Shallow-buried large-span roadway driving and anchoring integrated rapid driving and supporting method

Abstract

The invention discloses a shallow-buried long-span roadway driving and anchoring integrated rapid driving and supporting method. The method comprises the following steps that S1, the damage characteristics and surrounding rock stress of a long-span rectangular roadway are analyzed; s2, establishing different support scheme models; s3, the stability of the surrounding rock is analyzed, and which roof anchor rods are firstly constructed in the first supporting process is determined; s4, simulating and analyzing different support major cycle step pitch schemes, determining the forward tunneling length of the tunneling and anchoring all-in-one machine after the primary support, and starting to implement the secondary support of the anchor rod reversed loader; s4, carrying out first-time supporting according to the step 3: constructing partial anchor rods of a top plate and side parts by using a digging and anchoring integrated machine; and S5, follow-up secondary supporting is conducted, specifically, all the anchor rods and the anchor cables are completed through construction, and then one cycle operation is completed. In the numerical simulation process, the vertical stress, the plastic zone and the vertical displacement of the top plate of several construction schemes are compared, the optimal supporting scheme is determined according to the numerical calculation result, the supporting quality is ensured, and the supporting efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of coal mine mining, and specifically to a rapid tunneling and support method for integrated roadway driving and bolting in shallow-buried and large-span roadways. Background Art

[0002] During the roadway tunneling process, the time occupied by the support process is an important indicator to measure the tunneling efficiency, and the support speed has become the main factor restricting the roadway tunneling speed. At present, in the aspect of fully mechanized tunneling in China, there are mainly three construction techniques: tunneling with a roadheader and supporting with a bolt (cable) drill, tunneling with a continuous miner and supporting with a bolt (cable) drill, and integrated driving and bolting equipment. Among them, the integrated driving and bolting equipment is a construction technique that is more promising to achieve further rapid tunneling.

[0003] Shallow-buried and large-span roadways have shallow burial depths and thin bedrock layers. Due to the shallow burial depth, thick overlying loose layers, and large roadway spans, the roof is prone to bending deformation, generating large deflections, stress concentration occurs in the surrounding rock, and the distribution range of the plastic zone increases. When using integrated driving and bolting equipment to construct shallow-buried and large-span roadways, the existing support methods have unsatisfactory support quality and efficiency, resulting in the use of a roadheader for tunneling for a long time, and then a single-body bolt drill for support. Therefore, there is a lack of an effective method for rapid tunneling and support of integrated driving and bolting in shallow-buried and large-span roadways. Summary of the Invention

[0004] Aiming at the above existing technical deficiencies, the purpose of the present invention is to provide a rapid tunneling and support method for integrated roadway driving and bolting in shallow-buried and large-span roadways.

[0005] To solve the above technical problems, the present invention adopts the following technical solutions: The present invention provides a rapid tunneling and support method for integrated roadway driving and bolting in shallow-buried and large-span roadways, including the following steps: S1. Analyze the failure characteristics and surrounding rock stress of large-span rectangular roadways; S2. Establish models of different support schemes; Establish a numerical calculation model, and respectively simulate the stress evolution law of the surrounding rock, and the change laws of the plastic zone and displacement distribution under different support scheme conditions; S3. Analyze the stability of the surrounding rock and determine which roof bolts to construct first during the first support process; S4. Simulate and analyze different support large cycle step distance schemes, and determine how many meters to advance forward after the initial support of the integrated driving and bolting machine before implementing the secondary support of the bolt loader; S4. Conduct the first support according to step 3: Use the integrated driving and bolting machine to construct some bolts for the roof and sides; S5. Conduct subsequent secondary support: Use a hydraulic bolt trolley to complete all bolts and cables, and thus complete a cycle operation.

[0006] Furthermore, step S3 includes: S3.1. Analyze the vertical stress of the roadway; Conduct a simulation analysis on the tunneling support process to simulate the distribution characteristics of the vertical stress of the roof under different construction schemes of the roof bolts during the tunneling process; S3.2. Analyze the vertical displacement of the roof; Simulate several construction schemes of the roof bolts respectively, analyze the distribution characteristics of the vertical displacement of the horizontal section of the roof after tunneling under different schemes, and at the same time arrange a measuring point every few meters at the roof to monitor the vertical displacement of the roof; determine which scheme has the smallest surrounding rock deformation according to the vertical displacement of the roof; S3.3. Analyze the plastic zone of the roadway; Adopt several construction schemes of the roof bolts respectively, analyze the distribution of the plastic zone nephogram, and determine which scheme has relatively stable surrounding rock of the roadway.

