A rock mass beam structure, its method for resisting floor heave deformation and construction method

Abstract

The present invention relates to the technical field of railway tunnel engineering construction, and particularly relates to a rock mass beam structure, a method for resisting floor heave deformation thereof, and a construction method. The rock mass beam structure includes a plurality of operation galleries arranged in a strip shape. An isolation groove is arranged following the shape of the bottom of the operation gallery. The isolation groove includes a vertically arranged groove channel, and the groove channel is filled with a flexible medium. Using the operation gallery and the isolation groove as boundaries, a beam structure is separated and formed. The beam structure is provided with deformation adjustment holes and / or reinforcement structures and / or prestressed anchor cables. By isolating the floor heave deformation caused by horizontal ground stress, and using the self-weight and compressive strength of the rock mass to resist the floor heave deformation of the rock mass, and by providing a free face, effective guidance and control of the floor heave deformation are realized. At the same time, active settlement of the rock mass is realized. When applied to a tunnel, flexible construction can be carried out during the operation period of the tunnel, dynamic treatment of the floor heave deformation of the rock mass is realized, which has good flexibility and good social and economic value.

Description

Technical Field

[0001] The present invention relates to the technical field of railway tunnel engineering construction, and particularly relates to a rock mass beam structure, a method for resisting floor heave deformation thereof, and a construction method thereof. Background Technique

[0002] The arching of the ballastless track in the tunnel mainly results from the floor heave deformation of the tunnel. The floor heave deformation of the tunnel is a complex physical and mechanical phenomenon, and there are mainly three reasons: groundwater, swelling rock mass at the tunnel bottom, and in-situ stress.

[0003] Currently, there are mainly four categories of methods for treating the floor heave disease of the tunnel: (1) By adjusting the curvature and thickness of the tunnel invert structure, strengthening the filling layer between the ballastless track and the invert and the reinforcement of the invert structure, thereby improving the stiffness of the tunnel bottom structure, restraining the floor heave deformation of the tunnel, and then controlling the arching of the ballastless track; (2) Using prestressed long bolts or cables to anchor the rock mass at a certain depth at the bottom of the tunnel, and at the same time injecting grout to reinforce and improve the strength of the rock mass at the tunnel bottom, so as to reduce the floor heave deformation of the tunnel, and then control the arching of the ballastless track; (3) Setting materials or structures for absorbing deformation outside the tunnel bottom invert or between the invert and the ballastless track to absorb or isolate the floor heave deformation of the tunnel, and then control the arching of the ballastless track; (4) Setting pressure relief holes or pressure relief grooves around the tunnel to reduce the in-situ stress level at the bottom of the tunnel, so as to release the in-situ stress and reduce the floor heave deformation.

[0004] However, these existing methods all have certain problems: (1) Improving the stiffness of the tunnel bottom structure in this closed thin-walled statically indeterminate structure of the tunnel is likely to cause the overall stiffness imbalance of the tunnel structure, stress concentration will occur at the bottom, and as the stress increases, the difficulty of deformation control increases, so the effect is very limited; (2) Improving the stiffness of the rock mass at the tunnel bottom is controlled by geological factors such as joints and fissures of the rock mass at the tunnel bottom and creep of the rock mass at the tunnel bottom. At the same time, the dispersion effect of prestress also results in poor anchoring effect on the deep rock mass at the tunnel bottom, making it difficult to achieve the expected purpose, and there is also a risk of loosening of the prestressed structure; (3) It is difficult to accurately set the reserved deformation amount in a limited space for the measures of absorbing and isolating deformation, and the materials and structures for absorbing deformation also have deformation limits; it is difficult to accurately determine the stable and non-deforming rock stratum when isolating deformation; (4) The measures for releasing in-situ stress are difficult to accurately control the magnitude and direction of release, and are likely to cause damage to the bearing structure in the rock mass at the tunnel bottom around the tunnel.

[0005] With the development of railway construction in China, the number of railway tunnels put into operation is increasing continuously. The occurrence probability of tunnel floor heave disease is increasing, the rectification difficulty is rising continuously, but the rectification effect is not satisfactory, which seriously affects the safety of railway operation. At the same time, the rectification process of tunnel floor heave disease will affect the high-speed rail operation in the tunnel, and even requires the interruption of operation, bringing huge operation losses. In addition, once the above existing rectification measures are completed, it is difficult to add rectification measures. When the floor heave deformation occurs again, only re-construction can be carried out, resulting in low rectification flexibility.

[0006] Therefore, there is an urgent need for a technical solution at present to reduce and quickly and effectively rectify the tunnel floor heave disease, ensure the safety of railway operation and reduce operation losses. Summary of the Invention

[0007] The purpose of the present invention is to provide a rock mass beam structure, its anti-floor heave deformation method and construction method for the technical problems that the existing tunnel floor heave disease cannot be effectively rectified, affecting the safety of railway operation, and interrupting the operation in the tunnel for rectification will cause huge operation losses.

[0008] In order to achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0009] A rock mass beam structure includes a number of operation galleries arranged in a strip shape. An isolation groove is arranged following the shape of the bottom of the operation gallery. The isolation groove includes a vertically arranged channel, and the channel is filled with a flexible medium. The operation gallery and the isolation groove are used as boundaries to separate and form a beam structure. The beam structure is provided with deformation adjustment holes and / or reinforcement structures and / or prestressed anchor cables, and the deformation adjustment holes, the reinforcement structures and the prestressed anchor cables are connected to the operation gallery.

[0010] A rock mass beam structure of the present invention divides the lateral boundary of the rock mass beam structure in the vertical direction through an isolation groove, isolates the horizontal ground stress, enables the rock mass within the depth range of the isolation groove to be not stressed in the horizontal direction, forms a beam structure that is not subject to horizontal loads and is only subject to the bottom heave load below, and the beam structure can be applied below structures such as tunnels that are prone to bottom heave deformation, isolates the bottom heave deformation caused by the horizontal ground stress, and replaces concrete as a compressive material, makes full use of the self-weight and compressive strength of the rock mass to resist the bottom heave deformation of the rock mass. At the same time, the isolation groove and the operation tunnel provide a free face for the deformation of the rock mass, relieve the lateral constraint of the beam structure, guide the deformation of the rock mass in the lateral direction, reduce the vertical development, and induce the vertical bottom heave deformation to transform into the horizontal expansion deformation, so as to effectively guide and control the amount of bottom heave deformation. In addition, by arranging a reinforcement structure in the beam structure, the stiffness can be further improved, the self-weight can be increased, and the effect of resisting bottom heave deformation can be improved. At the same time, by arranging deformation adjustment holes, the rock mass near the beam structure can be removed to achieve the effect of active settlement of the rock mass, and the bottom heave deformation that has occurred in the rock mass in the area of the beam structure can be corrected. By arranging prestressed anchor cables to provide prestress for the rock mass beam structure, the beam structure can be deformed downward through the prestress action to achieve the function of active settlement and counteract the bottom heave deformation. When a rock mass beam structure of the present invention is applied to the ballastless track in a tunnel or an embankment section, it can not affect the normal operation of the train, can be flexibly constructed during the train operation period, realizes the dynamic treatment of the bottom heave deformation of the rock mass, can continuously add treatment measures, has good flexibility, and has good social and economic value.

[0011] As a preferred embodiment of the present invention, the reinforcement structure includes a plurality of steel pipe piles horizontally arranged in the beam structure. The steel pipe piles include reinforced concrete cast-in-place piles. The steel pipe piles include steel pipes and steel cages arranged in the steel pipes. The steel pipe piles are used for reinforcing the rock mass beam structure. The ends of the steel pipe piles are connected to the operation tunnel to improve the flexural stiffness of the rock mass beam structure under the action of the bottom heave load so as to resist the bottom heave deformation.

