A method for drilling holes for rapid rock breaking and tunneling in a hard rock tunnel

Abstract

The application is a kind of hard rock roadway rapid rock breaking and tunneling drilling method, belonging to the field of mine roadway tunneling; solves the problem of low efficiency of existing hard rock roadway tunneling; technical scheme: including the following steps: step S1, dividing the hard rock roadway section into a center operation area and several expansion tunneling operation areas, step S2, arranging a first crack zone in the center operation area and a second crack zone distributed around the first crack zone, drilling a plurality of second main crack holes and a plurality of second auxiliary drilling holes in the second crack zone, then using a rock breaking device to simultaneously crack the plurality of first crack holes of the first crack zone, and then cracking the second main crack holes in the second crack zone in order from top to bottom and from center to periphery, step S3, arranging a fourth crack zone in each of the plurality of expansion tunneling operation areas, and then breaking the expansion tunneling operation areas in order from top to bottom and from left to right; the application is applied to hard rock roadway tunneling.

Description

Technical Field

[0001] The invention provides a drilling method for fast rock breaking and excavation in a hard rock tunnel, belonging to the technical field of mine tunnel excavation. Background Art

[0002] In recent years, with the continuous advancement of coal mining, the resources of shallow, near-horizontal and gently inclined coal seams that are easy to mine in the mining area have become increasingly depleted. Mining operations have gradually shifted to deep coal seams, and the problem of slow rock tunnel excavation speed has become increasingly prominent. In actual construction, it was found that even if the rock formation is stable, due to its hard texture, the excavation efficiency is always difficult to improve. The excavation efficiency directly restricts the progress of mine development, which in turn affects the overall mining efficiency. This problem is mainly manifested in two aspects: First, the rock hardness of some all-rock tunnels is extremely high. The all-rock tunnel boring machines currently on the market are mostly suitable for medium and low hardness rocks. In actual operations, it is often difficult to achieve theoretical performance indicators; second, the comprehensive excavation equipment forms the tunnel contour by cutting and rubbing the rock wall, and gradually advances forward. When the comprehensive excavation equipment faces high-hardness and high-wear-resistant rock formations, the equipment's excavation efficiency drops significantly, the wear of the cutting components increases, and the loss of the entire machine increases significantly.

[0003] Currently, the technical approaches to increasing hard rock tunneling speeds primarily focus on equipment enhancement and pre-splitting rock breaking. Common measures for equipment enhancement include improving the material and structure of cutter teeth and adopting percussive tunneling techniques. Pre-splitting rock breaking methods include hydraulic fracturing, microwave irradiation, and blasting. However, due to factors such as construction costs, limited working space, and safety regulations, the widespread application of these technologies in some coal mines faces numerous obstacles. Summary of the Invention

[0004] In order to solve the technical problem of low excavation efficiency in existing hard rock tunnels, the present invention proposes a drilling method for rapid rock breaking and excavation in hard rock tunnels.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is: a drilling method for rapid rock breaking and excavation in a hard rock tunnel, comprising the following steps:

[0006] Step S1: Divide the free section of the hard rock roadway into several operating areas, namely a central operating area and multiple expanded excavation operating areas, wherein the multiple expanded excavation operating areas are distributed around the central operating area;

[0007] Step S2: Arrange a first fracturing zone of a regular polygon and second fracturing zones distributed around the first fracturing zone in the central operating area, drill a first main fracturing hole at the center point and each vertex in the first fracturing zone, and evenly open a plurality of first auxiliary drilling holes in the first fracturing zone; drill a plurality of second main fracturing holes and a plurality of second auxiliary drilling holes in the second fracturing zone, the plurality of second main fracturing holes are distributed in an array in the geometric regularity of a regular triangle, and the plurality of second auxiliary drilling holes are distributed on a preset fracturing extension path of the second fracturing zone and at the edge of the second fracturing zone; after arranging the first main fracturing holes and the second main fracturing holes, use rock breaking equipment to simultaneously fracture the plurality of first main fracturing holes in the first fracturing zone, and then fracture the second main fracturing holes in the second fracturing zone in sequence from top to bottom and from the center to the surrounding areas;

[0008] Step S3: arrange a fourth fracturing zone in each of the multiple expanded excavation work areas, arrange a third fracturing zone in the shape of a regular polygon at the center of at least two fourth fracturing zones, drill a third main fracturing hole at the center point and each vertex of the third fracturing zone, and evenly open multiple third auxiliary drilling holes in the third fracturing zone; open multiple fourth main fracturing holes distributed in a regular array of regular triangles in the fourth fracturing zone, and evenly open multiple fourth auxiliary drilling holes at the edge of the fourth fracturing zone; after arranging the third auxiliary drilling holes and the fourth auxiliary drilling holes, break up multiple expanded excavation work areas in sequence from top to bottom and from left to right.

[0009] Furthermore, the first bursting zone is a regular pentagon, and five first auxiliary drilling holes are opened. The five first auxiliary drilling holes are distributed in five regular triangle areas formed by connecting the center point of the first bursting zone and each vertex.

