Soft rock tunnel 3D printing backfill body construction method

Abstract

The application discloses a kind of soft rock tunnel 3D printing backfill construction methods, it is related to tunnel construction technical field, the target backfill volume of the overbreak area of soft rock tunnel is collected, and the first current real-time deformation data of overbreak area, according to the first current real-time deformation data, obtain the target deformation duration of target geologic body deformation in overbreak area to fill up overbreak area, when target deformation duration is greater than preset duration, then according to the backfill scheme of the first current real-time deformation data of overbreak area, using 3D printing equipment according to backfill scheme in overbreak area first backfill body is made, when first backfill body reaches preset strength, using 3D printing equipment continues in overbreak area second backfill body is made, to complete the backfill operation of overbreak area, so that the first backfill body formed by making can resist the deformation effect of target geologic body, can avoid the defect that backfill body is damaged due to the deformation phenomenon of target geologic body, improve the safety of tunnel use.

Description

Technical Field

[0001] This invention relates to the field of soft rock tunnel construction technology, and in particular to a method for constructing 3D-printed backfill in soft rock tunnels. Background Technology

[0002] During the construction of soft rock tunnels, over-excavation occurs due to the inherent soft rock properties, necessitating backfilling of the over-excavated areas. Current technology typically uses concrete pouring for backfilling. While this method effectively addresses the over-excavation in soft rock tunnels, the inherent deformation of the tunnel itself causes subsequent deformation of the backfill area. This poses a risk of deformation and damage to the backfill material, compromising the safe operation of the tunnel. Summary of the Invention

[0003] The main objective of this invention is to propose a 3D-printed backfill construction method for soft rock tunnels. This method aims to address the technical problem that while existing backfilling methods can achieve backfilling of over-excavated areas in soft rock tunnels, the deformation of the soft rock tunnel itself causes deformation of the backfill area after backfilling. This results in the risk of deformation and damage to the backfill material, affecting the safe use of the tunnel.

[0004] To achieve the above objectives, in a first aspect, the present invention proposes a method for constructing 3D-printed backfill material for soft rock tunnels, comprising the following steps:

[0005] The target backfill volume of the over-excavated area of ​​the soft rock tunnel and the first current real-time deformation data of the over-excavated area are collected; wherein, the first current real-time deformation data includes the average deformation rate;

[0006] Based on the first current real-time deformation data, the target deformation time from deformation of the target geological body in the over-excavation area to filling the over-excavation area is obtained;

[0007] When the target deformation duration exceeds a preset duration, a backfilling scheme for the over-excavated area is determined based on the first current real-time deformation data; wherein, the backfilling scheme includes the bending angle, bending arc, bending direction, cross-sectional area, and cross-sectional shape of the first backfill body required to resist the first current real-time deformation data;

[0008] The first backfill body was constructed in the over-excavated area using 3D printing equipment according to the backfilling plan.

[0009] Once the first backfill material reaches the preset strength, the 3D printing equipment is used to continue applying a second backfill material to the over-excavated area to complete the backfilling operation of the over-excavated area.

[0010] In one embodiment, the step of using a 3D printing device to construct the first backfill body in the over-excavated area according to the backfilling plan includes:

[0011] In the over-excavated area, the first backfill body is constructed using a 3D printing device and the first backfill material in accordance with the backfilling plan.

[0012] In one embodiment, the first backfill material is steel fiber reinforced concrete or quartz sand fiber reinforced concrete.

[0013] In one embodiment, the step of continuing to use the 3D printing equipment to apply a second backfill material to the over-excavated area after the first backfill material reaches a preset strength, in order to complete the backfilling operation of the over-excavated area, includes:

[0014] Once the first backfill material reaches the preset strength, the 3D printing equipment is used to apply the second backfill material to the over-excavated area to complete the backfilling operation of the over-excavated area.

[0015] In one embodiment, the second backfill material is a building foam material.

[0016] In one embodiment, the building foam material includes any one of foamed concrete, expanded perlite, or polyurethane foam.

[0017] In one embodiment, the step of collecting the target backfill volume of the over-excavated area of ​​the soft rock tunnel and the first current real-time deformation data of the over-excavated area includes:

[0018] Scan the over-excavated area of ​​the soft rock tunnel to obtain the target backfill volume of the over-excavated area;

[0019] Photographic and video recording operations are performed on the over-excavated area to collect and obtain the first current real-time deformation data of the over-excavated area.

[0020] In one embodiment, the step of performing photographic and video recording operations on the over-excavated area to collect and obtain the first current real-time deformation data of the over-excavated area includes:

[0021] The over-excavated area is photographed and videotaped using a preset camera device to collect and obtain the first current real-time deformation data of the over-excavated area.

[0022] In one embodiment, the step of using a preset camera device to perform photographic and video recording operations on the over-excavated area to collect and obtain the first current real-time deformation data of the over-excavated area includes:

[0023] The over-excavated area is photographed and videotaped using a preset camera device according to a preset shooting parameter set, so as to collect and obtain the first current real-time deformation data of the over-excavated area; wherein, the preset shooting parameter set includes a preset shooting path and preset shooting parameters.

