to existing technologies, traditional horizontal layered casting is prone to interlayer slippage during soft rock deformation. The spiral path layered casting, through path continuity, enables each layer of concrete to form a circumferential stress compensation mechanism. In existing technologies, the temperature gradient created by a single casting leads to a decrease in interfacial bonding strength. The layered structure of this scheme allows each layer of concrete to independently complete its main hydration reaction, reducing the impact of overall temperature rise on the soft rock interface. This achieves a multi-layered, progressive bonding between the soft rock interface and the concrete, effectively suppressing interlayer delamination caused by continuous soft rock deformation. The spiral path layered casting makes the internal stress distribution of the concrete more consistent with the deformation characteristics of soft rock, avoiding the end stress concentration problem caused by traditional straight path casting. The stepped strength increase resulting from phased construction matches the overall structural stiffness with the soft rock deformation rate, significantly improving the long-term stability of large-volume concrete structures.

[0098] In an embodiment of the present invention, the step of pouring concrete in layers and sequentially into multiple pouring units to complete the large-volume concrete pouring construction of the soft rock tunnel backfill area further includes:

[0099] Step S401: Before pouring concrete on the bottom layer concrete according to the spiral path to form the middle layer concrete, the bottom layer concrete is isolated, protected and temperature compensated to cure the bottom layer concrete.

[0100] Step S402: Before pouring concrete onto the intermediate layer concrete according to the spiral path to form the surface concrete, the intermediate layer concrete is ventilated and its humidity is adjusted to cure it.

[0101] Step S403: After pouring concrete onto the intermediate layer concrete according to the spiral path to form the surface concrete, the surface concrete is covered and kept moist and its temperature is controlled to cure it.

[0102] It should be noted that isolation and protection refer to using physical barriers to isolate the concrete from external environmental interference. This can be achieved by laying waterproof cloth or plastic film to prevent moisture evaporation and contact with contaminants. Temperature compensation refers to actively regulating the concrete temperature to maintain suitable curing conditions. This can be achieved using electric blankets or circulating warm water systems to reduce cracks caused by temperature stress. Ventilation and humidity control refers to controlling the humidity of the concrete surface through airflow circulation. This can be achieved using axial flow fans or atomizing humidifiers to balance the moisture distribution during the hardening process. Covering and moisturizing refers to keeping the concrete surface moist through sealing materials. This can be achieved using wet burlap sacks or moisturizing films to slow down moisture loss. Temperature control refers to maintaining the concrete within a stable temperature range. This can be achieved using constant temperature curing sheds or temperature sensor-linked heating devices to avoid shrinkage and deformation caused by temperature differences.

[0103] More specifically, after the bottom layer of concrete is poured, a waterproof cloth is laid on the surface to isolate it from the external environment. Simultaneously, an electric heating blanket is used to evenly heat the concrete and maintain its temperature, allowing it to harden under constant conditions. Before pouring the middle layer of concrete, an axial flow fan is used to ventilate the bottom layer surface, and atomizing nozzles are used to regulate air humidity, ensuring that the interface between the middle layer and the bottom layer is in a suitable humidity environment. After the top layer of concrete is poured, it is covered with wet burlap sacks and a constant-temperature curing shed is erected. Temperature changes are continuously monitored and heating power is adjusted, allowing the surface concrete to harden slowly in a humid and constant-temperature environment. By implementing differentiated curing measures in stages, the hardening process of each layer of concrete is optimized, reducing the accumulation of internal stress caused by environmental fluctuations.

[0104] This application, through layered implementation of isolation protection, temperature compensation, ventilation regulation, and covering for moisture retention, can adapt to the complex environment of concrete curing in soft rock tunnel backfill areas, avoiding the decrease in interlayer bond strength caused by sudden temperature changes or humidity imbalances. It effectively solves the structural stability problem caused by the interaction between soft rock deformation and concrete hardening processes. The isolation protection and temperature compensation of the bottom layer concrete reduce early shrinkage cracks, the ventilation and humidity regulation of the middle layer concrete optimize the bonding performance of the interlayer interfaces, and the covering for moisture retention and temperature control of the surface layer concrete inhibits surface cracking. The synergistic effect of each layer of curing measures enhances the overall density and deformation resistance of the concrete structure.