[0010] Furthermore, when breaking the second bursting zone, the equilateral triangle area directly below the first bursting zone is first bursted, and the second main bursting holes located directly below the equilateral triangle area are gradually burst downward until the lower edge of the second bursting zone. Then, all the second main bursting holes at the lower edge of the second bursting zone are linearly burst in a continuous manner, and then the remaining second main bursting holes are burst upward layer by layer in a continuous manner.

[0011] Furthermore, in step S2, when the second main bursting holes are arranged at a preset interval, if the second main bursting holes to be arranged will exceed the edge of the second bursting zone, a second auxiliary drilling hole is arranged at the edge of the second bursting zone so that the length of the crack of the second auxiliary drilling hole does not exceed the second bursting zone.

[0012] Furthermore, when the excavation operation area is crushed and expanded in step S3, the third expansion zone is crushed first, and then the fourth main expansion hole in the triangular area near the lower part of the fourth expansion zone is crushed, and then the fourth main expansion hole is crushed in the direction of the geometric center line of the free section of the hard rock tunnel in a continuous and uninterrupted manner, and then the fourth main expansion hole is crushed layer by layer upward, and finally the fourth main expansion hole at the edge of the fourth expansion zone is crushed along the contour of the fourth expansion zone, forming a surrounding crushing method.

[0013] Furthermore, two third expansion and fracture zones are arranged in step S3, and the two third expansion and fracture zones are respectively located at the central concentrated crushing points of the corresponding two fourth expansion and fracture zones. The two expanded excavation operation areas corresponding to the two fourth expansion and fracture zones are both located above the central operation area, and the remaining expanded excavation operation areas are located below the central operation area and no third expansion and fracture zones are arranged.

[0014] Furthermore, the third bursting zone is a regular pentagon or a regular triangle.

[0015] Furthermore, in step S3, before crushing the next operating area, the distance between the two main expansion holes arranged in the next operating area is dynamically adjusted.

[0016] Furthermore, high-pressure water is injected into the first fracturing zone to assist the rock breaking equipment in breaking the rock mass in the first fracturing zone.

[0017] Furthermore, the first expansion and fracturing zone is provided with a plurality of water injection holes, and the second expansion and fracturing zone is provided with a plurality of drainage holes, and the water injection holes and the drainage holes cooperate with each other.

[0018] The present invention has the following beneficial effects compared to the prior art:

[0019] 1. The present invention divides the free section of a hard rock roadway into a central operating area and several expanded excavation operating areas, with the multiple expanded excavation operating areas distributed around the central operating area. The method of drilling first and then fracturing is adopted to gradually and layer by layer crush the rock mass of the free section of the hard rock roadway in the order of top to bottom and from the center to the surrounding areas. This method can achieve efficient crushing of rock mass with a surrounding rock strength coefficient f ≥ 8.

[0020] 2. The drilling method for rapid rock breaking and excavation in a hard rock tunnel of the present invention simultaneously fractures all first expansion holes in the first expansion fracture zone when crushing the rock mass in the central working area. When crushing multiple expanded excavation working areas, they are crushed one by one in a sequence from top to bottom and from the center to the surrounding areas. This facilitates management and construction, effectively preventing the upper working area from losing its support force after the lower working area is crushed, thereby exacerbating dust diffusion. It also prevents the upper working area from collapsing after the lower working area is crushed, thereby increasing the excavation workload in the lower working area, thereby improving excavation efficiency.

[0021] 3. The present invention can effectively increase the rock mass expansion and crack development rate and the development of cracks by opening auxiliary drilling holes in the working area, and can effectively guide the development direction of cracks after the main expansion holes are expanded, thereby promoting the development of rock mass cracks in a preset direction, so that the hard rock tunnel can achieve an ideal crushing state;

[0022] 4. The present invention adopts the form of injecting high-pressure water into the first expansion and fracturing zone to assist the rock breaking equipment in breaking the rock mass in the first expansion and fracturing zone, which can effectively reduce the tensile strength of the rock mass and further improve the crushing efficiency of the first expansion and fracturing zone. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The present invention will be further described below with reference to the accompanying drawings:

[0024] Figure 1 This is a distribution diagram of hole positions in each working area when the surrounding rock strength coefficient f of the arched free section of the hard rock tunnel of the present invention is within the range of 10 to 12;

[0025] Figure 2 This is a distribution diagram of hole positions in each working area when the surrounding rock strength coefficient f of the arched free section of the hard rock tunnel of the present invention is within the range of 8 to 10;

[0026] Figure 3 The pore distribution of the first bursting zone of the present invention is Figure 1 ;

[0027] Figure 4 This is a hole position distribution diagram when the third bursting zone of the present invention is an equilateral triangle;

[0028] Figure 5 Schematic diagram of the positional relationship between the first main fracturing hole and the first auxiliary drilling hole in the first fracturing zone of the present invention Figure 1 ;