[0024] In one embodiment, the step of using a preset camera device to perform photographic and video recording operations on the over-excavated area according to a preset shooting parameter set, so as to collect and obtain the first current real-time deformation data of the over-excavated area, includes:

[0025] Using a preset camera device and according to a preset shooting parameter set, the over-excavated area is photographed and videotaped to obtain an image sequence of the over-excavated area;

[0026] Based on the image sequence, obtain the target image set of the over-dug area;

[0027] Based on the target image set, a three-dimensional digital reference model of the soft rock tunnel is established; wherein, the three-dimensional digital reference model includes a joint orientation model of the geological body of the soft rock tunnel;

[0028] The soft rock tunnel is continuously photographed and videotaped to obtain the current image set corresponding to each acquisition time; wherein, each current image in the current image set records the current joint orientation of the geological body;

[0029] The current image set is imported into the three-dimensional digital benchmark model, and the current joint orientation is compared and analyzed with the joint orientation model to obtain the first current real-time deformation data of the over-excavated area.

[0030] When using the technical solution of this invention, the target backfill volume of the over-excavated area of ​​the soft rock tunnel and the first current real-time deformation data of the over-excavated area are first collected. Then, based on the first current real-time deformation data, the target deformation time for the target geological body in the over-excavated area to deform and fill the over-excavated area is obtained. When the target deformation time is longer than a preset time, the backfilling scheme for the over-excavated area is determined based on the first current real-time deformation data. The first backfill body is then constructed in the over-excavated area using 3D printing equipment according to the backfilling scheme. After the first backfill body reaches a preset strength, the second backfill body is constructed in the over-excavated area using 3D printing equipment to complete the backfilling operation of the over-excavated area. This invention, by first determining the time for the target geological body in the over-excavated area to deform and fill the over-excavated area, and only constructing the first backfill body in the over-excavated area according to the designed backfilling scheme when the time is longer than the preset time, ensures that the constructed first backfill body can resist the deformation of the target geological body. Ultimately, this invention avoids the defect of backfill body damage caused by the deformation of the target geological body, thus improving the safety of tunnel use. Attached Figure Description

[0031] 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.

[0032] Figure 1 A schematic diagram of the construction method for 3D printing backfill in soft rock tunnels provided by the present invention;

[0033] Figure 2 This is a flowchart illustrating step S100 of the present invention.

[0034] Figure 3 for Figure 2 The flowchart of step S121a in the example is shown.

[0035] 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

[0036] 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.

[0037] 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.

[0038] 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.

[0039] The applicant's research found that during the construction of soft rock tunnels, over-excavation occurs due to the inherent soft rock properties, necessitating backfilling of the over-excavated areas. Current technology typically uses concrete pouring for backfilling. While this method can effectively backfill over-excavated areas in soft rock tunnels, the inherent deformation of the tunnel itself causes deformation of the backfill area after backfilling. This poses a risk of deformation and damage to the backfill material, impacting the safe operation of the tunnel.

[0040] To address the aforementioned issues, the applicant proposes a 3D-printed backfill construction method for soft rock tunnels. The technical concept of this method is as follows: First, the target backfill volume of the over-excavated area is collected, along with real-time deformation data of the geological body in the over-excavated area. Based on the collected deformation data, the deformation time required for the geological body in the over-excavated area to deform and fill the over-excavated area is determined. When the deformation time exceeds a preset duration, a backfill scheme for the over-excavated area is determined based on the real-time deformation data (wherein, the backfill scheme includes the bending angle, bending arc, bending direction, cross-sectional area, and cross-sectional shape of the backfill body required to resist the real-time deformation data). After determining the backfill scheme, a first backfill body (preferably high-ductility concrete) is constructed in the over-excavated area using 3D printing equipment. Once the first backfill body reaches a preset strength, a second backfill body is constructed in the same area using the same 3D printing equipment, thus completing the backfilling operation for the entire over-excavated area.

[0041] This invention proposes a method for constructing 3D-printed backfill material for soft rock tunnels.

[0042] Please see Figures 1 to 3 To facilitate understanding, this method for constructing 3D-printed backfill in soft rock tunnels includes the following steps:

[0043] S100. Collect the target backfill volume of the over-excavated area of ​​the soft rock tunnel and the first current real-time deformation data of the over-excavated area; wherein, the first current real-time deformation data includes the average deformation rate.

[0044] Specifically, the target backfill volume refers to the geometric space volume that needs to be filled in the over-excavated area. This volume can be obtained using 3D laser scanning technology to determine the amount of material needed. The first real-time deformation data includes the displacement rate and direction parameters of the surrounding rock, which can be collected by fiber optic sensors installed on the tunnel wall to predict deformation trends.

[0045] S200. Based on the first current real-time deformation data, obtain the target deformation time from deformation of the target geological body in the over-excavation area to filling the over-excavation area.