[0105] In an embodiment of the present invention, prior to the step of pouring concrete into multiple pouring units according to the spiral path to form the bottom layer concrete, the method for pouring large-volume concrete in the backfill area of ​​a soft rock tunnel further includes:

[0106] Step S400: Preheat the surface of the soft rock interface corresponding to the plurality of casting units.

[0107] It should be noted that preheating treatment refers to the process of regulating the temperature of the soft rock interface through an external heat source. This can be achieved using electric blankets, steam injection, or a hot air circulation system. By increasing the interface temperature, the temperature difference between the concrete and the soft rock is reduced. This step aims to reduce the shrinkage stress caused by the temperature gradient during concrete setting, while simultaneously promoting the early bond strength development between the concrete and the soft rock interface.

[0108] More specifically, when preheating is performed, the corresponding preheating temperature is first determined based on the type of treatment zone defined by the soft rock interface. For example, a higher preheating temperature can be used for the first sub-treatment zone with higher hardness to enhance interfacial activity; a medium preheating temperature is used for the second sub-treatment zone with lower hardness to avoid damage to the soft rock structure; and a base preheating temperature is used for the third sub-treatment zone that needs to be leveled to maintain interface stability. During the preheating process, temperature sensors are deployed at different locations on the interface to monitor the temperature distribution in real time, and uniform temperature control is achieved by adjusting the heat source power.

[0109] In some specific implementations, the preheating treatment can adopt a staged heating method. In the initial stage, the temperature is increased to the target temperature at a rate not exceeding 10°C per hour. The heat preservation stage lasts for 2 to 4 hours to allow sufficient heat conduction. In the cooling stage, natural cooling is used to control the temperature difference between the interface and the concrete to be poured to within 15°C. After preheating, any residual condensate or impurities on the interface surface need to be cleaned a second time.

[0110] This solution effectively reduces interfacial stress concentration caused by sudden temperature changes through interface preheating treatment. Simultaneously, temperature regulation enhances the hydration reaction activity between the soft rock surface and concrete, preventing bond strength loss due to temperature differences. It solves the problem of decreased bond strength between the soft rock interface and concrete caused by temperature differences, reduces the generation of microcracks caused by temperature stress, and improves the integrity and durability of large-volume concrete structures. In particular, it enhances the shear resistance of the interfacial region under continuous deformation conditions in soft rock.

[0111] In an embodiment of the present invention, the steps of pouring concrete in layers and sequentially into multiple pouring units to complete the large-volume concrete pouring construction of the soft rock tunnel backfill area include:

[0112] Step S410: Monitor the displacement, strain, and stress changes of the soft rock interfaces corresponding to the multiple casting units, and obtain the monitoring results;

[0113] Step S420: Concrete is poured in layers and sequentially into multiple pouring units, and the pouring situation is adjusted according to the monitoring results until the large-volume concrete pouring construction of the soft rock tunnel backfill area is completed.

[0114] It should be noted that displacement refers to the spatial change of the soft rock interface during concrete pouring, which can be measured in real time using displacement sensors or laser rangefinders to determine the degree of local deformation of the soft rock. Strain refers to the degree of deformation of the soft rock interface under stress, which can be continuously monitored using strain gauges or fiber optic sensors to assess the mechanical response of the soft rock-concrete interface. Stress variation refers to the dynamic change in the load distribution on the soft rock interface, which can be collected at multiple points using pressure sensors or stress gauges to analyze the impact of concrete pouring on load transfer in the soft rock. Monitoring results refer to the comprehensive data set formed by collecting the above parameters, which can be analyzed in real time using a data acquisition system and algorithm model to guide the adjustment of concrete pouring processes. Adjusting the concrete pouring process refers to dynamically controlling the pouring speed, layer thickness, or pouring sequence based on monitoring data, which can be achieved by adjusting pumping equipment parameters or construction paths to balance the interaction between soft rock deformation and the concrete solidification process.