[0029] Figure 6 The pore distribution of the first bursting zone of the present invention is Figure 2 ;

[0030] Figure 7 Schematic diagram of the positional relationship between the first main fracturing hole and the first auxiliary drilling hole in the first fracturing zone of the present invention Figure 2 ;

[0031] Figure 8 This is a schematic diagram of the free cross-section structure of the hard rock tunnel behind the working area of ​​the crushing center of the present invention;

[0032] Figure 9 This is a schematic diagram of the free cross-section structure of a hard rock tunnel after the crushing center working area and an expanded excavation operation area of ​​the present invention;

[0033] Figure 10 This is a schematic diagram of the free cross-section structure of the hard rock tunnel after the crushing center working area and two expanded excavation operation areas of the present invention;

[0034] Figure 11 A schematic diagram of a free cross section structure of a hard rock roadway after a breaking center work area and three enlarged excavation operation areas of the present application;

[0035] Figure 12 A work flow chart of the present application;

[0036] In the figure: 1 is a regional division line, 2 is a first expansion cracking zone, 3 is a first main expansion cracking hole, 4 is a second expansion cracking zone, 5 is a second main expansion cracking hole, 6 is a second auxiliary drilling hole, 7 is a third expansion cracking zone, 8 is a third main expansion cracking hole, 9 is a third auxiliary drilling hole, 10 is a fourth expansion cracking zone, 11 is a fourth main expansion cracking hole, 12 is a fourth auxiliary drilling hole, 13 is a hard rock roadway, 14 is a water injection hole, 15 is a drainage hole, 16 is a center operation area, 17 is an enlarged excavation operation area, 18 is a fissure, and 19 is a first auxiliary drilling hole. DETAILED DESCRIPTION

[0037] In the description of the present application, it should be understood that the relative or positional relationship indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is a relative or positional relationship for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined with "first", "second", etc. can explicitly or implicitly include one or more of the features. In the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0038] In the description of the present application, it should be noted that, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be a fixed connection, or a detachable connection, or an integral connection; it can be a mechanical connection, or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood through specific circumstances.

[0039] First, the meanings of some terms appearing in the present technical solution are clarified:

[0040] Over-break and under-break: It is a technical term used in engineering. It takes the designed excavation contour line as the benchmark. The part of the actual excavated section outside the baseline is called over-break, and the part inside the baseline is called under-break.

[0041] Irregular lithology: a geological term that refers to the phenomenon that the composition, structure or spatial distribution of rocks show heterogeneous, discontinuous or sudden changes.

[0042] like Figures 1 to 12 As shown, the present invention provides a drilling method for rapid rock breaking and excavation in a hard rock tunnel, comprising the following steps:

[0043] Step S1: Divide the free section of the hard rock tunnel 13 into several working areas, namely a central working area 16 and a plurality of expanded excavation working areas 17, wherein the plurality of expanded excavation working areas 17 are distributed around the central working area 16. Figure 1 The area distribution is divided by the dividing line 1.

[0044] Currently, the free cross-section of the hard rock tunnel 13 is mostly arched or trapezoidal. Based on the shape of the free cross-section, the free cross-section is divided into five areas according to the different stress distribution conditions. Specifically, the free cross-section of the hard rock tunnel 13 is divided into a rectangular central operating area 16 and four irregular expanded excavation operating areas 17 distributed around the central operating area 16. The four expanded excavation operating areas 17 are the first expanded excavation area, the second expanded excavation area, the third expanded excavation area, and the fourth expanded excavation area. The first expanded excavation area and the second expanded excavation area are located above the central operating area 16, and the third expanded excavation area and the fourth expanded excavation area are located below the central operating area 16. Among them, the area of ​​the central operating area 16 should meet the following requirements:

[0045]

[0046] Wherein, s is the area of ​​the free section of the hard rock tunnel 13, and s1 is the area of ​​the central working area 16.

[0047] Step S2: Arrange a first, regular polygonal bursting zone 2 and second bursting zones 4 distributed around the first bursting zone 2 in the central operating area 16. The first bursting zone 2 and the second bursting zone 4 cover the entire central operating area 16, i.e., the second bursting zone 4 is the area of ​​the central operating area 16 excluding the first bursting zone 2, and the first bursting zone 2 is a stress concentration zone. First main bursting holes 3 are drilled at the center point and each vertex of the first bursting zone 2, and multiple first auxiliary drilling holes 19 are evenly distributed within the first bursting zone 2. Multiple second main bursting holes 5 and multiple second auxiliary drilling holes 6 are drilled within the second bursting zone 4. The multiple second main bursting holes 5 are neatly arranged according to the geometric rules of a regular triangle to form an orderly array structure. Multiple second auxiliary drilling holes 6 are distributed along the preset bursting expansion path of the second bursting zone 4 and at the edges of the second bursting zone 4. After the first main fracturing holes 3 and the second main fracturing holes 5 are laid out, rock breaking equipment is used to simultaneously fracture multiple first main fracturing holes 3 in the first fracturing zone 2, and then rock breaking equipment is used to sequentially fracture the second main fracturing holes 5 in the second fracturing zone 4 in order from top to bottom and from the center to the surrounding areas.