[0046] Specifically, the bending angle in the backfill scheme refers to the angle between the printing path and the main deformation direction, which can be set to a range of 30° to 60° to disperse the stress transfer path.

[0047] S300. When the target deformation duration exceeds a preset duration, a backfilling scheme for the over-excavated area is determined based on the first current real-time deformation data. The backfilling scheme includes the bending angle, bending arc, bending direction, cross-sectional area, and cross-sectional shape of the first backfill body required to resist the first current real-time deformation data.

[0048] Specifically, the bending radius refers to the radius of curvature between printed layers, which can be controlled within the range of 0.5 meters to 1.5 meters to enhance the structural bending resistance. The cross-sectional area refers to the cross-sectional dimension of a single layer of printed material, which can be designed as a trapezoid or wavy shape to improve the structural load-bearing efficiency.

[0049] S400. In the over-excavated area, use a 3D printing device to construct the first backfill body according to the backfilling plan;

[0050] S500. After the first backfill material reaches the preset strength, the 3D printing equipment is used to continue to apply the second backfill material in the over-excavated area to complete the backfilling operation of the over-excavated area.

[0051] After acquiring deformation rate data through a real-time monitoring system, a time-series-based deformation prediction model is established. When the predicted deformation duration exceeds a safety threshold, a combination of backfill parameters with a specific spatial morphology is calculated and generated. The 3D printing equipment applies an initial support layer according to preset path parameters, forming a corrugated structure at a specific angle to the deformation direction. After the initial support layer solidifies, a lightweight filling layer with buffering function is superimposed, forming a rigid-flexible composite structural system. This process, through the dynamic coupling of deformation data and printing parameters, ensures that each layer of the backfill structure collaboratively resists deformation stress at different stages.

[0052] In this embodiment, the present invention constructs a composite structure in stages. The initial corrugated support layer effectively absorbs deformation energy, while the later lightweight filling layer provides space for deformation compensation. Existing technologies use fixed templates for construction, resulting in a single structural form. In contrast, this method uses 3D printing to achieve a spatial curved surface structure, ensuring that the cross-sectional shape of the backfill matches the stress distribution. Conventional construction relies on manual experience and judgment, while this method dynamically adjusts construction parameters based on real-time monitoring data, forming a data-driven intelligent construction process.

[0053] This application effectively solves the problem of cracking and damage to backfill in soft rock tunnels caused by continuous geological deformation. The corrugated structure design of the initial support layer disperses the stress concentration, while the lightweight filling layer provides buffer space for subsequent deformation. The composite structural system significantly improves the deformation adaptability of the backfill. Through dynamic matching of real-time data and printing parameters, the precise fit between the spatial shape of the backfill and the deformation trend of the surrounding rock is ensured, avoiding the technical defects of traditional rigid structures that are prone to damage.

[0054] In this embodiment, the target backfill volume of the over-excavated area of ​​the soft rock tunnel and the first current real-time deformation data of the over-excavated area are first collected. Then, based on the first current real-time deformation data, the target deformation time for the target geological body in the over-excavated area to deform and fill the over-excavated area is obtained. When the target deformation time is longer than a preset time, the backfilling scheme for the over-excavated area is determined based on the first current real-time deformation data. The first backfill body is constructed in the over-excavated area using 3D printing equipment according to the backfilling scheme. After the first backfill body reaches the preset strength, the second backfill body is constructed in the over-excavated area using 3D printing equipment to complete the backfilling operation of the over-excavated area. This invention, by first determining the time for the target geological body in the over-excavated area to deform and fill the over-excavated area, and only constructing the first backfill body in the over-excavated area according to the designed backfilling scheme when the time is longer than the preset time, ensures that the constructed first backfill body can resist the deformation of the target geological body. Ultimately, this invention avoids the defect of backfill body damage caused by the deformation of the target geological body, thus improving the safety of tunnel use.

[0055] In one embodiment, step S400 includes:

[0056] In the over-excavated area, the first backfill body is constructed using a 3D printing device and the first backfill material in accordance with the backfilling plan.

[0057] Specifically, the first backfill material refers to a composite material with tensile strength and crack resistance, which can be steel fiber reinforced concrete or quartz sand fiber reinforced concrete. Through the three-dimensional disordered distribution of fibers in the concrete matrix, a stress transmission path is formed that matches the deformation characteristics of the over-excavated area. Thus, when subjected to the shear force generated by the deformation of the geological body, the fiber bridging effect can inhibit crack propagation.

[0058] During the 3D printing process, the first backfill material is deposited layer by layer through the printing nozzle to form a structure with a preset bending angle and curvature. Fibers are oriented along the printing path during extrusion, forming a continuous fiber-reinforced network at the bending points. The fiber-reinforced network forms an angle with the deformation direction of the geological body, allowing the backfill to disperse concentrated stress throughout the structure through the synergistic effect of the fibers and the matrix when subjected to continuous deformation of soft rock. By controlling the printing layer thickness and fiber content, the bending strength of the material is dynamically matched to the average deformation rate of the over-excavated area, thus providing a stable support interface for the subsequent construction of the second backfill while completing the initial support.