[0012] As a preferred embodiment of the present invention, the prestressed anchor cable includes a straight section and a curved section. The end of the straight section is an anchoring end, and the end of the curved section is a tensioning end. The projection of the anchoring end on the vertical projection plane is higher than that of the tensioning end. A plurality of the prestressed anchor cables are arranged alternately along the extending direction of the operation tunnel. The alternate arrangement means that in any operation tunnel, the anchoring end and the tensioning end are alternately arranged at intervals along the extending direction of the operation tunnel.

[0013] As a preferred embodiment of the present invention, the reinforcement structure and the prestressed anchor cables are arranged alternately at intervals along the extending direction of the operation tunnel.

[0014] As a preferred embodiment of the present invention, a number of drainage holes are provided on the side wall of the working tunnel. The drainage holes are inclined. A drainage ditch is arranged in the working tunnel, and the drainage ditch is located below the drainage holes. The drainage holes are arranged on the side wall of the working tunnel far from the beam structure, and are used to drain the groundwater in the surrounding rock mass into the drainage ditch in the working tunnel, reduce the surrounding groundwater level, and eliminate the floor heave deformation caused by water pressure.

[0015] As a preferred embodiment of the present invention, all the working tunnels are set at the same or similar elevations, the bottom surfaces of all the isolation grooves are kept at a unified elevation, and the relative connection deformation adjustment holes, reinforcement structures and prestressed anchor cables are arranged between adjacent working tunnels. According to the actual situation, the specific composition structure of the rock mass beam structure can be adjusted to make the rock mass beam structure adapt to the use environment, and the formed rock mass beam structure under the combined action of multiple treatment measures has the optimal anti-floor heave deformation effect.

[0016] As a preferred embodiment of the present invention, it is applied to the rock mass inside the bottom of a tunnel or a subgrade. Two working tunnels are distributed on both longitudinal sides of the tunnel or the subgrade. The working tunnels are provided with bolt-shotcrete support. The working tunnels are connected to the external space of the rock mass through auxiliary tunnels. The isolation groove is arranged at the midline position of the bottom of the working tunnel. At this time, the beam structure is located in the deep rock mass at the bottom of the tunnel or the subgrade. The rock mass above the beam structure exerts a downward load on the beam structure, which can further improve the anti-floor heave deformation effect of the rock mass beam structure.

[0017] As a preferred embodiment of the present invention, it is applied to the embankment section. Two working tunnels are distributed on both longitudinal sides of the embankment. The tops of the working tunnels penetrate the ground surface. The working tunnels and the isolation grooves are combined to form a foundation pit structure, and the beam structure is formed between adjacent foundation pit structures. Further expand the application range of the rock mass beam structure.

[0018] As a preferred embodiment of the present invention, reinforced concrete structural slabs are respectively arranged on both longitudinal sides of the top surface of the beam structure. A number of uplift piles vertically penetrate the structural slabs and are anchored in the bedrock at the bottom of the beam structure. The structural slabs are arranged continuously or discontinuously along the extension direction of the foundation pit structure, and a number of the uplift piles are arranged along the extension direction of the foundation pit structure. The uplift piles provide a downward pulling force for the beam structure to resist the floor heave deformation below the beam structure. The function of the uplift piles is the same as that of the rock mass above the beam structure when the rock mass beam structure is applied to the deep rock mass at the bottom of a tunnel or a subgrade.

[0019] A method for resisting floor heave deformation of a rock mass beam structure, including a rock mass beam structure as described above, resisting the floor heave load below the beam structure by the self-weight of the beam structure; and / or forming deformation adjustment holes by drilling from the operation tunnel, extracting the rock mass, and causing the beam structure to undergo active settlement to eliminate floor heave deformation; and / or arranging a reinforcement structure in the deformation adjustment holes to adjust the flexural stiffness of the beam structure and resist the floor heave load below the beam structure; and / or arranging prestressed anchor cables in the beam structure to connect two adjacent operation tunnels, adjusting the flexural stiffness of the beam structure to resist the floor heave load below the beam structure, and applying prestress to the prestressed anchor cables to perform active settlement under prestress.

[0020] In the method for resisting floor heave deformation of a rock mass beam structure of the present invention, the self-weight is determined by the height, width, and length of the beam structure. The height is determined by the sum of the height of the isolation groove and the height of the operation tunnel in the vertical projection plane. The width is determined by the spacing between operation tunnels. The length is determined by the longitudinal extension length of the isolation groove. By adopting the above rock mass beam structure, the size, self-weight, and stiffness of the beam structure are positively correlated. The lower part of the beam structure is the source side of the load. The loads received by the beam structure are mainly the rock mass deformation load from the bottom upwards and the self-weight downwards. By adjusting the excavation depth of the isolation groove, the height of the beam structure can be increased, thereby achieving the effect of increasing the self-weight of the beam structure, offsetting the floor heave deformation load, and reducing the upward bending deformation; according to the actual situation, rectification measures can be flexibly added and combined to control the degree of active settlement, and the groundwater level in the area of the beam structure can be reduced by drilling drainage holes from the operation tunnel to eliminate floor heave deformation under water pressure; this method can be applied to the deep rock mass at the bottom of tunnels, roadbeds, etc., and can also be applied to the embankment section. It can achieve dynamic rectification of rock mass floor heave deformation without affecting normal traffic, and rectification measures can be continuously added according to the actual situation, with good flexibility and good social and economic value.

[0021] A construction method for a rock mass beam structure to resist the deformation of tunnel floor heave. The rock mass beam structure is continuously or intermittently arranged in the rock mass at the bottom of the tunnel. The rock mass beam structure is arranged at an interval from the bottom surface of the tunnel invert in the vertical direction. Two working galleries are symmetrically arranged on both sides of the tunnel cross-section. The working galleries are the same as or close to the tunnel extension direction, and the method includes the following steps: Step 1: Select an auxiliary gallery opening outside the mountain where the tunnel is located, construct the auxiliary gallery to the designed position of the working gallery, and excavate the working gallery; Step 2: Excavate an isolation groove at the center line of the bottom of the working gallery. The isolation groove is excavated by the method of slurry-supported drilling. After the drilling is completed, the slurry support is removed and a flexible medium is filled; Step 3: Drill holes in the working gallery into the rock mass to form deformation adjustment holes connecting adjacent two working galleries; Step 4: Arrange a reinforcement structure in the deformation adjustment holes formed in Step 3; In Step 1, the settlement deformation amount of the tunnel caused by the excavation of the working gallery is S1; In Step 2, the settlement deformation amount of the tunnel caused by the excavation of the isolation groove is S2; In Step 3, the settlement deformation amount of the tunnel caused by the formation of the deformation adjustment holes is S3; In Step 4, the rock mass beam structure can resist the bottom heave deformation amount of S4 after arranging the reinforcement structure.

[0022] A construction method for a rock mass beam structure to resist the deformation of tunnel floor heave according to the present invention forms the rock mass beam structure outside the tunnel. Under the condition of effectively guiding and controlling the deformation of the tunnel floor heave, it ensures the normal operation of the tunnel, belongs to a comprehensive scheme for rectifying the deformation of the tunnel floor heave, and has good adaptability to complex geological conditions.