[0048] Before operating step S2, you need to perform the following operations:

[0049] 1. A model of the hard rock roadway 13 to be crushed is established based on various parameters of the hard rock roadway 13, and the rock mass fracture length value is obtained through simulation experiments. The rock mass fracture length value includes the rock mass fracture length value during single-hole crushing and the rock mass fracture length value of each operating area after completing the crushing process of the previous operating area.

[0050] Specifically, after completing rock sampling on site of the hard rock tunnel 13 to be crushed, the samples were brought back to the laboratory, and uniaxial compression (UCS) tests and Brazilian splitting tests were carried out respectively to obtain the key parameters of the rock tunnel, including tensile strength, compressive strength, Poisson's ratio, elastic modulus and surrounding rock strength coefficient. Based on the key parameters obtained above, a simulation software was used to construct a model of the hard rock tunnel 13 to simulate the crushing operation of the hard rock tunnel 13, and obtain the stress distribution of the hard rock tunnel 13 before crushing. In the excavation project, after each operating area was crushed, the simulated stress distribution, simulated tensile strength, simulated compressive strength of the remaining operating areas, as well as the length value of the rock crack formed when a single hole was drilled and fractured in each operating area under different stress states.

[0051] 2. Based on the performance parameters of the rock breaking equipment, determine the diameter of the main expansion hole, the diameter of the auxiliary drilling hole, the depth of the main expansion hole and the auxiliary drilling hole, and the theoretical distance between the main expansion holes in each operation area. The diameter of the main expansion hole and the diameter of the auxiliary drilling hole must meet the following requirements:

[0052] Where r0 is the diameter of the main expansion hole, and r1 is the diameter of the auxiliary drilling hole.

[0053] Since the smaller the diameter of the drilled hole, the shorter the drilling time of the rock breaking equipment, and no subsequent expansion auxiliary drilling hole is required, the drilling efficiency is highest when the radius of the auxiliary drilling hole is half the radius of the main expansion hole.

[0054] In this embodiment, the rock breaking equipment adopts a combination of equipment commonly used in hard rock excavation, namely, a ZDY4500LPS type crawler impact drill or a pneumatic impact drill for coal mines and a hydraulic rock splitter with a hole diameter of 110 mm or a hole-type hydraulic expander. The hydraulic rock splitter can use six splitting rods for expansion at the same time, so that high pressure can be applied simultaneously at different positions in an operating area to form multiple concentrated stress points through hydraulic expansion force. These stress points interact with each other in a small range, significantly reducing the tensile strength of the rock mass, thereby more efficiently inducing the expansion of rock cracks 18.

[0055] The spacing between the two main expansion holes in each operating area is determined based on the rock fracture length value obtained from the simulation experiment and the splitting force generated by the hydraulic rock splitter theory. The formula is:

[0056]

[0057] Where, L is the theoretical distance between the two main expansion holes, R t is the length of the rock mass crack, q is the theoretical splitting force generated by the hydraulic rock splitter, in MPa. The theoretical splitting force generated by the hydraulic rock splitter is generally obtained from the performance parameter table of the hydraulic rock splitter provided by the merchant, σ t It is the simulated tensile strength, the unit is MPa, and r0 is the aperture of the main burst hole.

[0058] Specifically, the first fracturing zone 2 is a regular pentagon, and main fracturing holes are drilled at the center point and each vertex of the first fracturing zone 2 of the regular pentagon. The main fracturing hole of the first fracturing zone 2 is called the first main fracturing hole 3. Five auxiliary drilling holes are evenly opened in the first fracturing zone 2. The auxiliary drilling holes drilled in the first fracturing zone 2 are called first auxiliary drilling holes 19. The five first auxiliary drilling holes 19 are distributed in the five equilateral triangle areas formed by connecting the center point of the first fracturing zone 2 and each vertex. A hydraulic rock splitter is used to fracture the six main fracturing holes in the first fracturing zone 2.

[0059] When fracturing the first main fracturing holes 3 of the first fracturing zone 2, the six splitting rods of the hydraulic rock splitter are used to simultaneously fracture the six first main fracturing holes 3 of the first fracturing zone 2, thereby simultaneously applying pressure to the center of the first fracturing zone 2 from five angles. Under the action of the first auxiliary drilling hole 19, this helps to control the cracks generated during the fracturing of the rock mass to develop in a preset direction, effectively reducing the strength of the rock mass. The first fracturing zone 2 adopts a regular pentagonal structure because the distance from the midpoint of the regular pentagon to each vertex is the same and the lines connecting the midpoint of the regular pentagon to the vertices are symmetrical. This increases the density of the first main fracturing holes 3 and can meet the fracturing requirements of hard rock tunnels 13 with a surrounding rock strength coefficient f within the range of 10 to 12. Rocks with a surrounding rock strength coefficient f within the range of 10 to 12 include dense granite, limestone, quartz veins, and solid conglomerate.