[0007] The beneficial effect of the present invention is that: this method can, through numerical calculation of different support schemes, during the numerical simulation process, compare the vertical stress, plastic zone and vertical displacement of the roof of several construction schemes respectively, and determine the optimal support scheme according to the numerical calculation results, ensure the support quality and improve the support efficiency. Brief Description of the Drawings

[0008] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained according to these drawings.

[0009] Figure 1 It is a schematic diagram of the loose circle of the surrounding rock of the roadway provided by the embodiment of the present invention; Figure 2 It is a stress zoning diagram of the coal body on the side of the large-span section roadway provided by the embodiment of the present invention; Figure 3 It is a force analysis diagram of the roof rock beam of the large-span roadway provided by the embodiment of the present invention; Figure 4 It is a theoretical model diagram of the instability of the side of the large-span roadway provided by the embodiment of the present invention; Figure 5 It is a support simulation diagram under different construction conditions of the roof bolts provided by the embodiment of the present invention; Figure 6 It is a vertical stress nephogram of the 23303 belt conveyor gateway under different construction schemes provided by the embodiment of the present invention; Figure 7Vertical stress diagram of the shoulder angle for different roof bolt construction schemes provided by the embodiments of the present invention; Figure 8 Vertical displacement nephogram of the 23303 belt conveyor gateway under different roof construction schemes provided by the embodiments of the present invention; Figure 9 Vertical displacement diagram of different roof bolt construction schemes provided by the embodiments of the present invention; Figure 10 Distribution nephogram of the plastic zone of the 23303 belt conveyor gateway under different bolt construction schemes provided by the embodiments of the present invention; Figure 11 Cross-sectional view of the support scheme for the 23303 belt conveyor gateway provided by the embodiments of the present invention; Figure 12 Schematic diagram of the distribution of bolts and cable bolts in the support scheme for the 23303 belt conveyor gateway provided by the embodiments of the present invention.

[0010] Explanation of reference numerals: Bolt No. 1, Bolt No. 2, Bolt No. 3, Bolt No. 4, Bolt No. 5, Bolt No. 6, Bolt No. 7, Bolt No. 8, Bolt No. 9, Bolt No. 10, Bolt No. 11, Bolt No. 12, Bolt No. 13, Cable bolt No. 14. Detailed implementation manners

[0011] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than 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 efforts shall fall within the protection scope of the present invention. Embodiment

[0012] Taking the 23303 working face of Zhuanlongwan Coal Mine as an example, the roadway excavation width is 6.0 m, the net width is 5.8 m, the excavation height is 3.25 m, the net height is 3.0 m, and the excavation cross-sectional area is 19.5 m 2 , and the net cross-sectional area is 17.4 m 2 , which is a rectangular large-span cross-section roadway.

[0013] As Figure 1 shown, the rapid excavation and support method for the integrated mining and bolting of shallow-buried large-span roadways includes the following steps: S1. Deformation control principle of shallow-buried large-span cross-section roadways 1.1 Definition and failure characteristic analysis of large-span roadways Generally, the roadway height ranges from 2.5 to 4.0 m. If the span of the roadway is increased, the deflection of the roof will also increase accordingly, and at the same time, the risk of roof separation will be elevated, and the stability of the surrounding rock of the roadway will be reduced. For example, the roadway open-off cut belongs to a typical large-span roadway, and the risk of one-time drivage completion increases. Currently, most of them use the method of pilot tunnel plus rib expansion to complete it in two times. Through investigation and statistics, if the lateral pressure coefficient λ ≤ 1, a roadway span ≥ 5.5 m is called a large-span roadway; if the lateral pressure coefficient λ > 1, when the roadway span ≥ 5.0 m, it can be considered a large-span roadway, and its classification criteria are shown in Table 1.