[0115] More specifically, during the layered pouring process, displacement sensors are placed at key locations on the soft rock interface to collect real-time rock displacement data; strain gauges are distributed along the interface to monitor local deformation trends; and pressure sensors are embedded in the contact layer between the soft rock and concrete to record stress distribution changes. The monitoring data is wirelessly transmitted to the control terminal, where it is processed by algorithms to generate pouring parameter adjustment commands. For example, when the displacement in a certain area exceeds a threshold, the pouring speed in that area is automatically reduced; when abnormal fluctuations occur in the stress change curve, pouring is immediately suspended and support reinforcement is initiated. Through this dynamic feedback mechanism, it is ensured that concrete pouring and soft rock deformation remain coordinated, avoiding interface cracking or structural instability caused by stress concentration.

[0116] Compared to existing technologies, traditional methods rely solely on experience to judge the pouring process, lacking quantitative monitoring of the dynamic response of soft rock. Existing technologies do not establish a real-time correlation between pouring parameters and rock mass mechanical behavior, making it impossible to promptly address the risks posed by continuous deformation of soft rock. This solution, through multi-parameter synchronous monitoring and intelligent control, improves the controllability of the construction process and effectively solves the problem of reduced bond strength caused by asynchronous soft rock deformation and concrete solidification.

[0117] Through the above technical solution, this application can capture the changes in the mechanical state of the soft rock-concrete interface in real time, accurately control the load transfer path during the pouring process, and avoid abnormal stress distribution in concrete caused by soft rock creep. Through a data-driven dynamic adjustment mechanism, the collaborative bearing capacity of large-volume concrete and soft rock tunnels is significantly improved, ensuring the overall stability of the structure during long-term use and solving the technical defects of insufficient interface bonding strength and accumulation of structural hazards in traditional construction methods.

[0118] Based on the above embodiments, a specific implementation method is shown here for ease of understanding:

[0119] The technical solution of this invention includes three main stages:

[0120] The first stage is the soft rock foundation pretreatment stage, which mainly completes the stabilization treatment of the soft rock surface and the preparation work for pouring the foundation; the second stage is the layered progressive pouring stage, which adopts innovative pouring technology to achieve orderly construction of large volume concrete; the third stage is the dynamic curing and stress control stage, which ensures concrete quality and structural stability through special curing methods.

[0121] Phase 1: Soft Rock Foundation Pretreatment Phase

[0122] Steps for stabilizing soft rock surfaces:

[0123] Before pouring large-volume concrete in the backfill area of ​​a soft rock tunnel, the soft rock surface must first be stabilized. Due to its inherent low strength and easy weathering characteristics, soft rock is prone to local deformation or failure when subjected to large-volume concrete loads. Therefore, special treatment methods must be used to improve its load-bearing capacity and stability.

[0124] In practice, a detailed geological survey of the soft rock surface is first conducted to identify the degree of weathering, fissure development, and bearing capacity distribution. Then, a zoned treatment approach is adopted, employing appropriate stabilization measures for different areas of the soft rock. For areas with mild weathering, surface cleaning and light reinforcement are used; for areas with severe weathering, in-depth treatment is required, including removing loose rock masses, filling fissures, and strengthening support.

[0125] In the process of stabilizing soft rock surfaces, special attention is paid to the treatment of structural planes. Structural planes in soft rock include bedding planes, joint planes, and fault planes, which are often weak points in the stability of soft rock. For bedding planes, it is necessary to assess the impact of their dip and angle on concrete pouring. When the dip angle of the bedding plane is large, a stepped excavation method is needed to increase the contact area and friction. For joint planes, it is necessary to remove the filling material in the joints and determine whether filling reinforcement is needed based on the joint's opening and connectivity. For fault planes, due to their often high mobility, special reinforcement measures are required, such as installing anchor bolts or grouting reinforcement.

[0126] Interface roughening preprocessing technique:

[0127] Progressive interface roughening technique:

[0128] Traditional concrete pouring often neglects the roughening treatment of the interface between soft rock and concrete, resulting in insufficient bonding strength between the two. This invention innovatively proposes a progressive interface roughening treatment technology, which employs different degrees of roughening treatment methods based on the hardness distribution and structural characteristics of soft rock to form a gradient of interface roughness.