[0060] The main bursting holes drilled in the second bursting zone 4 are called second main bursting holes 5. Multiple second main bursting holes 5 are neatly arranged in the geometric pattern of an equilateral triangle to form an orderly array structure. The auxiliary drilling holes drilled in the second bursting zone 4 are called second auxiliary drilling holes 6. Multiple second auxiliary drilling holes 6 are linearly distributed and located at the geometric center line below the center point of the second bursting zone 4 and at the edge of the second bursting zone 4. The second main bursting holes 5 are continuously and uninterruptedly burst in sequence using a layered crushing method. Furthermore, the multiple second auxiliary drilling holes 6 are linearly distributed downward from the equilateral triangle area surrounded by the main bursting holes near the bottom of the first bursting zone 2. When crushing the second bursting zone 4, the equilateral triangle area directly below the first bursting zone 2 is first bursted, and the second main bursting holes 5 directly below the equilateral triangle area are gradually burst downward until the lower edge of the second bursting zone 4. Then, all second main bursting holes 5 at the lower edge of the second bursting zone 4 are linearly burst in a continuous manner, and then the remaining second main bursting holes 5 are continuously burst upward layer by layer.

[0061] The second auxiliary drilling hole 6 is arranged at the geometric center line below the center point of the second fracturing zone 4 in order to reduce the crushing time of the second fracturing zone 4 under the action of the void effect after the first fracturing zone 2 is broken. The second auxiliary drilling hole 6 is not arranged on both sides of the geometric center line below the center point of the second fracturing zone 4 because after the equilateral triangle area directly below the first fracturing zone 2 in the second fracturing zone 4 and the second main fracturing hole 5 located directly below the equilateral triangle area are crushed, a space is formed for the rock structure between the bottom edge of the second fracturing zone 4 and the first fracturing zone 2 to deform, eliminating the pressure on the lower rock mass in the second fracturing zone 4, so that the predetermined crushing effect can be achieved without drilling the second auxiliary drilling hole 6, while further saving drilling time.

[0062] When the second main bursting hole 5 is arranged at a preset spacing, if the second main bursting hole 5 to be arranged will exceed the edge of the second bursting zone 4, then a second auxiliary drilling hole 6 is arranged at the edge of the second bursting zone 4 so that the length of the crack 18 of the second auxiliary drilling hole 6 does not exceed the second bursting zone 4.

[0063] Step S3: A fourth expansion and fracturing zone 10 is arranged in each of the multiple expanded excavation work areas 17, and a regular polygonal third expansion and fracturing zone 7 is arranged at the center of at least two fourth expansion and fracturing zones 10. The third expansion and fracturing zone 7 and the fourth expansion and fracturing zone 10 cover the entire corresponding expanded excavation work area 17. The expanded excavation work area 17 where the regular polygonal third expansion and fracturing zone 7 is arranged is located above the central work area 16.

[0064] A plurality of fourth main fracturing holes 11 are arranged in an array in the fourth fracturing zone 10. These holes are arranged in a regular triangle pattern to form an ordered array structure. A plurality of fourth auxiliary drilling holes 12 are evenly distributed along the edges of the fourth fracturing zone 10. Third main fracturing holes 8 are drilled at the center and vertices of the third fracturing zone 7, and a plurality of third auxiliary drilling holes 9 are evenly distributed within the third fracturing zone 7. This effectively prevents over-excavation and under-excavation, reduces the number of fourth main fracturing holes 11 drilled, significantly shortens drilling time, and further improves the excavation efficiency of the hard rock tunnel 13.

[0065] When crushing multiple expanded excavation work areas 17, the order from top to bottom and from left to right is followed. This crushing order is helpful for management and construction. Secondly, it can effectively prevent the upper work area from losing its support force and falling into the air after the lower work area is crushed, thereby exacerbating the problem of dust diffusion. Thirdly, it can prevent the upper work area from collapsing after the lower work area is crushed, thereby increasing the excavation workload of the lower work area and improving the excavation efficiency. Fourthly, the rock mass of the lower work area is crushed last to ensure the flatness of the tunnel after the lower work area is crushed.

[0066] When crushing and expanding the excavation operation area 17, the third expansion zone 7 is crushed first, and then the fourth main expansion hole 11 in the triangular area near the third expansion zone 7 at the bottom of the fourth expansion zone 10 is crushed. Then, the fourth main expansion hole 11 is broken in a continuous and uninterrupted manner in the direction of the geometric centerline of the free section of the hard rock tunnel 13. Then, the fourth main expansion hole 11 is broken upward layer by layer, and finally, the fourth main expansion hole 11 at the edge of the fourth expansion zone 10 is broken along the contour of the fourth expansion zone 10, forming a surrounding crushing method. If the third expansion zone 7 is not arranged in the fourth expansion zone 10, the fourth main expansion hole 11 is broken from the triangular area near the central operation area 16 in a bottom-up, layer-by-layer manner.