[0014] Table 1 Classification criteria for roadway span

[0015] For the 23303 belt conveyor gateway in Zhuanlongwan Coal Mine, the buried depth is less than 200 m, the horizontal stress is significantly higher than the vertical stress, and its lateral pressure coefficient λ > 1. The roadway section excavation width is 6.0 m, and the net width is 5.8 m, belonging to a typical shallow-buried large-span roadway. Different roadway spans show great differences in their vertical stress, horizontal stress, and plastic zone, and different roadway support methods are adopted. When λ > 1, the critical value of a large-span roadway is 5.0 m. Exceeding this critical value, the roadway is prone to strong mine pressure manifestations, such as rib spalling, roof caving and other problems. At the same time, large-span roadways will be affected by factors such as their engineering geological conditions. After the roadway is excavated, the surrounding rock changes from a three-way stress state to a two-way stress state, the original rock stress is damaged, and the secondary stress is redistributed. The rock layer near the roadway surface is mainly affected by the horizontal stress. When the deformation load exceeds the strength of the rock layer on the roadway surface, the rock layer is damaged, the roof is prone to instability, and then the "roof caving" phenomenon occurs. If the roadway is in an area with more structures, the mine pressure manifestation is more intense. After the roadway is excavated, the surrounding rock mass is damaged, the overall strength is reduced, the number of fissures increases, and a broken zone, plastic zone, elastic zone, and original rock stress zone appear inside the roadway, forming a surrounding rock loosening circle centered on the roadway, as Figure 1 shown.

[0016] Due to the existence of the surrounding rock loosening circle, the tangential stress near the roadway decreases significantly as it moves away from the roadway. Generally, after 3 to 5 times the roadway span, the surrounding rock gradually returns to the original rock stress state. After the roadway deforms, it begins to interact with the bolt and cable support body. As time increases, generally two results occur. One is that the support body can resist the deformation of the roadway surrounding rock and effectively prevent further damage to the roadway, and the roadway surrounding rock is controlled; the other is that the strength of the support body is small or the support is not timely, and the roadway quickly becomes unstable and finally fails. The redistribution of secondary stress is a process of continuous stress adjustment. The excavation and unloading of the roadway cause obvious reduction of parameters such as the strength and elastic modulus of the rock mass, and the range of the plastic zone gradually spreads to the deep part, resulting in the instability of the roadway.

[0017] 1.2 Stress Analysis of Surrounding Rock in Large-Span Rectangular Roadways The 23303 Belt Conveyor Gateway in Zhuanlongwan Coal Mine is a typical shallow-buried large-span roadway. According to the theory of the maximum horizontal principal stress, the excavation of the roadway leads to the redistribution of secondary stress. The horizontal stress transfers to the roof and floor of the roadway, while the vertical stress mainly acts on the two sides of the roadway. The interaction between the vertical stress and the horizontal stress causes phenomena such as roof subsidence, floor heave, and strata separation in the deep part of the roadway, which are the manifestations of mine pressure.

[0018] After the excavation of the large-span roadway, the stress state of the rock mass is shown in Figure 2. The roof of the roadway can be simplified as a simply supported beam. After the excavation of the roadway, the overlying strata pressure transfers to the two sides of the roadway, causing the pressure on the two sides of the roadway to gradually increase. At the same time, the horizontal stress generated on the two sides of the roadway is superimposed with the original rock stress, resulting in stress concentration, and then the phenomenon of increasing convergence of the two sides of the roadway appears. The stress on the roof and floor close to the roadway surface is the largest, and stress concentration is likely to occur at the shoulder sockets and floor corners. The criterion for the instability of large-span roadways is mainly based on the fact that the tensile stress on the roof and floor rock mass of the roadway is greater than the tensile strength of the rock mass itself.

[0019] Since the roof rock is sedimentary rock, under the action of the stress parallel to the bedding plane in the horizontal direction, the large-span roadway is prone to strata separation and large deflection deformation, and then the roof fractures and collapses. The strata separation and large deformation of the layered roof develop gradually from shallow to deep. Simplify the multi-layer roof of sedimentary rock into a deflection model of a rock beam. First, consider the first rock beam, then the critical load P cr for the instability with deflection deformation is:[[]] ; In the formula, P cr — the critical load for the instability with deflection deformation; µ — the length coefficient of the roadway rock beam. If the rock beam is fixed at both ends of the roadway, 0.5 is selected; B — the span of the roadway; I — the moment of inertia of the central axis of the roadway rock beam. The critical stress σ cr for the instability failure of the rock beam directly adjacent to the roadway surface is:[[]] ; In the formula, σ cr — the critical stress for the instability failure of the rock beam.