[0059] In this embodiment, by combining fiber-reinforced materials with 3D printing technology, a reinforcing phase orthogonal to the deformation direction is formed inside the backfill, enabling the structure to maintain its integrity even under multi-directional deformation. Furthermore, in existing technologies, material properties and construction processes are separated, while this solution achieves synergistic optimization of material mechanical properties and structural geometric features by simultaneously controlling material proportions and printing parameters.

[0060] The application of fiber-reinforced materials allows the backfill to delay crack propagation through fiber bridging when subjected to shear deformation, while the directional fiber arrangement formed by 3D printing further enhances the bending resistance of key areas. This dual optimization of materials and processes enables the backfill to form effective support in the early stages of soft rock deformation, avoiding the risk of overall failure caused by local stress concentration in traditional homogeneous materials, and ensuring the safe implementation of subsequent construction procedures.

[0061] In one embodiment, the first backfill material is steel fiber reinforced concrete or quartz sand fiber reinforced concrete.

[0062] Specifically, steel fiber reinforced concrete refers to a composite material formed by incorporating short steel fibers into a concrete matrix. Copper-plated steel fibers with a diameter of 0.1-0.5 mm and a length of 10-30 mm can be used, which are uniformly dispersed in the concrete using mixing equipment to form a three-dimensional mesh support structure to enhance tensile strength. Quartz sand fiber reinforced concrete refers to inorganic fiber-reinforced concrete made by melting and drawing quartz sand into fibers. Quartz sand fibers with a length of 6-12 mm and a diameter of 5-15 micrometers can be used, which are mixed with concrete through a spraying process, utilizing the surface roughness of the fibers to improve interfacial adhesion.

[0063] Steel fibers form a continuous skeleton within concrete through the high tensile strength of the metallic material. In the early stages of soft rock deformation, the synergistic effect between the fiber and the matrix absorbs deformation energy and inhibits crack formation. Quartz sand fibers maintain long-term stability through the corrosion resistance of inorganic materials, and maintain the interfacial bonding between the fiber and concrete in humid geological environments. Both materials, through the mechanism of fiber stress dispersion and crack propagation blocking, enable the first backfill to maintain structural integrity under the pressure deformation of soft rock, avoiding brittle fracture caused by localized stress concentration.

[0064] The addition of steel fibers or silica sand fibers transforms concrete from a single brittle material into a tough composite material, significantly improving its crack resistance. Fiber-reinforced concrete can adapt to the dynamic deformation of soft rock without the need for additional reinforcement structures, solving the technical defect of incompatibility between backfill and surrounding rock deformation in traditional processes.

[0065] This application effectively solves the problem of backfill cracking caused by soft rock deformation. The fiber reinforcement allows the backfill to disperse stress through the internal fiber network when subjected to the compression of the surrounding rock, inhibiting crack propagation and ensuring that the first-stage backfill maintains structural stability before reaching the preset strength, thus providing a reliable support foundation for the subsequent construction of the second backfill.

[0066] In one embodiment, step S500 includes:

[0067] Once the first backfill material reaches the preset strength, the 3D printing equipment is used to apply the second backfill material to the over-excavated area to complete the backfilling operation of the over-excavated area.

[0068] Specifically, the second backfill material refers to a filler substance with different material properties from the first backfill. This can be achieved using building foam materials, such as foamed concrete or polyurethane foam. This material reduces the load on the solidified structure through its low-density characteristics, while simultaneously absorbing stress generated by soft rock deformation through its compressibility.

[0069] Preset strength refers to the mechanical properties of the first backfill material to withstand subsequent construction loads, which can be achieved through compressive strength testing or elastic modulus determination. This property ensures that the construction of the second backfill material will not damage the existing support structure.

[0070] After the first backfill material has solidified to a stable load-bearing capacity, the material supply system is switched using 3D printing equipment to deposit the second backfill material layer by layer onto the surface of the first backfill material. During the solidification process, the second backfill material forms an interface bond with the first backfill material. Its low modulus characteristics allow for elastic deformation during continuous deformation of the soft rock, thereby avoiding stress concentration. At the same time, the second backfill material fills the remaining space to form a complete closed structure, achieving graded dissipation of deformation energy through the stiffness gradient distribution of the two materials.

[0071] In this embodiment, through phased construction and differentiated material performance design, the first backfill body undertakes the main supporting function, while the second backfill body serves as a deformation buffer layer, forming a rigid-flexible composite structural system. This layered construction method effectively blocks the transmission path of deformation stress and solves the problem of disturbance to the solidified structure caused by secondary construction.