[0067] In this embodiment, two third fracturing zones 7 are deployed, located at the central, concentrated crushing locations of the corresponding two fourth fracturing zones 10. The two expanded excavation operating areas 17 corresponding to these two fourth fracturing zones 10 are both located above the central operating area 16. The remaining two expanded excavation operating areas 17 are located below the central operating area 16 and do not have third fracturing zones 7. This embodiment is suitable for situations where the expanded excavation operating area 17 below the central operating area 16 is relatively small and the fourth main fracturing hole 11 has a relatively large aperture. Whether to deploy third fracturing zones 7 can be determined by those skilled in the art based on limited testing and crushing experience. During crushing, the two expanded excavation operating areas 17 above the central operating area 16 are crushed first, followed by the two expanded excavation operating areas 17 below the central operating area 16. Before crushing the two expanded excavation operating areas 17 below the central operating area 16, crushing and supporting measures are performed on the two expanded excavation operating areas 17 above the central operating area 16.

[0068] In this embodiment, the third fracturing zone 7 is a regular pentagon or an equilateral triangle. When the third fracturing zone 7 is a regular pentagon, its structure is identical to that of the first fracturing zone 2. When the third fracturing zone 7 is an equilateral triangle, a third main fracturing hole 8 is provided at each of the three vertices and the midpoint of the equilateral triangle. A third auxiliary drilling hole 9 is provided at the midpoint of the line connecting two vertices of the equilateral triangle third fracturing zone 7 to guide the growth direction of cracks during fracturing in the third fracturing zone 7 and reduce the hardness of the rock mass. The equilateral triangle-shaped third fracturing zone 7 is suitable for the fracturing requirements of hard rock tunnels 13 with a surrounding rock strength coefficient f within the range of 8 to 10. Rocks with a surrounding rock strength coefficient f within the range of 8 to 10 include solid sandstone, limestone, marble, dolomite, pyrite, and weak granite.

[0069] The formula for determining the surrounding rock strength coefficient f of the hard rock tunnel 13 to be excavated is: Among them, δ c The ultimate compressive stress value when the rock mass is destroyed under compressive strength, i.e. uniaxial compression. The rock strength grade is determined according to the surrounding rock strength coefficient classification table.

[0070] The auxiliary drilling holes mainly play two roles: first, based on the principle of the void effect, drilling multiple auxiliary drilling holes around the main expansion hole can effectively increase the expansion speed of the rock mass and the development of the cracks 18; second, the auxiliary drilling holes can guide the development direction of the cracks after the main expansion hole is expanded, so as to promote the development of rock cracks in the preset direction and achieve an ideal crushing state.

[0071] After the rock mass in the current operating area is crushed, the stress distribution in the free section of the hard rock tunnel 13 changes. To improve the excavation efficiency of the hard rock tunnel 13, before crushing the rock mass in the next operating area, the stress field changes of the rock mass in the remaining operating area after crushing the rock mass in the current operating area can be re-simulated based on the hard rock tunnel 13 model, and the spacing between the two main expansion holes in the next operating area can be re-determined to achieve a hole spacing suitable for the current operation.

[0072] It should be noted that in actual crushing operations, due to the presence of irregular lithology and complex rock stability in the entire hard rock tunnel 13, the simulated distance between the two main expansion holes may deviate from the actual distance. t ≤L i ≤2R t (L i The actual distance between the two main expansion holes is dynamically adjusted within the range of (indicates the actual distance between the two main expansion holes). Among them, the actual distance between the two main expansion holes is required to be L i ≥R t In order to prevent the cracks 18 generated when two splitting rods simultaneously crack two adjacent main cracking holes from overlapping excessively and reducing the overall excavation speed, the actual spacing L between the two main cracking holes is required to be i ≤2R t This is to prevent the length of the crack 18 generated when two adjacent main cracking holes are actually cracked from not meeting the requirement of the rock crack length value.

[0073] For a hard rock tunnel 13 with high hardness and poor water absorption, when crushing the rock mass in the first expansion zone 2 of the central operating area 16, since the first expansion zone 2 is a stress concentration area, it is difficult to crush. Crushing the rock mass with relatively high hardness will increase the loss of the hydraulic rock splitter. The present invention provides another embodiment to further improve the excavation efficiency of the hard rock tunnel 13, that is, to assist the hydraulic rock splitter in crushing the rock mass by injecting high-pressure water into the operating area. Specifically, the two first auxiliary drilling holes 19 located at the upper part of the first expansion zone 2 are replaced by water injection holes 14, and the radius r2 of the water injection hole 14 is (r0 is the aperture of the main bursting hole), and at the same time, multiple drainage holes 15 are drilled in the second bursting zone 4 near the first bursting zone 2. The radius r3 of the drainage hole 15 is The central axis of the drainage hole 15 forms an angle of 15° with the central axis of the first main fracturing hole 3, wherein the central axis of the first main fracturing hole 3 is perpendicular to the free cross-section of the hard rock roadway 13. The drainage hole 15 and the water injection hole 14 cooperate to drain water injected into the water injection hole 14. In this embodiment, two drainage holes 15 are provided, respectively located in the lower left and lower right corners of the first fracturing zone 2.

