Method for forming a hole in hard rock layer by rotary drilling rig

Abstract

The application provides a hard rock stratum hole-forming method of a rotary drilling rig, and belongs to the technical field of rock stratum drilling. The method comprises the following steps: when a hard rock stratum is not reached, drilling is performed in a stratum by using a rotary drilling rig; when the hard rock stratum is reached, the rotary drilling rig is first braked, and an impactor in the middle of the rotary drilling rig is extended, the impactor is used to impact the hard rock stratum to form a broken hole; after the length of the broken hole reaches a specified requirement, the impactor is reset; a plurality of cutters at the end of the rotary drilling rig are extended, the rotary drilling rig is started, and the rotary drilling rig drives the plurality of cutters to move, the plurality of cutters are used to cut the hard rock stratum in sequence on the basis of the broken hole, the inner diameter of the broken hole is gradually increased until the requirement is met; after the hard rock stratum is penetrated, the plurality of cutters are retracted, and the rotary drilling rig continues to perform rotary drilling. The hard rock stratum hole-forming method of the rotary drilling rig improves the hole-forming efficiency of the hard rock stratum of the rotary drilling rig, prolongs the service life of the rotary drilling rig, and shortens the construction period.

Description

Technical Field

[0001] This invention belongs to the field of rock drilling technology, and more specifically, relates to a method for drilling holes in hard rock formations using rotary drilling rigs. Background Technology

[0002] Traditional large-diameter rock-socketed pile drilling requires the use of rotary drilling rigs, employing fixed-diameter scraper bits and roller bits to drill through the overburden and rock-socketed layers respectively. In this traditional process, the rotary drill rollers gradually grind the rock into fragments of 5mm to 10mm in diameter, which are then removed via air-lift reverse circulation through the drill rod. This method is inefficient and difficult to execute when the rock is hard. Furthermore, since each pile location is drilled by only one independent drilling rig, the process is time-consuming and detrimental to project schedule control.

[0003] Rotary drilling is a fast construction technology with high hole-forming efficiency. With appropriate drilling tools, it can be used to drill holes in various strata, including fill, clay, silt, sand, and even pebbles and pure rock. However, it is also slow and inefficient in medium- and hard rock strata with relatively intact bedding and fractures, which ultimately leads to a longer construction period. Summary of the Invention

[0004] The purpose of this invention is to provide a method for drilling holes in hard rock formations using rotary drilling rigs, aiming to solve the problems of slow construction speed and low efficiency when drilling holes in hard rock formations using rotary drilling rigs.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is: to provide a method for drilling holes in hard rock formations using a rotary drilling rig, comprising:

[0006] Before reaching the hard rock layer, a rotary drilling rig is used to drill holes within the strata;

[0007] When the hard rock layer is reached, the rotary drilling rig is first braked and the impactor in the middle of the rotary drilling rig is extended. The impactor impacts the hard rock layer to form a fracture hole. After the length of the fracture hole reaches the specified requirement, the impactor is reset.

[0008] Extend multiple cutter heads from the end of the rotary drilling rig, start the rotary drilling rig and drive the multiple cutter heads to move, so that the multiple cutter heads cut the hard rock layer in sequence based on the broken hole, so that the inner diameter of the broken hole gradually increases until the requirements are met;

[0009] After penetrating the hard rock layer, the multiple cutter heads are retracted and the rotary drilling rig continues rotary drilling.

[0010] In one possible implementation, drilling within the formation using a rotary drilling rig includes:

[0011] Before reaching hard rock layers, the impactor rotates together with the rotary drilling rig and drills a hole.

[0012] In one possible implementation, the step of first braking the rotary drilling rig and extending the impactor in the middle of the rotary drilling rig upon reaching a hard rock layer includes:

[0013] The rotary drilling rig uses multiple sensors to detect and assess the orientation and hardness of hard rock formations in real time.

[0014] In one possible implementation, the real-time detection and judgment of the strike and hardness of the hard rock layer based on feedback from multiple sensors on the rotary drilling rig includes:

[0015] The detection range of the corresponding sensor is determined based on the angle of the rotary drilling rig.