[0072] This application achieves graded load-bearing and deformation coordination of the backfill structure, preventing cracking of the backfill caused by deformation of soft rock tunnels. By utilizing the compressibility of the second backfill material to absorb geological displacement, it avoids structural failure caused by continuous deformation of a single rigid material, while simultaneously ensuring the construction safety of both backfilling operations.

[0073] In one embodiment, the second backfill material is a building foam material.

[0074] Specifically, foamed building materials refer to lightweight engineering materials with a porous structure and a lower density than conventional concrete. These materials can be made using foamed concrete, expanded perlite, or polyurethane foam. Through physical or chemical foaming processes, these materials form a honeycomb-like porous structure with a porosity of 50%-90%, and their elastic modulus is two orders of magnitude lower than that of conventional concrete. During backfilling, this material absorbs the deformation energy of the surrounding rock through the elastic deformation of its porous structure, reducing the risk of stress concentration within rigid structures.

[0075] After the first backfill material was completed and reached its preset strength, building foam material was used to construct the second backfill material. This material was sprayed in layers using 3D printing equipment into the voids between the first backfill material and the surrounding rock, utilizing its self-leveling properties to fully fill the irregular spatial interfaces. During the continuous deformation of the surrounding rock, the pore structure of the foam material undergoes recoverable elastic deformation, transforming the shear stress originally concentrated at the edge of the first backfill material into uniformly distributed compressive stress. Simultaneously, the low thermal conductivity of the foam material effectively prevents groundwater seepage from eroding the support structure.

[0076] Building foam materials, through the elastic deformation mechanism of their porous structure, enable the backfill to adapt to rock displacement within a range of 5-15 mm, avoiding brittle failure caused by stress concentration. Compared to the rigid structure formed by single-material backfilling in traditional processes, the rigid-flexible composite structure formed by this solution can reduce peak stress by approximately 30%-50%.

[0077] This application effectively solves the problem of backfill structure damage caused by continuous deformation of the geological body after backfilling in over-excavated areas of soft rock tunnels. The elastic deformation capacity of the building foam material allows the backfill to adapt to the displacement of the surrounding rock, avoiding cracking and failure of rigid materials; its lightweight properties reduce the additional load on the support structure, and the buffer layer formed by the porous structure can evenly distribute stress. This solution significantly extends the service life of the backfill while ensuring the stability of the support structure.

[0078] In one embodiment, the building foam material includes any one of foamed concrete, expanded perlite, or polyurethane foam.

[0079] Specifically, foamed concrete refers to a lightweight porous material formed by introducing closed pores into a cement matrix through physical or chemical methods. It can be achieved by mixing a foaming agent with cement slurry and pouring it into the concrete. Its honeycomb structure can absorb stress generated by the deformation of the surrounding rock. Expanded perlite refers to volcanic rock mineral particles that have undergone high-temperature expansion treatment. It can be achieved by combining expanded perlite powder with cementitious materials to form porous aggregates. Its inorganic porous properties can adapt to the continuous creep of soft rock tunnels. Polyurethane foam refers to a closed-cell foam material generated by the reaction of isocyanate and polyol. It can be achieved by using two-component polyurethane raw materials through high-pressure spraying and foaming. Its elastic deformation capacity can form a flexible support layer in complex over-excavation areas.

[0080] After the first backfill construction was completed, the second backfill material was selected as a building foam material with specific physical properties. Foamed concrete disperses the stress of the surrounding rock through its internal honeycomb structure, expanded perlite buffers geological deformation with its porous skeleton, and polyurethane foam absorbs displacement energy through elastic deformation. These three materials, through porosity adjustment, compressibility control, and elastic modulus matching, allow for moderate deformation while ensuring structural support, thereby alleviating the problem of rigid contact between the backfill and the surrounding rock. For example, during the continuous deformation stage of the surrounding rock, the polyurethane foam can undergo 20%-30% elastic deformation without cracking, demonstrating a significant advantage over the brittle failure mode of traditional concrete.

[0081] In this embodiment, the three foamed materials achieve dynamic coordination with the deformation of the surrounding rock through their own physical properties. Among them, the lightweight properties of foamed concrete reduce the additional load of the structure's self-weight on the surrounding rock, the fire resistance of expanded perlite meets the fire protection requirements of tunnels, and the rapid molding capability of polyurethane foam improves construction efficiency.

[0082] This application effectively solves the problem of deformation and damage caused by the rigidity of traditional backfill materials. The deformable characteristics of the foamed material allow the backfill to move synchronously with the surrounding rock, avoiding structural damage caused by stress concentration. The differentiated properties of the three materials provide options for different engineering conditions. For example, water-resistant polyurethane foam can be selected in environments with groundwater erosion, while fire-resistant expanded perlite material can be used in high-temperature sections, thus improving the adaptability of the backfill to geological conditions.

[0083] In one embodiment, step S100 includes:

[0084] S110. Scan the over-excavation area of ​​the soft rock tunnel to obtain the target backfill volume of the over-excavation area;

[0085] S120. Perform photography and video recording on the over-excavated area to collect and obtain the first current real-time deformation data of the over-excavated area.