[0074] The water injection hole 14 has a diameter set to meet the characteristics of the high-pressure water injection equipment on the market and to ensure that the high-pressure water is rapidly injected into the water injection hole 14 in a short time to weaken the hardness of the rock mass in the first fracturing zone 2 and effectively reduce the tensile strength of the rock mass, thereby further improving the fragmentation efficiency of the first fracturing zone 2. The drainage hole 15 has a diameter set to meet the requirement that the water injected into the first fracturing zone 2 is drained to not affect the subsequent fragmentation operation. The diameter of the water injection hole 14 and the diameter of the drainage hole 15 can be appropriately adjusted by the person skilled in the art according to the model of the high-pressure water injection equipment actually used and the actual fragmentation environment of the hard rock roadway 13.

[0075] The water injection amount into the water injection hole 14 can be obtained by simulation experiments based on the model of the hard rock roadway 13 to be fragmented, and the influence of the high-pressure water injected into the two water injection holes 14 on the rock stress in the operation area before the first fracturing zone 2 is fragmented. A plurality of sets of experimental data are measured and analyzed and compared through multiple simulation experiments to determine the optimal water injection amount that can reduce the tensile strength of the rock mass.

[0076] The reason for only using the hydraulic rock splitting machine to cooperate with the injection of high-pressure water into the operation area to fragment the rock mass in the first fracturing zone 2 is that the action mechanism of the two pressures on the rock mass is complex, and once the action range is too large, the overall stability of the rock mass is easily damaged. Therefore, in the embodiment, the front hard rock roadway 13 is provided with advance support to improve the overall stability of the surrounding rock under the condition that the condition permits, and then high-pressure water is injected into the operation area to assist in fragmenting the first fracturing zone 2. After the rock mass in the first fracturing zone 2 is fragmented, the water injected into the first fracturing zone 2 is drained through the drainage hole 15, and then the conventional hydraulic fracturing operation is carried out, that is, the hydraulic rock splitting machine is used to fracture the main fracturing hole to fragment the rock mass in the operation area.

[0077] More specifically, when the hydraulic rock splitting machine is used to cooperate with the injection of high-pressure water into the operation area to fragment the rock mass in the first fracturing zone 2, high-pressure water is first injected into the two water injection holes 14 to reduce the tensile strength of the rock in the working area, and then the hydraulic rock splitting machine is used to sequentially fracture a plurality of first main fracturing holes 3 in sequence. When the first main fracturing hole 3 is fractured, the sequence from top to bottom is followed, that is, the upper region of the first fracturing zone 2 is first fragmented, which facilitates the drainage of the water injected into the water injection hole 14 from the drainage hole 15, so as not to affect the tunneling speed of the overall hard rock roadway 13. After the injected high-pressure water is completely drained, the lower region of the first fracturing zone 2 is fragmented.

[0078] Regarding the specific structure of the present invention, it should be noted that the connection relationship between the various component modules adopted in the present invention is definite and feasible. Except for those specifically described in the embodiments, the specific connection relationship can bring about corresponding technical effects and solve the technical problems raised by the present invention without relying on the execution of corresponding software programs. The components, modules, models of specific components appearing in the present invention, the connection methods between each other, and the conventional usage methods and expected technical effects brought about by the above-mentioned technical features, except for those specifically described, all belong to the disclosed contents in patents, journal articles, technical manuals, technical dictionaries, and textbooks that can be obtained by technical personnel in this field before the application date, or belong to the existing technologies such as conventional technology and common knowledge in this field. There is no need to elaborate, so that the technical solution provided in this case is clear, complete, and feasible, and the corresponding physical products can be reproduced or obtained based on this technical means.