[0023] As a preferred scheme of the present invention, when applied to a tunnel section where floor heave deformation has occurred, with the already occurred floor heave deformation amount D1 and the predicted subsequent floor heave deformation amount D2 of the tunnel, in Step 1, the designed starting position of the working gallery is the end with a lower elevation in the floor heave section of the tunnel;

[0024] If S1 + S2 + S3 ≥ D1, the already occurred floor heave deformation of the tunnel can be eliminated, and the ballastless track can be restored to the original elevation;

[0025] If S4 > D2, the subsequent floor heave deformation can be offset;

[0026] If S4 ≤ D2, drill prestressed anchor cable installation holes in the working gallery, install prestressed anchor cables and perform prestress tensioning. The settlement deformation amount of the tunnel caused by the prestress tensioning of the prestressed anchor cables is S5;

[0027] If S1 + S2 + S3 + S4 < (D1 + D2), apply tensile force to the prestressed anchor cables. If S4 + S5 > D2, stop applying tensile force to the prestressed anchor cables;

[0028] When applied to a section where floor heave deformation will continue to occur in the future, adjust the number of times of Step 3 and Step 4 to achieve the control of the elevation of the ballastless track; when applied to a section where floor heave deformation may occur, Step 3 and Step 4 are used as standby rectification measures.

[0029] As a preferred embodiment of the present invention, it further includes the steps of constructing drainage holes on the side wall of the operation tunnel away from the tunnel, and pouring a drainage ditch below the drainage holes in the operation tunnel to eliminate the groundwater pressure in the tunnel area.

[0030] In summary, due to the adoption of the above technical solutions, the beneficial effects of the present invention are as follows:

[0031] 1. A rock mass beam structure of the present invention isolates the horizontal ground stress through the isolation groove and the operation tunnel, reduces the floor heave deformation caused by the horizontal ground stress, forms a beam structure that is not affected by the horizontal load and is only affected by the floor heave load below, replaces concrete as the compressive material, makes full use of the self-weight and compressive strength of the rock mass, resists the floor heave deformation of the rock mass, and can be applied below structures such as tunnels that are prone to floor heave deformation, replacing the tunnel invert;

[0032] 2. A rock mass beam structure of the present invention provides a free face for the deformation of the rock mass through the isolation groove and the operation tunnel, relieves the lateral constraint of the beam structure, guides the deformation of the rock mass in the lateral direction, reduces the vertical development, and induces the transformation of the vertical floor heave deformation into the horizontal expansion deformation, realizing the effective guidance and control of the floor heave deformation amount;

[0033] 3. A rock mass beam structure of the present invention can remove the rock mass near the beam structure by setting deformation adjustment holes, realizing the active settlement effect of the rock mass and correcting the floor heave deformation that has occurred in the rock mass in the beam structure area;

[0034] 4. A rock mass beam structure of the present invention can further improve the stiffness and increase the self-weight by setting a reinforcement structure, improve the anti-floor heave deformation effect, effectively resist the future floor heave deformation, and realize the long-term stage dynamic adjustment of the floor heave deformation;

[0035] 5. A rock mass beam structure of the present invention can apply a downward pressure to the beam structure by setting prestressed anchor cables, which is opposite to the direction of the floor heave deformation, realizing the active settlement control and realizing the long-term real-time dynamic adjustment of the floor heave deformation;

[0036] 6. A method for resisting floor heave deformation of a rock mass beam structure of the present invention can be applied to the deep rock mass at the bottom of tunnels, subgrades, etc., and can also be applied to the embankment section. It can realize the dynamic rectification of the floor heave deformation of the rock mass without affecting the normal driving, and different rectification measures can be continuously added according to the actual situation, having good flexibility and good social and economic value;

[0037] 7. A method for resisting tunnel floor heave deformation of a rock mass beam structure of the present invention can realize the active guidance and control of the tunnel floor heave deformation during the operation of the tunnel, realize the dynamic rectification of the floor heave deformation of the rock mass, can continuously add rectification measures, has good flexibility, and has good social and economic value;

[0038] 8. A construction method for a rock mass beam structure of the present invention to resist the deformation of the tunnel floor heave. The rock mass beam structure is formed outside the tunnel. Under the condition of effectively guiding and controlling the deformation of the tunnel floor heave, the normal operation of the tunnel is ensured. It belongs to a comprehensive scheme for rectifying the deformation of the tunnel floor heave and has good adaptability to complex geological conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 is a schematic structural diagram of a rock mass beam structure of the present invention;

[0040] Figure 2 is a schematic elevation structural diagram of a rock mass beam structure of the present invention;

[0041] Figure 3 is a schematic plan structural diagram of a rock mass beam structure of the present invention;

[0042] Figure 4 is Figure 2 the schematic structural diagram of the A-A section in

[0043] Figure 5 is Figure 2 the schematic structural diagram of the B-B section in

[0044] Figure 6 is a schematic structural diagram of a rock mass beam structure of the present invention applied to a cutting section;

[0045] Figure 7 is a schematic structural diagram of a rock mass beam structure of the present invention applied to an embankment section;

[0046] Figure 8 is a schematic structural diagram of a rock mass beam structure of the present invention applied to the rock mass under the tunnel;

[0047] Figure 9 is a schematic elevation structural diagram of a rock mass beam structure of the present invention applied to the rock mass under the tunnel;

[0048] Figure 10 is a schematic plan structural diagram of a rock mass beam structure of the present invention applied to the rock mass under the tunnel;

[0049] Figure 11 is Figure 9 the schematic structural diagram of the C-C section in

[0050] Figure 12 is Figure 9 the schematic structural diagram of the D-D section in

[0051] Figure 13 is a schematic structural diagram of a prestressed anchor cable;

[0052] Figure 14It is the schematic diagram of a method for resisting floor heave deformation of a rock mass beam structure in the present invention before the induced deformation state;

[0053] Figure 15 It is the schematic diagram of a method for resisting floor heave deformation of a rock mass beam structure in the present invention after the induced deformation state;

[0054] Figure 16 It is the schematic diagram of a method for resisting floor heave deformation of a rock mass beam structure in the present invention in the deformation resistance state;

[0055] Figure 17 It is the schematic diagram of a method for resisting floor heave deformation of a rock mass beam structure in the present invention in the active settlement state.

[0056] Icon:

[0057] 11 - Isolation groove, 12 - Working tunnel, 13 - Prestressed anchor cable, 131 - Anchorage end, 132 - Tension end, 14 - Steel pipe pile, 15 - Drainage hole, 16 - Drainage ditch, 17 - Beam structure, 18 - Floor heave deformation load, 19 - Uplift pile, 21 - Tunnel invert, 22 - Tunnel invert filling layer, 23 - Ballastless track, 24 - Tunnel side wall, 25 - Tunnel vault, 26 - Tunnel, 27 - Subgrade, 28 - Embankment, 31 - Self - weight load of tunnel structure, 32 - Original vertical in - situ stress on the left and right sides of the tunnel, 33 - Original horizontal in - situ stress at the bottom of the tunnel, 41 - Single - hole settlement curve, 42 - Floor heave deformation curve of the tunnel before induced deformation, 43 - Floor heave deformation curve of the tunnel after induced deformation, 44 - Deformation curve of the tunnel bottom towards both sides after induced deformation. Detailed implementation manners

[0058] The present invention will be described in detail below with reference to the accompanying drawings.

[0059] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0060] Embodiment 1

[0061] As Figures 1 - 5 shown, a rock mass beam structure includes a plurality of working tunnels 12 arranged in a band shape in the rock mass. The bottom of the working tunnel 12 is provided with an isolation groove 11 in a conforming manner. The isolation groove 11 includes a groove channel vertically arranged in the rock mass, and the groove channel is filled with a flexible medium. The working tunnel 12 and the isolation groove 11 are used as the left and right boundaries, and the bottom of the isolation groove 11 is used as the lower boundary to partition and enclose a beam structure 17 in the rock mass.