[0129] In practice, the surface hardness of the soft rock is first tested, and a hardness distribution map is drawn. Then, based on the hardness distribution, the soft rock surface is divided into different treatment zones. For areas with higher hardness, mechanical roughening is used to increase surface roughness, with the roughening depth controlled at 5–10 mm and the roughening spacing at 20–30 mm. For areas with medium hardness, high-pressure water washing combined with light roughening is used to remove loose material from the surface while moderately increasing surface roughness. For areas with lower hardness, cleaning and leveling methods are mainly used to avoid over-treatment that could further loosen the soft rock.

[0130] The key to progressive interface roughening lies in creating a continuously varying roughness gradient, which makes the stress transfer between concrete and soft rock more uniform. At the interface between different roughness regions, a transitional treatment method is used to avoid stress concentration caused by abrupt changes in roughness. Simultaneously, during the roughening process, care must be taken to protect the overall structure of the soft rock to avoid affecting overall stability due to improper local treatment.

[0131] Phase Two: Layered Gradual Pouring Phase

[0132] Spiral layered progressive casting technology:

[0133] Traditional methods for pouring large volumes of concrete often employ horizontal or sloping layering, but these methods have significant limitations in the unique environment of soft rock tunnel backfill areas. This invention innovatively proposes a spiral layered progressive pouring technology, which combines the characteristics of soft rock geology with the spatial constraints of the tunnel backfill area, achieving orderly concrete pouring through a spiral pouring path.

[0134] The core idea of ​​spiral layered progressive pouring technology is to divide the entire backfill area into multiple pouring units according to a spiral path. The volume of each pouring unit is controlled within a reasonable range, which ensures both the continuity of pouring and effective control of the temperature stress of the concrete. In practice, the spiral pouring path is first designed based on the geometry of the backfill area and the soft rock geological conditions. The starting point of the spiral path is usually set at the center of the backfill area, and then it expands outward according to a predetermined pitch and helix angle.

[0135] During the spiral pouring process, the thickness of each layer is controlled between 0.3 and 0.5 meters. This ensures both the density of the concrete and effective control of temperature changes during pouring. The time interval between pouring adjacent layers is adjusted according to the initial setting time of the concrete and the ambient temperature, generally controlled between 2 and 4 hours. This time interval control ensures that the lower layer of concrete has sufficient load-bearing capacity and that the interlayer bonding is effective.

[0136] The design of the spiral pouring path also takes into account the heterogeneity of soft rock geology. In areas where the soft rock strength is low, the spiral pitch is appropriately reduced and the number of pouring layers is increased to reduce the pressure of a single layer of concrete on the soft rock; in areas where the soft rock strength is high, the spiral pitch can be appropriately increased to improve pouring efficiency. At the same time, special pouring techniques are used at the turning points and intersections of the spiral path to ensure the continuity and integrity of the concrete.

[0137] Temperature stress control technology:

[0138] Temperature stress control during the pouring of large-volume concrete is a key factor in ensuring project quality. In the backfill area of ​​soft rock tunnels, the poor thermal conductivity of soft rock restricts the dissipation of heat from concrete hydration, which can easily lead to excessively high internal temperatures and generate harmful temperature stresses.

[0139] This invention employs a phased temperature control strategy, dividing the entire pouring process into three stages: a heating phase, a constant temperature phase, and a cooling phase. Different temperature control measures are used in each stage. During the heating phase, the main focus is on controlling the concrete pouring temperature and the rate of hydration heat generation, achieved by adjusting the concrete mix proportions and pouring speed. During the constant temperature phase, insulation measures are used to maintain a stable internal temperature in the concrete, preventing excessive temperature gradients. During the cooling phase, the main focus is on controlling the cooling rate to avoid tensile stress caused by excessively rapid cooling.

[0140] In practice, before pouring concrete, the soft rock surface is preheated to match its temperature with the concrete pouring temperature, reducing the temperature difference at the interface. During pouring, the concrete outlet temperature and pouring speed are controlled to keep the rate of temperature rise within the concrete within a reasonable range. After the concrete is poured, a layered insulation method is used, employing different insulation measures for different depths of concrete.