[0079] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A drilling method for rapid rock breaking and excavation in hard rock tunnels, characterized in that: The following steps are involved: Step S1, dividing the free section of the hard rock tunnel (13) into a plurality of operating areas, namely a central operating area (16) and a plurality of expanded excavation operating areas (17), wherein the plurality of expanded excavation operating areas (17) are distributed around the central operating area (16); Step S2, arranging a first expansion zone (2) in the shape of a regular polygon and second expansion zones (4) distributed around the first expansion zone (2) in the central operating area (16), drilling a first main expansion hole (3) at the center point and each vertex in the first expansion zone (2), and evenly opening a plurality of first auxiliary drilling holes (19) in the first expansion zone (2); drilling a plurality of second main expansion holes (5) and a plurality of second auxiliary drilling holes (6) in the second expansion zone (4), wherein the plurality of second main expansion holes (5) are distributed in an array in the shape of a regular triangle, and the plurality of second auxiliary drilling holes (6) are distributed on a preset expansion path of the second expansion zone (4) and at the edge of the second expansion zone (4); after arranging the first main expansion holes (3) and the second main expansion holes (5), using rock breaking equipment to simultaneously expand the plurality of first main expansion holes (3) in the first expansion zone (2), and then expanding the second main expansion holes (5) in the second expansion zone (4) in sequence from top to bottom and from the center to the periphery; When the second bursting zone (4) is broken, the equilateral triangle area directly below the first bursting zone (2) is first bursted, and the second main bursting holes (5) located directly below the equilateral triangle area are gradually bursted downward until the lower edge of the second bursting zone (4), and then all the second main bursting holes (5) at the lower edge of the second bursting zone (4) are linearly bursted in a continuous manner, and then the remaining second main bursting holes (5) are bursted upward layer by layer in a continuous manner; Step S3, respectively arranging a fourth expansion and fracturing zone (10) in a plurality of expanded excavation operation areas (17), arranging a third expansion and fracturing zone (7) in the shape of a regular polygon at the center of at least two fourth expansion and fracturing zones (10), drilling a third main expansion and fracturing hole (8) at the center point and each vertex of the third expansion and fracturing zone (7), and evenly opening a plurality of third auxiliary drilling holes (9) in the third expansion and fracturing zone (7); opening a plurality of fourth main expansion and fracturing holes (11) distributed in an array in the shape of a regular regular regular triangle in the fourth expansion and fracturing zone (10), and evenly opening a plurality of fourth auxiliary drilling holes (12) at the edge of the fourth expansion and fracturing zone (10); after arranging the third auxiliary drilling holes (9) and the fourth auxiliary drilling holes (12), the plurality of expanded excavation operation areas (17) are broken in sequence from top to bottom and from left to right.

2. A drilling method for rapid rock breaking and excavation in a hard rock tunnel according to claim 1, characterized in that: The first bursting zone (2) is a regular pentagon, and five first auxiliary drilling holes (19) are opened. The five first auxiliary drilling holes (19) are distributed in five regular triangle areas formed by connecting the center point of the first bursting zone (2) and each vertex.

3. The drilling method for rapid rock breaking and excavation in a hard rock tunnel according to claim 1, characterized in that: In step S2, when the second main bursting holes (5) are arranged at a preset interval, if the second main bursting holes (5) to be arranged will exceed the edge of the second bursting zone (4), a second auxiliary drilling hole (6) is arranged at the edge of the second bursting zone (4) so ​​that the length of the crack (18) of the second auxiliary drilling hole (6) does not exceed the second bursting zone (4).

4. The drilling method for rapid rock breaking and excavation in a hard rock tunnel according to claim 1, characterized in that: When the excavation operation area (17) is crushed and expanded in step S3, the third expansion zone (7) is crushed first, and then the fourth main expansion hole (11) in the triangular area of ​​the lower part of the fourth expansion zone (10) adjacent to the third expansion zone (7) is crushed, and then the fourth main expansion hole (11) is broken in a continuous and uninterrupted manner in the direction of the geometric center line of the free section of the hard rock tunnel (13), and then the fourth main expansion hole (11) is broken upward layer by layer, and finally the fourth main expansion hole (11) at the edge of the fourth expansion zone (10) is crushed along the outline of the fourth expansion zone (10), forming a surrounding crushing method.

5. The drilling method for rapid rock breaking and excavation in a hard rock tunnel according to claim 1, characterized in that: In step S3, two third expansion and fracturing zones (7) are arranged. The two third expansion and fracturing zones (7) are respectively located at the central concentrated crushing locations of the corresponding two fourth expansion and fracturing zones (10). The two expanded excavation operation zones (17) corresponding to the two fourth expansion and fracturing zones (10) are both located above the central operation zone (16). The remaining expanded excavation operation zones (17) are located below the central operation zone (16) and are not arranged with the third expansion and fracturing zones (7).

6. The drilling method for rapid rock breaking and excavation in a hard rock tunnel according to claim 1, characterized in that: The third bursting zone (7) is a regular pentagon or a regular triangle.

7. The drilling method for rapid rock breaking and excavation in a hard rock tunnel according to claim 1, characterized in that: In step S3, before crushing the next operating area, the distance between the two main expansion holes arranged in the next operating area is dynamically adjusted.

8. The drilling method for rapid rock breaking and excavation in a hard rock tunnel according to claim 1, characterized in that: High-pressure water is injected into the first expansion and fracturing zone (2) to assist the rock breaking equipment in fracturing the rock mass in the first expansion and fracturing zone (2).

9. The drilling method for rapid rock breaking and excavation in a hard rock tunnel according to claim 1, characterized in that: The first expansion and rupture zone (2) is provided with a plurality of water injection holes (14), and the second expansion and rupture zone (4) is provided with a plurality of drainage holes (15), and the water injection holes (14) and the drainage holes (15) cooperate with each other.

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