[0062] Preferably, as Figure 1As shown in the figure, the operation tunnel 12 is a horseshoe-shaped space excavated in the rock mass. The cross-section of the operation tunnel 12 includes an upper semi-circular part and a lower rectangular part. It is connected to the position of the operation tunnel 12 by constructing an auxiliary tunnel from outside the mountain. After the operation tunnel 12 is excavated, the surrounding rock is supported by shotcrete with wire mesh and bolts.

[0063] Preferably, the operation tunnel 12 is longitudinally arranged in a straight line, and its extension direction can also be adjusted according to the actual situation. An isolation groove 11 is arranged along the center line at the bottom of the operation tunnel 12. The isolation groove 11 is a rectangular space excavated in the rock mass, which is consistent with the longitudinal extension direction of the operation tunnel 12, and the isolation groove 11 is filled with foam material.

[0064] In a rock beam structure of this embodiment, the operation tunnel 12 provides an operation space, and the isolation groove 11 divides the boundary of the rock beam structure in the vertical direction, playing a role in isolating the horizontal ground stress, so that the beam structure 17 within the depth range of the isolation groove 11 is not stressed in the horizontal direction. At the same time, the isolation groove 11 and the operation tunnel 12 jointly provide a free face for the deformation of the rock mass, relieve the lateral constraint of the beam structure 17, guide the rock mass deformation to develop laterally, reduce the upward development, and realize the induced deformation of the rock floor heave.

[0065] Specifically, the cross-sectional size, shape, extension length, distribution quantity along the extension direction, rock penetration depth, etc. of the operation tunnel 12 are all adjusted according to the construction conditions and application environment of the rock beam structure.

[0066] Furthermore, in some embodiments, the beam structure 17 is also provided with a deformation adjustment hole communicating with the operation tunnel 12. The deformation adjustment hole is formed by drilling from the operation tunnel 12 into the rock mass. The deformation adjustment hole can be used to connect two adjacent operation tunnels 12, or can be only used to connect any one operation tunnel 12. It can be formed by horizontal drilling, or can be drilled in any designed direction into the rock mass. During the drilling process, the rock mass can be extracted to form a hole, realizing the active settlement of the rock mass under the action of the upper load.

[0067] Furthermore, in some embodiments, the beam structure 17 is also provided with a reinforcement structure. The reinforcement structure is a reinforced concrete structure arranged in the deformation adjustment hole, which can prevent the excessive settlement of the rock mass under the action of the upper load, and can also be used as the non-prestressed reinforcement of the beam structure 17, improving the flexural stiffness of the beam structure 17 and realizing the active resistance to the deformation of the rock floor heave.

[0068] Preferably, for a rock mass beam structure in this embodiment, an induced deformation space is provided through the operation tunnel 12 and the isolation groove 11 structure to realize the induced deformation of the rock mass floor heave. The formed beam structure 17 resists the lower floor heave load. The deformation adjustment holes are formed by drilling to realize the active settlement of the rock mass. By arranging a reinforcement structure in the deformation adjustment holes, the flexural stiffness of the beam structure 17 is improved, the degree of active settlement is controlled, and the floor heave deformation is resisted, forming a comprehensive rock mass beam structure for resisting floor heave deformation, providing a new idea for preventing the upward arching deformation of the rock mass prone to floor heave deformation.

[0069] Specifically, in some embodiments, the reinforcement structure includes steel pipe piles 14. The ends of the steel pipe piles 14 are connected to the operation tunnel 12. The steel pipe piles 14 include steel pipes and steel reinforcement cages arranged inside the steel pipes. The outer diameter of the steel pipes is smaller than the diameter of the deformation adjustment holes, and concrete is poured into the deformation adjustment holes and the steel pipes to form, so as to realize the stiffness control of the rock mass after a certain degree of active settlement.

[0070] Embodiment 2

[0071] As Figures 1 - 5 shown, for a rock mass beam structure in this embodiment, the structure is the same as that in Embodiment 1, the difference is that: several prestressed anchor cables 13 are arranged through the beam structure 17. The ends of the prestressed anchor cables 13 are connected to the operation tunnel 12. The prestressed anchor cables 13 include straight sections and curved sections. The end of the straight section is the anchoring end 131, and the end of the curved section is the tensioning end 132. The projection of the anchoring end 131 on the vertical projection plane is higher than that of the tensioning end 132.

[0072] Preferably, the prestressed anchor cables 13 are made of steel strands, connecting two adjacent operation tunnels 12. In terms of shape, they include straight sections and curved sections. During tensioning, by applying a tensile force to the tensioning end 132 on the lower side, the tensile force is transmitted through the curved section and the straight section to the anchoring end 131 on the higher side in sequence, generating a downward stress on the beam structure 17. Through the prestress action, the beam structure 17 generates a downward deformation, realizing the active settlement function and counteracting the floor heave deformation.

[0073] Preferably, in some embodiments, several of the prestressed anchor cables 13 are arranged staggeredly along the extending direction of the operation tunnel 12. The staggered arrangement means that in any operation tunnel 12, the anchoring end 131 and the tensioning end 132 are arranged alternately at intervals along the extending direction of the operation tunnel 12, so as to realize the relatively balanced and uniform downward stress applied to the beam structure 17 under the action of multiple prestressed anchor cables 13.

[0074] Preferably, in some embodiments, the reinforcement structure and the prestressed anchor cables 13 are arranged alternately at intervals along the extending direction of the operation tunnel 12. Preferably, the reinforcement structure and the anchoring end 131 of the prestressed anchor cables 13 are at the same height.

[0075] Example 3

[0076] As Figures 1 - 5 shown, a rock mass beam structure in this embodiment has the same structure as that in Embodiment 1 or Embodiment 2, the difference is that: a plurality of drain holes 15 are arranged on the side wall of the operation tunnel 12, the drain holes 15 obliquely extend into the rock mass, a water channel 16 is arranged in the operation tunnel 12, and the water channel 16 is located below the drain holes 15.

[0077] Preferably, the drain hole 15 is a blind hole structure formed by drilling a hole on the side wall of the operation tunnel 12 far from the beam structure, which is used to drain the groundwater in the surrounding rock mass into the water channel 16 in the operation tunnel 12, reduce the surrounding groundwater level, and eliminate the floor heave deformation caused by the water pressure in the tunnel area.

[0078] Example 4

[0079] As Figures 1 - 5 shown, a rock mass beam structure in this embodiment has the same structure as that in Embodiment 1, Embodiment 2 or Embodiment 3, the difference is that: all the operation tunnels 12 are arranged in parallel on the same horizontal plane with the same elevation, the bottom surfaces of all the isolation grooves 11 maintain a unified elevation, and deformation adjustment holes, reinforcement structures and prestressed anchor cables 13 are transversely and relatively connected between adjacent operation tunnels 12.

[0080] A rock mass beam structure in this embodiment, the parallel operation tunnels 12 and the isolation grooves 11 can be isolated to form a cuboid rock mass beam structure, the structure is simpler, the construction feasibility is higher, and it can be applied to the rock mass where floor heave deformation has occurred, continuous floor heave deformation occurs or floor heave deformation may occur. According to the actual situation, the treatment measures between adjacent operation tunnels 12 can be adjusted to achieve different use effects, realize the induced deformation, resistance to deformation or active settlement of the rock mass and their combination, improve the use flexibility, and have good social and economic value.