[0020] It can be seen from the formula that the critical instability of the roadway is related to the cross-sectional shape of the roadway and the span-to-height ratio. The larger the span-to-height ratio, the more prone the roadway is to instability. On the contrary, the roadway is more likely to remain stable. Under the action of roadway load and horizontal stress, the condition for the deflection deformation of the rock beam is:[[]] ; Therefore, when the roof rock beam is thick enough, it generally will not be completely damaged. In addition, due to the stress generated by the horizontal stress as the roof rock beam of the roadway bends, when the roadway has a large span, the rotation space is relatively large, and large deflection deformation and rock beam breakage are also likely to occur.

[0021] After the roof rock beam near the surface of the large-span roadway breaks, the force on the second-layer roof is transmitted through the first layer, and the length of the roof rock beam changes. However, the thickness and lithology of the rock beam are different from those of the first layer, so its force, bending moment, and moment of inertia of rotation all change. If damage occurs, it will continue to be transmitted upward until the rock beam does not break.

[0022] Next, analyze the instability of the roadway rib. After the surrounding rock of the roadway becomes a two-way stress state, it needs to pass through the support body to reach a new balance again. The calculation model of the roadway rib is as shown.

[0023] The calculation of the roadway roof load is based on the following formula: ; In the formula: q1 — the load applied to the roof of the large-span roadway; γ — the unit weight of the overlying rock mass of the large-span roadway; a — 1 / 2 of the span of the large-span roadway; H — the height of the large-span roadway; β — the rib slip angle; f — the Proctor coefficient of the rock.

[0024] If instability occurs in the roadway rib, then the gravity of the overlying rock layer in the vertical direction at any point of the roadway is: ; According to the Mohr-Coulomb criterion, the condition for the roadway rib not to be unstable should be satisfied: ; If the roadway rib is broken, the cohesion of the rock mass can be considered to be 0, then the condition for the roadway not to be unstable is: ; In the formula, σ1 — is the maximum principal stress; σ3 — the support resistance provided by the large-span roadway. Combining the above formulas and sorting them out, we can get: ; Considering the maximum lateral stress, when h = H, then by combining the equations, we can get: ; If the roadway is not unstable, it is necessary to ensure that the support resistance p ≥ σ 3max .

[0025] (2) Establishment of different support scheme models 2.1 Numerical model construction This numerical calculation takes the 23303 glue conveyor roadway as the engineering background. Similarly, a numerical calculation model is established by FLAC software to simulate the stress evolution law of the surrounding rock, the plastic zone and the displacement distribution law under different support schemes. According to the actual buried depth of 168.28 m of the 23303 glue conveyor roadway in Zhuanlongwan Coal Mine, the overlying rock load is applied. The bottom of the roadway is fixed at the vertical boundary, and the lateral pressure coefficient is applied on the left and right. The overall roadway adopts the Mohr-Coulomb model, and the occurrence and mechanical parameters of the rock strata are the same as those in Chapter 3, as shown in Table 2.

[0026] Table 2 Physical and mechanical parameters of coal and rock mass for numerical simulation

[0027] 2.2 Simulation content (1) After simulating the excavation of the roadway, during the first support process, which bolts should be constructed first by the roadheader-anchoring machine during construction to better maintain the stability of the roof and keep the rapid excavation effect of the roadway. (2) Simulation schemes: Scheme 1 - construct two bolts on the roof first (numbered 1, 6), Scheme 2 - construct two bolts on the roof first (numbered 3, 4), Scheme 3 - construct four bolts on the roof first (numbered 1, 3, 4, 6), Scheme 4 - construct four bolts on the roof first (numbered 2, 3, 4, 5). At the same time, only one bolt is constructed at each of the left and right sides (numbered 7, 10). Through numerical calculation, compare the differences in the vertical stress, vertical displacement at the shoulder angle of the roadway when different bolts are constructed, and select the most suitable construction method. The specific construction scheme is shown in Table 3. The specific construction is shown in Figure 5. (3) Fix a cutting cycle step distance of 5 m (the head 0 - 5 m is the empty roof area without support). The bolts constructed on the roof are left-handed non-longitudinal ribbed steel bolts with a specification of Φ20×2200 mm, and the row spacing is 1100 mm. For the top bolt on both sides, the bolts in the coal pillar side adopt ribbed steel bolts with a specification of Φ18×1800 mm, and the row spacing is 1100 mm; the bolts in the mining side adopt fiberglass bolts with a specification of Φ18×1800 mm, and the row spacing is 1100 mm.

[0028] Table 3 Different construction schemes of roof bolts

[0029] Compare the above four different construction schemes of roof bolts, and focus on comparing their vertical stress, plastic zone, control of roadway shoulder angle, and distribution characteristics of roof displacement.