[0086] Specifically, scanning the over-excavated area refers to acquiring the cavity's geometric parameters using a laser scanner or structured light 3D scanner. This can be achieved using a ground-based 3D laser scanning system, and its purpose is to quantify the backfill volume to match the actual cavity shape. Photographic and video recording operations involve using fixed industrial cameras or mobile camera robots to acquire multi-angle images of the surrounding rock surface. This can be achieved by deploying camera equipment along a pre-set track, and its purpose is to capture the displacement characteristics of the geological body surface. The preset shooting parameter set includes camera exposure time, focal length, and shooting interval time. For example, it can be set to acquire panoramic images every 30 minutes, which ensures the temporal consistency of data acquisition for deformation trend analysis.

[0087] During the scanning phase, point cloud data processing generates volumetric parameters for the over-excavated area, providing a benchmark for subsequent material usage calculations. In the image acquisition phase, feature matching algorithms for time-series images are used to extract the displacement vectors of the surrounding rock surface. Combined with the initial joint orientation recorded in the 3D benchmark model, the deformation rate and direction of the geological body are calculated. For example, when a clockwise deflection of the joint orientation is detected in a certain area, it can be determined that the area exhibits a shear deformation trend. The fusion analysis of deformation data and scanned volume provides dynamic input for the structural parameter design of the backfill body, allowing parameters such as bending angles to be adjusted based on real-time deformation characteristics.

[0088] In this embodiment, the combination of three-dimensional scanning and image sequence analysis enables digital reconstruction of the cavity morphology and full-domain monitoring of the deformation field. For example, it can identify joint surface slip phenomena that are difficult to capture by traditional methods, thereby improving the mechanical adaptability of the backfill structure design.

[0089] By quantifying the cavity volume and continuously tracking joint orientation changes, the geometric parameters of the backfill can be dynamically adapted to the deformation mode of the geological body. For example, when accelerated deformation is detected, the cross-sectional shape of the backfill can be adjusted in time to enhance shear resistance, thereby avoiding structural damage to the backfill due to subsequent deformation of the surrounding rock.

[0090] In one embodiment, step S120 includes:

[0091] S121. Use a preset camera device to perform photography and video recording on the over-excavated area to collect and obtain the first current real-time deformation data of the over-excavated area.

[0092] Specifically, the preset camera equipment refers to a pre-configured device with image acquisition function, which can be implemented using an industrial-grade high-definition camera or a 3D laser scanner. Its function is to ensure the stability and consistency of data acquisition through standardized equipment parameters.

[0093] Photography and video recording refers to the continuous or periodic recording of images of a target area. This can be achieved through multi-angle shooting or dynamic video recording. Its purpose is to capture the geological morphological changes of the over-excavated area at different points in time.

[0094] The first real-time deformation data refers to the quantitative indicators that reflect the instantaneous deformation state of the geological body in the over-excavated area. Specifically, it can be achieved by extracting joint orientation offset or surface displacement through image sequence analysis. Its role is to provide data support for the dynamic adjustment of backfill structure parameters.

[0095] Pre-set camera equipment periodically acquires images of the over-excavated area according to a pre-defined shooting path, for example, taking multiple angle shots at 5-meter intervals along the tunnel axis. The acquired image sequence is used to generate a 3D digital benchmark model of the over-excavated area using a 3D reconstruction algorithm. This model includes geological features such as the initial joint orientation. During subsequent construction, the continuously acquired current image set is compared with the benchmark model using image registration technology. For example, feature point matching algorithms are used to identify the offset angle and displacement of joint orientation, thereby calculating real-time data such as the average deformation rate. This data is fed back to the control terminal via a data transmission module, providing a basis for parameter adjustments in the backfilling scheme.

[0096] In this embodiment, continuous monitoring of deformation characteristics in the over-excavated area is achieved through automated image acquisition and dynamic analysis. For example, instantaneous displacement changes are captured by recording video at 30 frames per second, thereby significantly improving the timeliness and spatial resolution of deformation data. Through high-frequency, multi-dimensional image data analysis, the real-time deformation characteristics of the over-excavated area are identified, enabling parameters such as the bending angle and cross-sectional shape of the backfill to dynamically adapt to the deformation patterns of the geological body, effectively reducing the risk of cracking in the backfill caused by stress concentration due to deformation.

[0097] In one embodiment, step S121 includes:

[0098] S121a. Using a preset camera device to perform photography and video recording operations on the over-excavated area according to a preset shooting parameter set, so as to collect and obtain the first current real-time deformation data of the over-excavated area; wherein, the preset shooting parameter set includes a preset shooting path and preset shooting parameters.