[0081] Specifically, according to the actual situation, the structural characteristics such as the extension direction of the operation tunnel 12, the height difference between adjacent operation tunnels 12, the depth of the isolation groove 11, and the transverse connection structure between adjacent operation tunnels 12 can be adjusted to make the rock mass beam structure have different anti-floor heave effects and adapt to the use environment.

[0082] Example 5

[0083] As Figures 1 - 17 shown, this embodiment provides a method for resisting floor heave deformation of a rock mass beam structure, which combines a rock mass beam structure in Embodiments 1-4 at the same time. As Figure 6 shown, the rock mass beam structure is applied to the rock mass at the bottom of the subgrade project. As Figure 7 shown, the rock mass beam structure is applied to the soil mass below the embankment section.Figure 8 As shown, the rock mass beam structure is applied to the tunnel to achieve multi-functional suppression of the arching of the ballastless track during the operation of high-speed railways.

[0084] Preferably, taking the application of the rock mass beam structure to the section where the ballastless track arches during the operation of the tunnel as an example, the anti-floor heave deformation method is described as follows: The rock mass beam structure as described in Embodiment 1 is continuously or discontinuously arranged at the bottom of the tunnel 26. The rock mass beam structure is spaced from the bottom surface of the invert arch 21 of the tunnel in the vertical direction. A total of two operation galleries 12, left and right, are symmetrically arranged on both longitudinal sides at the bottom of the tunnel 26. The two operation galleries 12 are symmetrically arranged on both sides of the tunnel cross-section. The operation galleries 12 are in the same extending direction as the tunnel 26. The operation galleries 12 on both left and right sides and the isolation grooves 11 at their bottoms isolate the horizontal ground stress within this depth range and away from the tunnel 26 side, forming a beam structure 17. After the construction of the operation galleries 12 and the isolation grooves 11 is completed, the horizontal ground stress is isolated through the isolation grooves 11, so that the horizontal ground stress no longer acts on the beam structure 17. The beam structure 17 does not bear the horizontal load and will not undergo upward longitudinal bending deformation, which can play a role in isolating the floor heave deformation caused by the horizontal ground stress. At the same time, the operation galleries 12 and the isolation grooves 11 induce the original horizontal ground stress in the rock mass at the bottom of the tunnel 26 to be released in the direction of the operation galleries 12 and the isolation grooves 11, providing a space for the release of ground stress, alleviating the floor heave deformation caused by the ground stress, inducing the vertical floor heave deformation to transform into horizontal expansion deformation, reducing the amount of floor heave deformation of the tunnel, and realizing the induction of the floor heave deformation of the tunnel.

[0085] Specifically, after the construction of the structures of the operation galleries 12 and the isolation grooves 11 is completed, the reduction amount of the floor heave deformation = (horizontal ground stress σ / rock mass stiffness E under the tunnel) × lateral pressure coefficient λ × height of the beam structure, where the height of the beam structure 17 is equal to the height H1 of the operation gallery + the depth H2 of the isolation groove.

[0086] Specifically, the self-weight of the rock mass beam structure is determined by the height, width, and length of the rock mass beam structure. The self-weight of the rock mass beam structure resists the floor heave load below the rock mass beam structure. The height of the rock mass beam structure is determined by the sum of the heights of the isolation grooves 11 and the operation galleries 12 in the vertical projection plane. The width is determined by the spacing between the operation galleries 12. The length is determined by the length of the isolation grooves 11 along the longitudinal direction of the tunnel 26. By restricting the height, width, and length of the beam structure 17, the self-weight of the beam structure 17 is adjusted, and the stiffness of the beam structure 17 is increased to improve the ability of the rock mass beam structure to resist the floor heave load below.

[0087] Specifically, compared with the existing technical solutions for dealing with the arching of the ballastless track 23 in the tunnel 26 under the condition of high-speed rail operation, which affect the operation of high-speed rail, and even interrupt the operation, resulting in huge operation losses; in this embodiment, the treatment of the floor heave of the tunnel and the arching of the ballastless track 23 is carried out in the rock mass outside the tunnel, which does not affect the normal operation at all and has good social and economic value.

[0088] Specifically, compared with the four existing technical solutions such as adjusting the curvature of the tunnel invert 21 and increasing the thickness of the invert, this embodiment solves the problem that it is difficult to add measures once the engineering measures in the tunnel 26 are completed, realizes dynamic treatment, can continue to add engineering measures, has good flexibility, and can be implemented in stages according to the specific deformation situation.

[0089] Specifically, compared with the existing technical solutions of adjusting the curvature of the tunnel invert 21 and increasing the thickness of the invert, this embodiment makes full use of the self-weight and compressive strength of the rock mass, sets a tensioned steel cage and prestressed anchor cables 13 in the rock mass, greatly improves the overall stiffness of the tunnel bottom, and has stronger anti-deformation ability.

[0090] Specifically, compared with the existing technical solutions of using prestressed long bolts or anchor cables to anchor the rock mass at the bottom of the tunnel, this embodiment has high safety and there is no risk that the loosening and failure of the prestressed structure will threaten the operation safety of high-speed rail.

[0091] Specifically, compared with the existing technical solutions of setting deformation absorption and isolation measures, this embodiment forms active settlement by horizontally drilling holes at the top of the rock mass beam structure at the bottom of the tunnel 26, and theoretically has an infinite ability to adjust the floor heave deformation.

[0092] Specifically, compared with the technical solution of in-situ stress release, this embodiment does not require large cavity structures such as pressure relief holes to be set around the tunnel 26, will not cause the tunnel lining structure to be stressed due to in-situ stress adjustment, and guides the deformation in a directional manner at a position far from the tunnel through the isolation groove 11 in the rock mass, with strong controllability.

[0093] Preferably, as Figure 7 shown, when the rock mass beam structure is applied to the embankment section, the top of the operation tunnel 12 is set to penetrate the ground according to the actual situation, so that the operation tunnel 12 and the isolation groove 11 are combined to form a foundation pit structure, and a beam structure 17 is formed between adjacent foundation pit structures. The difference from the application to the tunnel or the subgrade cutting section is that there is no rock mass load on the top of the beam structure 17. By setting a number of anti-pull piles, the anti-pull piles vertically pass through the reinforced concrete structural slabs arranged on both longitudinal sides of the embankment to provide a downward pulling force for the beam structure 17 and resist the floor heave deformation below the beam structure 17.

[0094] Specifically, a protective pipe is provided for the part of the anti-pull pile located in the beam structure 17, and the bottom is anchored in the rock mass below the beam structure 17 after passing through the beam structure 17.

[0095] Example 6

[0096] As Figures 1 - 17 shown, for a method of resisting floor heave deformation of a rock mass beam structure in this embodiment, on the basis of Embodiment 5, by drilling deformation adjustment holes from the operation tunnel 12, the rock mass between the bottom of the tunnel invert 21 and the top of the rock mass beam structure is extracted, so that the rock mass at the bottom of the tunnel 26 undergoes active settlement under the action of the self-weight load of the tunnel structure.

[0097] Specifically, in some embodiments, by drilling holes perpendicular to the longitudinal direction of the tunnel 26 in the upper semi-circular area of the operation tunnel 12, the rock mass at the bottom of the tunnel is extracted to form deformation adjustment holes.

[0098] Preferably, the deformation adjustment holes are arranged at intervals along the extension direction of the operation tunnel 12.

[0099] Preferably, the deformation adjustment holes communicate with another adjacent operation tunnel 12, and the axis of the deformation adjustment hole is perpendicular to the extension direction of the operation tunnel 12.