[0030] (3) Stability analysis of the surrounding rock of the 23303 glue conveyor roadway 3.1 Analysis of roadway vertical stress Simulate and analyze the tunneling support process of the 23303 glue transportation and ventilation gateway, and simulate the vertical stress distribution characteristics of the roof under different construction schemes of roof bolts during tunneling (that is, which several roof bolts are constructed first during the first support process has a better effect on maintaining the stability of the roadway). Make a vertical section along the central axis of the roadway and a horizontal section in the middle of the roadway side. When the roof support schemes are: Scheme 1 - construct two roof bolts first (numbered 1, 6), Scheme 2 - construct two roof bolts first (numbered 3, 4), Scheme 3 - construct four roof bolts first (numbered 1, 3, 4, 6), Scheme 4 - construct four roof bolts first (numbered 2, 3, 4, 5), the vertical stress distribution nephogram of the roadway surrounding rock is shown in Figure 6. At the same time, a measuring point is arranged every 5 m at the shoulder angle of the 23303 glue transportation and ventilation gateway, and the vertical stress at its shoulder angle position is shown in Figure 7.

[0031] It can be seen from the figure that there is an elliptical stress ring area in the surrounding rock of the roadway after tunneling. From the roadway surface to the depth, including both sides and the heading face direction, there appear a broken zone, a plastic zone, an elastic zone, and a virgin rock stress zone in sequence. During the roadway tunneling period, the vertical stress distribution characteristics of the roadway surrounding rock are less affected by the large cycle step distance of support. For different construction schemes of roof bolts, during the rapid tunneling of the roadway, the stability of the roadway surrounding rock, especially the support effect on the roadway shoulder angle, is also different. Comparing the four construction schemes of the roof, when bolts numbered 1, 3, 4, and 6 are constructed on the roof of the 23303 glue transportation and ventilation gateway, the shoulder angle of the roadway is better controlled, and the maintenance effect on the middle roof of the roadway is also better. Therefore, under the operation support of the support scheme of constructing bolts numbered 1, 3, 4, and 6 on the roof, the safety of the roadway roof and the stability of the surrounding rock can be satisfied.

[0032] 3.2 Roof vertical displacement analysis Respectively simulate the vertical displacement distribution characteristics of the horizontal section of the roof of the 23303 glue transportation and ventilation gateway after tunneling when the construction schemes of roof bolts are: Scheme 1 - construct two bolts (numbered 1, 6), Scheme 2 - construct two bolts (numbered 3, 4), Scheme 3 - construct four bolts (numbered 1, 3, 4, 6), Scheme 4 - construct four bolts (numbered 2, 3, 4, 5), as shown in Figure 8. At the same time, a measuring point is arranged every 5 m on the roof of the 23303 glue transportation and ventilation gateway to monitor the vertical displacement of the roof, and the vertical displacement of its roof is shown in Figure 9.

[0033] As can be seen from Figure 8, the influence of roadway excavation disturbance on the surrounding rock of the roadway is small. Under the four different roof bolt construction schemes, the surrounding rock deformation of the 23303 belt conveyor gateway is small. Generally speaking, when four bolts (bolt No. 1, 3, 4, and 6) are constructed on the roof, the surrounding rock deformation of the gateway is the smallest. The roof deformation is relatively small within a certain range behind the driving face, indicating that the support section constructed by the continuous miner and the driving face form a "ring structure". Constructing bolts 1, 3, 4, and 6 during the initial bolt construction can meet the stability of the surrounding rock of the roadway. Comparing the construction of bolts 1, 3, 4, and 6 with the construction of bolts 2, 3, 4, and 5, the deformation in the middle of the roof remains basically unchanged, and the deformation at the roof shoulder angle becomes smaller, further indicating that the initial construction of bolts 1, 3, 4, and 6 is the optimal bolt for the initial construction during the rapid driving of the continuous miner. The support strength of the continuous miner construction can meet the safety control requirements of the roadway roof.

[0034] 3.3 Analysis of roadway plastic zone After adopting four schemes for the construction of roof bolts respectively, the contour map of the plastic zone distribution of the 23303 belt conveyor gateway is shown in Figure 10.