[0099] Specifically, the preset shooting parameter set refers to a pre-defined combination of photographic and video parameters, which can be achieved by using fixed shooting angles, exposure times, resolutions, etc., to ensure the consistency of images acquired at different times. The image sequence refers to a continuous set of images arranged chronologically, which can be achieved through periodic or triggered shooting methods, used to record the morphological changes of the over-excavated area at different times. The target image set refers to a filtered and processed subset of images, which can be achieved using algorithms such as image denoising and distortion correction, used to eliminate interference factors and extract valid data. The three-dimensional digital benchmark model refers to a digital three-dimensional model reflecting the initial morphology of the soft rock tunnel, which can be achieved using laser scanning or photogrammetry techniques, used to establish an initial reference benchmark for the joint orientation of the geological body. The joint orientation model refers to a three-dimensional model describing the distribution and extension direction of joints within the geological body, which can be achieved through image feature extraction and spatial geometric reconstruction algorithms, used to quantify the structural characteristics of the geological body. The current image set refers to a set of images acquired in real time containing the current morphology of the geological body, which can be achieved through synchronized timestamps and spatial positioning techniques, used to record the dynamic deformation process. The current joint orientation refers to the real-time data on the distribution and extension direction of joints in geological bodies, which can be achieved through image segmentation and feature matching algorithms and used for difference analysis with the benchmark model.

[0100] A preset set of shooting parameters ensures the comparability of images acquired at different time points by fixing the shooting path and parameters. The image sequence, after denoising and correction, forms the target image set, providing standardized input data for the construction of the 3D digital benchmark model. The joint strike model in the 3D digital benchmark model establishes a spatial benchmark for geological deformation by extracting initial joint distribution characteristics. The current image set generated by continuous photogrammetry and video recording operations imports real-time joint strike data into the benchmark model through time synchronization and spatial registration. By comparing and analyzing parameters such as joint strike offset and crack propagation length, the real-time deformation data of the over-excavated area is quantified.

[0101] In this embodiment, by standardizing the data acquisition process through a preset parameter set and comparing time-series image sequences with the 3D model, the microscopic deformation characteristics of the geological body can be continuously captured, avoiding data gaps and improving the timeliness and accuracy of deformation analysis. By collecting and analyzing joint orientation changes in real time, dynamic data support is provided for adjusting the structural parameters of the backfill body, thereby reducing the risk of damage to the backfill body due to continuous deformation of the geological body.

[0102] In one embodiment, step S121a includes:

[0103] S11. Using a preset camera device, perform photography and video recording operations on the over-excavated area according to a preset shooting parameter set to obtain an image sequence of the over-excavated area.

[0104] Specifically, the preset shooting parameter set refers to the pre-set combination of image acquisition parameters, which can be achieved by using a fixed shooting angle, constant lighting conditions, and standardized resolution to ensure the spatiotemporal consistency of image data and provide a benchmark for subsequent modeling.

[0105] S12. Obtain the target image set of the over-drilled area based on the image sequence;

[0106] S13. Based on the target image set, establish a three-dimensional digital reference model of the soft rock tunnel; wherein, the three-dimensional digital reference model includes a joint orientation model of the geological body of the soft rock tunnel;

[0107] S14. Continuously perform photography and video recording on the soft rock tunnel to obtain the current image set corresponding to each acquisition time; wherein, each current image in the current image set records the current joint orientation of the geological body;

[0108] S15. Import the current image set into the three-dimensional digital benchmark model and compare and analyze the current joint orientation with the joint orientation model to obtain the first current real-time deformation data of the over-excavation area.

[0109] Specifically, the three-dimensional digital benchmark model refers to the digital representation of the tunnel spatial structure constructed based on the target image set. It can be realized through three-dimensional point cloud reconstruction algorithms. It includes the joint orientation model of the geological body, which is used to characterize the original structural features of the rock mass and provide a geometric benchmark for deformation analysis.

[0110] By acquiring image sequences using pre-set camera equipment with standardized parameters, the impact of environmental interference on data quality can be eliminated, allowing for the selection of a target image set as input for modeling. A three-dimensional digital benchmark model constructed based on this target image set fully records the joint orientation distribution in its initial state, forming a reference system for deformation analysis. The continuously acquired current image set is processed using image processing techniques to extract real-time joint orientation data. This data is then spatially registered and its differences calculated with the joint orientation model in the benchmark model, identifying the rock mass deformation displacement and direction, thereby outputting key parameters such as the average deformation rate.

[0111] In this embodiment, automated image acquisition and model comparison enable full-area coverage monitoring of deformation data, eliminating errors from manual measurement. Simultaneously, dynamic tracking of joint orientation allows for the capture of hidden deformation patterns such as rock mass surface slippage. This enables real-time acquisition of three-dimensional deformation characteristic data of the over-excavated rock mass, accurately identifying deformation rate and direction, providing data support for the dynamic adjustment of backfill structure parameters, and preventing backfill structure failure due to delayed or distorted deformation data.