[0100] Example 7

[0101] As Figures 1 - 17 shown, for a method of resisting floor heave deformation of a rock mass beam structure in this embodiment, on the basis of Embodiment 6, by drilling deformation adjustment holes in the rock mass beam structure and arranging a reinforcement structure in the deformation adjustment holes, the flexural stiffness of the rock mass beam structure is adjusted to resist the floor heave load below the rock mass beam structure.

[0102] Preferably, the reinforcement structure includes a steel pipe pile 14, and the steel pipe pile 14 includes a steel pipe and a steel reinforcement cage arranged inside the steel pipe, and is formed by pouring concrete.

[0103] Specifically, the diameter of the deformation adjustment hole formed by drilling in the rock mass beam structure is larger than the outer diameter of the steel pipe. While increasing the flexural stiffness of the beam structure, it can prevent excessive settlement and realize the control of the degree of active settlement.

[0104] Specifically, as Figure 17 shown, the amount of active settlement under this method is mainly controlled by several factors such as the drilling radius R1, the steel pipe radius R2, the distance Z from the center of the drilling hole to the tunnel structure, and the internal friction angle β of the rock mass. The maximum settlement amount S and the settlement range W of the tunnel structure at the drilling position can be calculated according to the Peck formula, and the spacing of the longitudinal drilling holes below the tunnel can be determined according to the settlement range W of a single hole.

[0105] Preferably, for the sections where floor heave deformation has occurred, this method can be used to restore the original elevation of the ballastless track; for the sections where floor heave deformation will continue to occur in the future, this method can be used for multiple active settlement adjustments of the ballastless track elevation; for the sections where floor heave deformation may occur, this method can be used as a standby treatment measure.

[0106] Example 8

[0107] As Figures 1 - 17 shown, a method for resisting floor heave deformation of a rock mass beam structure in this embodiment, based on Embodiment 6 or Embodiment 7, by arranging prestressed anchor cables 13 in the rock mass beam structure to connect two adjacent working headings 12, adjusting the flexural stiffness of the rock mass beam structure, resisting the floor heave load under the rock mass beam structure. At the same time, prestress can be applied to the prestressed anchor cables 13 when necessary to carry out active settlement under the action of prestress.

[0108] A method for resisting floor heave deformation of a rock mass beam structure in this embodiment arranges prestressed anchor cables 13 in the rock mass beam structure through two working headings 12. Using the prestressed anchor cables 13 as prestressed reinforcement bars, the flexural stiffness of the rock mass beam structure is improved to resist the floor heave load under the rock mass beam structure. At the same time, by tensioning the anchor cables to apply prestress, the camber (the direction is downward, opposite to the direction of floor heave deformation) of the rock mass beam structure is formed by the action of prestress to achieve active settlement control.

[0109] Specifically, the active settlement amount under this method is mainly controlled by several factors such as the magnitude of prestress N, the span of the rock mass beam (2×L1 + L2), the sag f at the mid-span position of the prestressed steel bars, and the flexural stiffness EI of the rock mass beam. Among them, L1 is the net distance between the unilateral working heading and the tunnel structure, and L2 is the maximum width of the tunnel structure.

[0110] Specifically, under the action of prestress, the maximum settlement amount S of the tunnel 26 structure can be calculated according to the camber formula of the post-tensioned prestressed simply supported beam.

[0111] Preferably, for the section where floor heave deformation continuously occurs in the future, if the floor heave deformation intensifies, the floor heave deformation can be directly controlled by quickly applying prestress. Using this method to improve the flexural stiffness of the rock mass beam structure can achieve a better and faster rectification effect.

[0112] Example 9

[0113] As Figures 1 - 17 shown, a method for resisting floor heave deformation of a rock mass beam structure in this embodiment, based on any one of Embodiments 7 - 8, by drilling drainage holes 15 from the working heading 12 to lower the groundwater level in the tunnel 26 area, and discharging the water from the working heading 12 and the auxiliary heading outside the tunnel 26 rock mass to eliminate the floor heave deformation under the action of water pressure.

[0114] A method for resisting floor heave deformation of a rock mass beam structure in this embodiment. The operation tunnel 12 functions as a water collection corridor. By drilling holes at the bottom of the tunnel 26 and on the side walls of the operation tunnel 12, the groundwater level in the area of the tunnel 26 is lowered to the bottom of the operation tunnel 12, and the groundwater is discharged through an auxiliary tunnel externally connected to the operation tunnel 12, achieving the elimination of floor heave deformation caused by water pressure.

[0115] Embodiment 10

[0116] As Figures 1 - 17 shown, a method for resisting floor heave deformation of a rock mass beam structure in this embodiment, in combination with Embodiments 5 - 9, realizes the suppression of the arching of the ballastless track 23 in the tunnel 26 with multiple functions.

[0117] Specifically, first, by setting isolation grooves 11 with a certain depth on both sides of the bottom of the tunnel 26, the horizontal ground stress within this depth range is isolated, eliminating its effect on the rock mass at the bottom of the tunnel; the self-weight of the rock mass between the isolation grooves 11 is utilized to resist part of the deformation load at the bottom of the rock mass; and a free face for the deformation of the rock mass at the tunnel bottom is provided through the isolation grooves 11. By releasing the lateral constraints on both sides of the rock mass at the bottom of the tunnel 26, the deformation of the rock mass at the bottom of the tunnel 26 is guided to develop laterally, reducing the upward vertical development; then, the rock mass at the bottom of the tunnel 26 is transformed into a beam structure 17 that can resist deformation by setting a transverse reinforcement structure and prestressed anchor cables 13, actively bearing the bottom deformation load; and, through large-diameter drilling in the operation tunnels 12 on both sides, active settlement is implemented on the sections where the ballastless track 23 has arched, using the active settlement to counteract the floor heave deformation, achieving the active guidance and control of the deformation of the bottom structure of the tunnel 26; at the same time, the operation tunnels 12 on both sides of the tunnel 26 can also play the role of discharging groundwater, eliminating the buoyancy caused by groundwater.

[0118] Preferably, in the case of swelling rock mass, the operation tunnels 12 on both sides can also provide an operation space for replacing the rock mass at the base of the tunnel 26, and can achieve good results in dealing with the floor heave deformation caused by the swelling rock mass.

[0119] A method for resisting floor heave deformation of a rock mass beam structure in this embodiment is based on the rectification of the arching of the ballastless track 23 in the tunnel 26 caused by ground stress reasons. The operation tunnels 12 on both sides formed below the tunnel 26 can fully eliminate the arching of the ballastless track 23 caused by groundwater pressure, and can also use the operation tunnels 12 to further drill holes horizontally to replace the rock mass, eliminating the arching of the ballastless track 23 in the tunnel 26 caused by the expansibility of the rock mass. It belongs to a comprehensive rectification scheme for the floor heave deformation of the tunnel 26 and has good adaptability to complex geological conditions.

[0120] Embodiment 11

[0121] As Figures 1 - 17 shown, a construction method for a rock mass beam structure to resist tunnel floor heave deformation includes the following steps:

[0122] Step 1: Select an auxiliary adit entrance outside the mountain body where the tunnel 26 is located, construct the auxiliary adit to the designed position of the working adit 12, and excavate the working adit 12.

[0123] Step 2: Excavate an isolation groove 11 at the midline of the bottom of the working adit 12. The isolation groove 11 is excavated by the method of drilling with slurry support. After drilling, remove the slurry support and fill it with a flexible medium.

[0124] Step 3: Drill holes into the rock mass in the working adit 12 to form deformation adjustment holes connecting adjacent working adits 12.