[0035] As can be seen from Figure 10, the development range of the plastic zone characterizes the stress and bearing state of the surrounding rock mass. As the cycle step distance increases, the range of the plastic zone of the roadway surrounding rock does not show an expanding trend, indicating that the support state during the rapid driving operation can already meet the support requirements of the roadway surrounding rock. At the same time, it can be seen that when only bolts 1 and 6 are constructed or bolts 3 and 4 are constructed, the contour map of the plastic zone distribution of the 23303 belt conveyor gateway is larger, and the support effect at the roof shoulder angle is poor; when bolts 2, 3, 4, and 5 are constructed, the middle part of the roof is well controlled, but the support effect at the gateway shoulder angle is poor, which is not conducive to the rapid construction of the roadway continuous miner; when bolts 1, 3, 4, and 6 are constructed, the support effect at the gateway shoulder angle is good, and the roadway surrounding rock is relatively stable, which has a good effect on the rapid driving of the continuous miner in the 23303 belt conveyor gateway.

[0036] (4)Determination of roadway support parameters for the 23303 belt conveyor gateway By simulating and analyzing different support large cycle step distance schemes (that is, determining how many meters to advance forward after the initial support of the continuous miner before implementing the secondary support of the bolt conveyor), the optimal support scheme during the continuous miner operation, and the surrounding rock stability of the 23303 belt conveyor gateway, the final support scheme for the 23303 belt conveyor gateway is as follows: Roof: Two steel strands of Φ17.8×6000mm, row and column spacing of 2400×3300mm; six bolts of Φ20×2200mm, row and column spacing of 1000 (1300)×1100mm; welded with 5mm steel bars according to a grid of 2300×1200mm, with one grid overlap between nets, and connected with 10# iron wire every 300mm. Coal pillar side: Three threaded steel bolts of Φ18×1800mm are used, with row and column spacing of 800×1100mm, and a steel wire mesh is hung. Mining side: Three FRP bolts of Φ20×1800mm are used, with row and column spacing of 1200×1100mm, and a plastic mesh is hung. The original support plan for the roadway is shown in Figure 11.

[0037] The support operation for the cross-section of the 23303 belt conveyor gateway is divided into two links. For the first support, a roadheader-anchoring machine is used to install some bolts on the roof and sides. For the subsequent second support, a hydraulic bolt rig is used to complete all bolts and cables. As shown below, for the first support, a roadheader-anchoring machine is used to install four bolts on the top (numbered 1, 3, 4, 6) and two bolts on the sides (numbered 7, 10). For the second support, a hydraulic bolt rig is used to install two bolts on the top (numbered 2, 5), four bolts on the sides (numbered 8, 9, 10, 12) and two cables on the roof (numbered 13, 14), thus completing one cycle of operation.

[0038] Obviously, those skilled in the art can make various modifications and variations to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention is also intended to include these modifications and variations.

Claims

1. A shallow buried large span tunnel excavation and anchoring integrated rapid excavation support method, characterized in that: The following steps are involved: S1. Analyze the failure characteristics and surrounding rock stress of large-span rectangular tunnels; S2. Establish models of different support schemes; A numerical calculation model is established to simulate the stress evolution law of the surrounding rock and the change law of the plastic zone and displacement distribution under different support schemes. S3. Analyze the stability of the surrounding rock and determine which top plate anchors to construct first during the first support process; S4. Simulate and analyze different support large cycle step distance schemes to determine how many meters the anchor drill needs to dig forward after the initial support to start the secondary support of the anchor transfer machine; S4, perform the first support according to step 3: use the integrated digging and anchoring machine to construct some anchor rods of the top plate and the side; S5. Subsequent second support: Use the hydraulic anchor trolley to complete all anchor rods and anchor cables, thus completing a cycle of operations.

2. The shallow buried large span tunnel excavation and anchoring integrated rapid excavation support method according to claim 1 is characterized in that: The step S3 comprises: S3.

1. Analyze the vertical stress in the tunnel; Simulate and analyze the excavation support process, and simulate the vertical stress distribution characteristics of the roof under different construction schemes of the roof anchor during excavation; S3.2, analyze the vertical displacement of the top plate; Simulate several construction schemes of roof anchor bolts, analyze the vertical displacement distribution characteristics of the horizontal section of the roof after excavation under different schemes, and arrange a measuring point every few meters on the roof to monitor the vertical displacement of the roof; determine which scheme has the smallest surrounding rock deformation according to the vertical displacement of the roof; S3.3, Analyze the plastic zone of the roadway; Several construction schemes of roof anchors were adopted respectively, and the distribution of construction plastic zone cloud map was analyzed to determine which scheme has more stable tunnel surrounding rock.

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