[0141] Phase Three: Dynamic Curing and Stress Control Phase

[0142] Dynamic stress monitoring and control technology:

[0143] Dynamic stress control technology based on soft rock deformation:

[0144] Soft rock undergoes continuous deformation when subjected to large-volume concrete loads, which affects the stress distribution and structural stability of the concrete. Traditional construction methods often overlook the impact of soft rock deformation on the stress state of concrete, leading to potential long-term structural instability issues. This invention innovatively proposes a dynamic stress control technology based on soft rock deformation, which dynamically adjusts the stress state of concrete by monitoring the deformation of the soft rock in real time.

[0145] The implementation of this technology involves two aspects: the establishment of a deformation monitoring system and the implementation of stress control measures. The deformation monitoring system monitors the displacement, strain, and stress changes of the soft rock in real time by setting monitoring points on the surface and inside the rock. The layout of the monitoring points is optimized based on the geological conditions of the soft rock and the load distribution of the concrete to ensure a comprehensive reflection of the deformation state of the soft rock.

[0146] Regarding stress control, corresponding control measures are adopted based on the changing trends of monitoring data. When monitoring data shows that the deformation rate of soft rock is too fast, the deformation is slowed down by adjusting the concrete pouring speed or adding temporary supports; when monitoring data shows stress concentration in certain areas, stress concentration is alleviated by local unloading or stress redistribution.

[0147] The key to dynamic stress control lies in establishing the correlation between soft rock deformation and concrete stress. By using a large amount of field monitoring data and theoretical analysis, a corresponding mathematical model can be established, which can predict the stress change trend of concrete based on real-time data of soft rock deformation, thereby enabling corresponding control measures to be taken in advance.

[0148] Layered maintenance technology:

[0149] The quality of concrete curing directly affects its final strength and durability. In the special environment of soft rock tunnel backfill areas, traditional curing methods often fail to achieve ideal results. This invention employs layered curing technology, using corresponding curing measures based on the characteristics of different layers of concrete and environmental conditions.

[0150] Layered curing technology divides the entire concrete structure into three curing zones according to depth: surface, intermediate, and bottom. The surface concrete, being directly exposed to air, is susceptible to changes in ambient temperature and humidity, and is cured using methods such as covering for moisture retention and temperature control. The intermediate concrete curing primarily considers the dissipation of internal hydration heat and humidity maintenance, employing methods such as moderate ventilation and humidity regulation. The bottom concrete, being in direct contact with soft rock, requires consideration of the soft rock's water absorption and thermal conductivity, necessitating methods such as isolation protection and temperature compensation.

[0151] During the curing process, special attention is paid to the curing quality of the interlayer interfaces. Because a layered casting method is used, the bonding quality of the interlayer interfaces has a significant impact on the overall structural performance. Specific curing measures are implemented at the interlayer interfaces, such as increasing humidity and controlling temperature gradients, to ensure the effectiveness of the interlayer bonding.

[0152] The method for pouring large-volume concrete in the backfill area of ​​soft rock tunnels of the present invention effectively improves the interfacial bonding strength between soft rock and concrete through progressive interface roughening treatment technology, thereby increasing the interfacial shear strength by more than 30%; the spiral layered progressive pouring technology effectively controls the temperature stress of concrete, thereby reducing the maximum temperature stress by more than 25%; and the dynamic stress control technology based on soft rock deformation significantly improves the long-term stability of the structure, keeping the soft rock deformation within the allowable range.

[0153] The entire construction method exhibits excellent adaptability and operability, enabling flexible application under diverse soft rock geological conditions and ensuring the quality and safety of large-volume concrete pouring. The implementation of this invention effectively reduces construction risks, enhances the economic and social benefits of the project, and provides reliable technical support for the construction of soft rock tunnels.

[0154] The above description is merely an exemplary embodiment of the present invention and does not limit the scope of protection of the present invention. Any equivalent structural transformations made based on the technical concept of the present invention and the contents of the specification and drawings of the present invention, or direct / indirect applications in other related technical fields, are included within the scope of protection of the present invention.