[0125] In Step 1, the settlement deformation amount of the tunnel 26 caused by the excavation of the working adit 12 is S1; in Step 2, the settlement deformation amount of the tunnel 26 caused by the excavation of the isolation groove 11 is S2; in Step 3, the settlement deformation amount of the tunnel 26 caused by the formation of the deformation adjustment holes is S3.

[0126] A construction method for a rock mass beam structure to resist the bottom heave deformation of a tunnel in this embodiment causes the tunnel to have settlement deformation through the construction process of the rock mass beam structure. The total settlement deformation amount is the sum of the settlement deformation amounts at each stage of the construction process, enabling the rock mass beam structure to not only have the function of resisting the bottom heave deformation of the tunnel in terms of structure, but also have the functions of resisting and correcting the bottom heave deformation of the tunnel during the construction process.

[0127] Preferably, for a construction method for a rock mass beam structure to resist the bottom heave deformation of a tunnel in this embodiment, when it is applied to a tunnel section where bottom heave deformation has already occurred, with the already occurred bottom heave deformation amount D1 and the predicted subsequent bottom heave deformation amount D2 of the tunnel, in Step 1, the auxiliary adit is constructed to the lower end of the bottom heave section of the tunnel 26, and then the working adit 12 is constructed. After construction, if S1 + S2 + S3 ≥ D1, the already occurred bottom heave deformation of the tunnel can be eliminated, and the ballastless track 23 can be restored to its original elevation.

[0128] Preferably, for a construction method for a rock mass beam structure in this embodiment, when it is applied to a section where bottom heave deformation will continue to occur in the future, the number of times of Step 3 can be adjusted to achieve the elevation control of the ballastless track 23.

[0129] Preferably, for a construction method for a rock mass beam structure to resist the bottom heave deformation of a tunnel in this embodiment, when it is applied to a section where bottom heave deformation may occur, Step 3 is used as a standby rectification measure and is selected according to the actual situation.

[0130] The present embodiment provides a construction method for a rock beam structure to resist tunnel floor drum deformation, wherein the rock beam structure is formed outside the tunnel 26, and the normal operation of the tunnel 26 is ensured while the floor drum deformation of the tunnel 26 is effectively guided and controlled. This is a comprehensive solution for the treatment of the floor drum deformation of the tunnel 26, and has good adaptability to complex geological conditions. Treatment measures can be added and adjusted according to the actual use of the tunnel 26 and the floor drum deformation conditions, and has high flexibility and great social and economic value.

[0131] Preferably, since the construction of the isolation trench 11 will induce deformation of the rock mass below and cause settlement of the tunnel 26, during the construction process, the isolation trenches 11 on both sides of the tunnel 26 are symmetrically constructed while closely monitoring the elevation changes of the ballastless track 23.

[0132] Taking the construction of a rock beam structure under a tunnel as an example, working tunnels 12 are excavated on the left and right sides of tunnel 26 respectively. The width of working tunnel 12 is 5m and the height is 6m. The edge of working tunnel 12 is 15m away from the edge of the tunnel structure (i.e. L1=15m), and the top of working tunnel 12 is 3m away from the top of tunnel invert 21. Working tunnel 12 adopts 20cm thick shotcrete, φ8mm steel mesh and φ22mm mortar anchor to form anchor mesh spraying support. An isolation groove with a width of 0.6m and a depth of 10m is set at the center line of the bottom of working tunnel 12. Isolation groove 11 is drilled with mud wall protection. After drilling construction, the mud is removed and filled with foam material to form a rock beam structure, forming a remediation measure for induced deformation.

[0133] Preferably, in step three, a deformation adjustment hole with a diameter of φ180 mm is drilled in the rock mass, and the diameter of the drilled hole is calculated according to the amount of active settlement to form a remediation measure for active settlement.

[0134] Example 12

[0135] like Figures 1 - 17 As shown, a construction method for a rock beam structure to resist tunnel floor drum deformation in this embodiment, based on embodiment 11, also includes step four: setting a reinforcement structure in the deformation adjustment hole formed in step three, after the reinforcement structure is set, the rock beam structure can resist the floor drum deformation of S4, if S4>D2, the later floor drum deformation can be offset.

[0136] Preferably, a deformation adjustment hole is formed by drilling in step three, and after the bottom drum deformation that has occurred is eliminated, a steel pipe pile 14 with a slightly smaller diameter is inserted into the deformation adjustment hole, a steel cage is installed in the steel pipe of the steel pipe pile 14 and concrete is poured to seal it to prevent excessive settlement of the rock beam structure.

[0137] Taking the construction of a rock beam structure under a certain tunnel as an example, in Step 3, deformation adjustment holes with a diameter of φ180mm are drilled in the rock mass. The deformation adjustment holes are arranged longitudinally along the tunnel 26 at intervals of 100cm. In Step 4, steel pipes with a diameter of φ159mm are inserted into the deformation adjustment holes. The steel pipes are segmented transversely every 2m. The steel pipes are internally provided with a steel reinforcement cage composed of 4 φ22mm steel bars. After the active settlement is completed, the gaps between the deformation adjustment holes and the steel pipes are filled with grouted cement slurry to improve the flexural stiffness of the rock beam structure and form a rectification measure to resist deformation.

[0138] Example 13

[0139] As Figures 1 - 17 shown, a construction method for a rock beam structure to resist floor heave deformation of a tunnel in this embodiment, on the basis of Example 12, further includes Step 5: If S4 ≤ D2, drill prestressed anchor cable installation holes in the operation tunnel, install the prestressed anchor cables 13 and perform prestress tensioning to form a rectification measure for active settlement under the action of prestress.

[0140] Taking the construction of a rock beam structure under a certain tunnel as an example, a horizontally drilled hole with a bent end at the other end is constructed from the top end of the operation tunnel 12 to the bottom end of the adjacent operation tunnel 12. The drilling size is φ108mm to form a prestressed anchor cable 13 installation hole and install the prestressed anchor cable 13. The vector height of the anchor cable shape is 3.5m. On the higher side of the installation hole, that is, the anchoring end 131, an anchoring agent is poured. After the anchoring agent is completely solidified and reaches the design strength, on the lower side of the installation hole, that is, the tensioning end 132, prestress is applied to the anchor cable 13. During the construction period, the settlement deformation amount S5 of the tunnel caused by the tensioning of the prestressed anchor cable 13 is measured in real time.

[0141] Preferably, in some embodiments, along the extension direction of the operation tunnel 12, every two anchor cables form a group. That is, the anchoring end 131 to the tensioning end 132 of one anchor cable is arranged from left to right, and the anchoring end 131 to the tensioning end 132 of the adjacent other anchor cable is arranged from right to left. The distance between adjacent anchor cables is 30cm. The magnitude of the prestress tension applied to the anchor cables is calculated according to the required active settlement amount. In addition, the prestress loss is regularly checked after the prestress is applied, and supplementary tensioning is carried out if necessary.

[0142] Preferably, in some embodiments, the floor heave disease of the tunnel 26 is mainly rectified through Step 2 and Step 3. After the drilling depth in Step 2 exceeds a certain depth, Step 3 is started, and Step 4 is carried out in cooperation with Step 3. Step 3 can be used multiple times according to the actual situation. If (the current floor heave deformation amount D1 + the predicted floor heave deformation amount D2) > S1 + S2 + S3 + S4, then Step 5 is carried out, and a tensile force is applied to the prestressed anchor cable 13 until S4 + S5 > D2, and the application of the tensile force to the prestressed anchor cable 13 is stopped.

[0143] Preferably, in step five, the prestressed anchor cable 13 can be tensioned multiple times according to the actual situation.