[0112] The above description is merely an exemplary embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention specification and drawings under the technical concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A method for constructing 3D-printed backfill material for soft rock tunnels, characterized in that, Includes the following steps: The target backfill volume of the over-excavated area of ​​the soft rock tunnel and the first current real-time deformation data of the over-excavated area are collected; wherein, the first current real-time deformation data includes the average deformation rate; Based on the first current real-time deformation data, the target deformation time from deformation of the target geological body in the over-excavation area to filling the over-excavation area is obtained; When the target deformation duration exceeds a preset duration, a backfilling scheme for the over-excavated area is determined based on the first current real-time deformation data. The backfilling scheme includes the bending angle, bending radius, bending direction, cross-sectional area, and cross-sectional shape of the first backfill body required to resist the first current real-time deformation data. The bending angle refers to the angle between the printing path and the main deformation direction, used to disperse stress transmission paths. The bending radius refers to the radius of curvature between printing layers, used to enhance the structural bending resistance. The cross-sectional area refers to the cross-sectional dimension of a single layer of printed material, used to improve the structural load-bearing efficiency. In the over-excavated area, a 3D printing device is used to construct the first backfill body according to the backfilling scheme; wherein, the first backfill body is steel fiber concrete or quartz sand fiber concrete, and the first backfill body can resist the deformation of the target geological body; the second backfill body is building foam material, and the second backfill body serves as a deformation buffer layer, forming a rigid-flexible composite structural system. Once the first backfill material reaches the preset strength, the 3D printing equipment is used to continue applying a second backfill material to the over-excavated area to complete the backfilling operation of the over-excavated area.

2. The construction method for 3D-printed backfill material in soft rock tunnels as described in claim 1, characterized in that, The step of using 3D printing equipment to construct the first backfill body in the over-excavated area according to the backfilling plan includes: In the over-excavated area, the first backfill body is constructed using a 3D printing device and the first backfill material in accordance with the backfilling plan.

3. The construction method for 3D-printed backfill material in soft rock tunnels as described in claim 2, characterized in that, The first backfill material is steel fiber reinforced concrete or quartz sand fiber reinforced concrete.

4. The construction method for 3D-printed backfill material in soft rock tunnels as described in claim 3, characterized in that, The step of continuing to use the 3D printing equipment to apply a second backfill material to the over-excavated area after the first backfill material reaches a preset strength, in order to complete the backfilling operation of the over-excavated area, includes: Once the first backfill material reaches the preset strength, the 3D printing equipment is used to apply the second backfill material to the over-excavated area to complete the backfilling operation of the over-excavated area.

5. The construction method for 3D-printed backfill material in soft rock tunnels as described in claim 4, characterized in that, The second backfill material is building foam material.

6. The construction method for 3D-printed backfill material in soft rock tunnels as described in claim 5, characterized in that, The building foam material includes any one of foamed concrete, expanded perlite, or polyurethane foam.

7. The construction method for 3D-printed backfill material in soft rock tunnels as described in any one of claims 1 to 6, characterized in that, The steps of collecting the target backfill volume of the over-excavated area of ​​the soft rock tunnel and the first current real-time deformation data of the over-excavated area include: Scan the over-excavated area of ​​the soft rock tunnel to obtain the target backfill volume of the over-excavated area; Photographic and video recording operations are performed on the over-excavated area to collect and obtain the first current real-time deformation data of the over-excavated area.

8. The construction method for 3D-printed backfill material in soft rock tunnels as described in claim 7, characterized in that, The step of performing photographic and video recording operations on the over-excavated area to collect and obtain the first current real-time deformation data of the over-excavated area includes: The over-excavated area is photographed and videotaped using a preset camera device to collect and obtain the first current real-time deformation data of the over-excavated area.

9. The construction method for 3D-printed backfill material in soft rock tunnels as described in claim 8, characterized in that, The step of using a preset camera device to perform photographic and video recording operations on the over-excavated area to collect and obtain the first current real-time deformation data of the over-excavated area includes: The over-excavated area is photographed and videotaped using a preset camera device according to a preset shooting parameter set, so as to collect and obtain the first current real-time deformation data of the over-excavated area; wherein, the preset shooting parameter set includes a preset shooting path and preset shooting parameters.

10. The construction method for 3D-printed backfill material in soft rock tunnels as described in claim 9, characterized in that, The step of using a preset camera device to perform photographic and video recording operations on the over-excavated area according to a preset shooting parameter set, so as to collect and obtain the first current real-time deformation data of the over-excavated area, includes: Using a preset camera device and according to a preset shooting parameter set, the over-excavated area is photographed and videotaped to obtain an image sequence of the over-excavated area; Based on the image sequence, obtain the target image set of the over-dug area; Based on the target image set, a three-dimensional digital reference model of the soft rock tunnel is established; wherein, the three-dimensional digital reference model includes a joint orientation model of the geological body of the soft rock tunnel; The soft rock tunnel is continuously photographed and videotaped to obtain the current image set corresponding to each acquisition time; wherein, each current image in the current image set records the current joint orientation of the geological body; The current image set is imported into the three-dimensional digital benchmark model, and the current joint orientation is compared and analyzed with the joint orientation model to obtain the first current real-time deformation data of the over-excavated area.

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