Claims

1. A method for pouring large-volume concrete in the backfill area of ​​a soft rock tunnel, characterized in that, include: The soft rock tunnel backfill area is stabilized to form a reinforced zone; The soft rock interface in the reinforcement zone is roughened to form a surface to be poured; the hardness of the soft rock interface in the reinforcement zone is tested to obtain the hardness distribution; based on the hardness distribution, the soft rock interface is divided into multiple different treatment areas. The region in the soft rock interface that meets the first hardness range value is divided into the first sub-processing region; The region in the soft rock interface that meets the second hardness range value is divided into the second sub-processing region; The soft rock interface is divided into a third sub-processing area, where the first hardness range value is greater than the second hardness range value, and the second hardness range value is greater than the third hardness range value. The soft rock interfaces within multiple different processing areas are roughened to form the surface to be poured. The surface of the soft rock interface corresponding to the first sub-processing area is roughened to a first roughening depth. The surface of the soft rock interface corresponding to the second sub-processing area is washed and roughened to a second roughening depth. The surface of the soft rock interface corresponding to the third sub-processing area is cleaned and leveled to form the surface to be poured. The first roughening depth is greater than the second roughening depth. The surface to be poured is divided into multiple continuous pouring units according to the spiral path; the pitch of the spiral line in the first sub-processing area is greater than the pitch of the spiral line in the second sub-processing area, and the pitch of the spiral line in the second sub-processing area is greater than the pitch of the spiral line in the third sub-processing area. Concrete is poured in layers and sequentially into multiple pouring units to complete the large-volume concrete pouring construction of the soft rock tunnel backfill area; the displacement, strain, and stress changes of the soft rock interfaces corresponding to the multiple pouring units are monitored to obtain monitoring results; concrete is poured in layers and sequentially into multiple pouring units, and the concrete pouring situation is adjusted according to the monitoring results until the large-volume concrete pouring construction of the soft rock tunnel backfill area is completed.

2. The method for pouring large-volume concrete in the backfill area of ​​a soft rock tunnel as described in claim 1, characterized in that, The steps of dividing the surface to be poured into multiple consecutive pouring units according to a spiral path include: A spiral path is formed by extending outward from the geometric center of the surface to be poured.

3. The method for pouring large-volume concrete in the backfill area of ​​a soft rock tunnel as described in claim 1 or 2, characterized in that, The steps for completing the large-volume concrete pouring construction of the soft rock tunnel backfill area include: pouring concrete in layers and sequentially into multiple pouring units. Concrete is poured into multiple pouring units according to the spiral path to form the bottom layer concrete; Concrete is poured onto the bottom layer of concrete according to the spiral path to form the middle layer of concrete; Concrete is poured onto the intermediate layer of concrete according to the spiral path to form the surface layer of concrete, thus completing the large-volume concrete pouring construction of the soft rock tunnel backfill area.

4. The method for pouring large-volume concrete in the backfill area of ​​a soft rock tunnel as described in claim 3, characterized in that, The steps of pouring concrete in layers and sequentially into multiple pouring units to complete the large-volume concrete pouring construction of the soft rock tunnel backfill area also include: Before pouring concrete on the bottom layer concrete according to the spiral path to form the middle layer concrete, the bottom layer concrete is isolated, protected and temperature-compensated to cure the bottom layer concrete. Before pouring concrete onto the intermediate layer of concrete according to the spiral path to form the surface layer of concrete, the intermediate layer of concrete is ventilated and its humidity is regulated to cure it. After pouring concrete onto the intermediate layer of concrete according to the spiral path to form the surface concrete, the surface concrete is covered and kept moist and its temperature is controlled to cure it.

5. The method for pouring large-volume concrete in the backfill area of ​​a soft rock tunnel as described in claim 3, characterized in that, Before the step of pouring concrete into multiple pouring units according to the spiral path to form the bottom layer concrete, the method for pouring large-volume concrete in the backfill area of ​​a soft rock tunnel further includes: The surfaces of the soft rock interfaces corresponding to the multiple casting units are preheated.

Images