[0144] Embodiment 14

[0145] As Figures 1 - 17 shown, a construction method for a rock mass beam structure to resist the bottom heave deformation of a tunnel in this embodiment, on the basis of any one of Embodiments 11-13, further includes constructing drainage holes 15 on the side wall of the operation tunnel 12 away from the tunnel, and pouring a drainage ditch 16 below the drainage holes 15 in the operation tunnel 12, and the step of eliminating the groundwater pressure, forming a rectification measure for eliminating the bottom heave deformation caused by the water pressure.

[0146] Taking the construction of a rock mass beam structure under a certain tunnel as an example, a certain number of φ42mm drainage holes 15 are arranged on the side wall of the operation tunnel 12 away from the tunnel. Preferably, 3 rows of drainage holes 15 are set. The longitudinal spacing of the drainage holes 15 along the tunnel 26 is 10m, the spacing between adjacent rows of drainage holes 15 is 1m, the hole depth is 4m, and a drainage ditch 16 with a width of 40cm and a height of 30cm is arranged below the drainage holes 15.

[0147] Specifically, the size of the drainage ditch 16 can be adjusted according to the actual water volume.

[0148] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A rock mass beam structure, characterized in that, it includes a number of working tunnels (12) arranged in a strip shape. An isolation groove (11) is formed along the shape of the bottom of the working tunnel (12). The isolation groove (11) includes a vertically arranged channel, and the channel is filled with a flexible medium. The working tunnel (12) and the isolation groove (11) serve as boundaries to separate and form a beam structure (17). The beam structure (17) is provided with deformation adjustment holes and / or reinforcement structures and / or prestressed anchor cables (13). The deformation adjustment holes, the reinforcement structures and the prestressed anchor cables (13) are connected to the working tunnel (12). The deformation adjustment holes are formed by drilling from the working tunnel into the rock mass. The reinforcement structure includes a number of steel pipe piles (14) horizontally penetrating through the beam structure (17); the prestressed anchor cable (13) includes a straight section and a curved section. The end of the straight section is an anchoring end (131), and the end of the curved section is a tensioning end (132). The projection of the anchoring end (131) on the vertical projection plane is higher than that of the tensioning end (132). A number of the prestressed anchor cables (13) are arranged alternately along the extension direction of the working tunnel (12).

2. The rock mass beam structure according to claim 1, characterized in that, the reinforcement structure and the prestressed anchor cable (13) are arranged at intervals and alternately along the extension direction of the working tunnel (12).

3. The rock mass beam structure according to claim 1, characterized in that, a number of drainage holes (15) are arranged on the side wall of the working tunnel (12). The drainage holes (15) are inclined. A water channel (16) is arranged in the working tunnel (12), and the water channel (16) is located below the drainage holes (15).

4. The rock mass beam structure according to claim 1, characterized in that, all the working tunnels (12) are arranged at the same or similar elevations, the bottom surfaces of all the isolation grooves (11) are at the same elevation, and the deformation adjustment holes, the reinforcement structures and the prestressed anchor cables (13) are connected relatively between adjacent working tunnels (12).

5. The rock mass beam structure according to claim 1, characterized in that, it is applied to the rock mass at the bottom of a tunnel (26) or a subgrade (27). Two of the working tunnels (12) are distributed on both longitudinal sides of the tunnel or the subgrade. The working tunnel (12) is provided with bolt-shotcrete support. The working tunnel (12) is connected to the external space of the rock mass through an auxiliary tunnel. The isolation groove (11) is arranged at the midline position of the bottom of the working tunnel (12).

6. The rock mass beam structure according to claim 1, characterized in that, it is applied to an embankment section. Two of the working tunnels (12) are distributed on both longitudinal sides of the embankment. The top of the working tunnel (12) penetrates the ground surface. The working tunnel (12) and the isolation groove (11) are combined to form a foundation pit structure, and the beam structure (17) is formed between adjacent foundation pit structures; On the top surface of the beam structure (17), reinforced concrete structural slabs are respectively arranged on both longitudinal sides of the embankment (28). A number of uplift piles (19) vertically pass through the structural slabs and are anchored in the bedrock at the bottom of the beam structure (17). The structural slabs are arranged continuously or discontinuously along the extension direction of the foundation pit structure, and a number of the uplift piles (19) are arranged along the extension direction of the foundation pit structure.

7. A construction method for a rock mass beam structure to resist the bottom heave deformation of a tunnel, characterized in that, a rock mass beam structure as claimed in any one of claims 1 - 6 is arranged continuously or discontinuously in the rock mass at the bottom of the tunnel (26). The rock mass beam structure is arranged at an interval from the bottom surface of the tunnel invert (21) in the vertical direction. Two operation galleries (12) are symmetrically arranged on both sides of the cross-section of the tunnel (26). The operation galleries (12) are the same as or similar to the extension direction of the tunnel (26), and the method comprises the following steps: Step 1: Select an auxiliary gallery opening outside the mountain where the tunnel (26) is located, construct the auxiliary gallery to the designed position of the operation gallery (12), and excavate the operation gallery (12); Step 2: Excavate an isolation groove (11) at the bottom center line of the operation gallery (12). The isolation groove (11) is excavated by the method of slurry-supported drilling. After the drilling is completed, the slurry support is removed, and a flexible medium is filled; Step 3: Drill holes in the rock mass from the operation gallery (12) to form deformation adjustment holes connecting adjacent two operation galleries (12); Step 4: Arrange a reinforcement structure in the deformation adjustment holes formed in Step 3; In Step 1, the settlement deformation amount of the tunnel (26) caused by the excavation of the operation gallery (12) is S1; in Step 2, the settlement deformation amount of the tunnel (26) caused by the excavation of the isolation groove (11) is S2; in Step 3, the settlement deformation amount of the tunnel (26) caused by the formation of the deformation adjustment holes is S3; in Step 4, the rock mass beam structure can resist the bottom heave deformation amount of S4 after the reinforcement structure is arranged.

8. A construction method for a rock mass beam structure to resist the bottom heave deformation of a tunnel as claimed in claim 7, characterized in that, when it is applied to the section of the tunnel (26) where bottom heave deformation has occurred, the bottom heave deformation amount D1 that has occurred in the tunnel and the predicted bottom heave deformation amount D2 in the later stage. The designed starting position of the operation gallery (12) is the end with a lower elevation in the bottom heave section of the tunnel (26); if S1 + S2 + S3 ≥ D1, the bottom heave deformation that has occurred in the tunnel (26) can be eliminated, and the ballastless track (23) can be restored to the original elevation; if S4 > D2, the offset of the bottom heave deformation in the later stage can be realized; if S4 ≤ D2, drill prestressed anchor cable installation holes in the operation gallery (12), install prestressed anchor cables (13) and carry out prestress tensioning. The settlement deformation amount of the tunnel (26) caused by the tensioning of the prestressed anchor cables (13) is S5; if S1 + S2 + S3 + S4 < (D1 + D2), apply a tensile force to the prestressed anchor cables (13). If S4 + S5 > D2, stop applying the tensile force to the prestressed anchor cables (13); when it is applied to the section where bottom heave deformation will continuously occur in the future, adjust the number of times of Step 3 and Step 4, and the elevation control of the ballastless track (23) can be realized; When applied to the section where floor heave deformation may occur, Step 3 and Step 4 are used as alternative treatment measures.

9. A construction method for a rock mass beam structure to resist tunnel floor heave deformation according to claim 8, characterized in that, it further includes the steps of constructing a drainage hole (15) on the side wall of the working tunnel (12) far from the tunnel (26), and pouring a drainage ditch (16) below the drainage hole (15) in the working tunnel (12) to eliminate the groundwater pressure in the tunnel (26) area.

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