[0016] The orientation of the hard rock layer can be determined by the images taken.

[0017] The hardness of the hard rock layer is inferred by sensors on the drill bit of the rotary drilling rig.

[0018] In one possible implementation, the step of first braking the rotary drilling rig and extending the impactor in the middle of the rotary drilling rig upon reaching a hard rock layer includes:

[0019] The impactor is coaxially mounted with the rotary drilling rig; when it reaches a hard rock layer, the impactor extends from the middle of the rotary drilling rig.

[0020] In one possible implementation, the step of first braking the rotary drilling rig and extending the impactor in the middle of the rotary drilling rig upon reaching a hard rock layer includes:

[0021] The rotary drilling rig is braked and positioned within the formation. The impactor is pushed by the guide rod, and the impactor gradually breaks up the hard rock layer.

[0022] In one possible implementation, extending the plurality of cutter heads at the end of the rotary drilling rig includes:

[0023] In the initial state, multiple cutter heads are disposed inside the rotary drilling rig;

[0024] After reaching the hard rock layer and the impactor resets, multiple cutter heads extend sequentially from inside the rotary drilling rig, with the cutter head closer to the axis of the rotary drilling rig being further away from the end of the rotary drilling rig.

[0025] In one possible implementation, the greater the distance between the cutter head, which is closer to the axis of the rotary drilling rig, and the end of the rotary drilling rig, includes:

[0026] By defining the positions of the multiple cutting heads, after the previous cutting head cuts a certain length into the hard rock layer, the next cutting head cuts again on the newly formed cutting surface, thereby gradually enlarging the fracture hole.

[0027] In one possible implementation, starting the rotary drilling rig and causing the rotary drilling rig to drive the plurality of cutter heads to move includes:

[0028] The rotary drilling rig drives multiple cutter heads to move in two directions, one direction being rotation along the axial direction of the rotary drilling rig, and the other direction being rotation around the circumference of the rotary drilling rig.

[0029] In one possible implementation, starting the rotary drilling rig and causing the rotary drilling rig to drive the plurality of cutter heads to move includes:

[0030] Multiple cutter heads are mounted on a support frame, which is slidably disposed inside the rotary drilling rig and has only one degree of freedom to slide along the axial direction of the rotary drilling rig.

[0031] The beneficial effects of the rotary drilling rig hole-forming method in hard rock formations provided by this invention are as follows: Compared with the prior art, in this invention's method, before reaching the hard rock formation, the rotary drilling rig drills within the strata. Upon reaching the hard rock formation, the rotary drilling rig is first activated, and the impactor in the middle of the rig extends, impacting the hard rock formation to form a broken hole. Once the length of the broken hole reaches the specified requirement, the impactor is reset. After the impactor resets, multiple cutter heads extend from the end of the rotary drilling rig, which then starts and drives the multiple cutter heads to move, sequentially cutting the hard rock formation based on the broken hole, gradually increasing the inner diameter of the broken hole until the requirement is met.

[0032] In this application, by setting a cutter head and an impactor, the hard rock layer can be gradually cut after reaching it, thereby improving the drilling efficiency of the rotary drilling rig in hard rock layers, extending the service life of the rotary drilling rig, and shortening the construction period. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 This is a flowchart of a rotary drilling method for drilling holes in hard rock formations, provided in an embodiment of the present invention. Detailed Implementation

[0035] To make the technical problems to be solved, the technical solutions, and the beneficial effects 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 merely illustrative of the present invention and are not intended to limit the present invention.

[0036] Please see Figure 1 The present invention will now describe the method for drilling holes in hard rock formations using a rotary drilling rig. The method includes:

[0037] Before reaching the hard rock layer, a rotary drilling rig is used to drill holes in the strata.

[0038] When reaching the hard rock layer, first brake the rotary drilling rig and extend the impactor in the middle of the rotary drilling rig. The impactor will then impact the hard rock layer to form a fracture hole. After the length of the fracture hole reaches the specified requirement, reset the impactor.

[0039] Extend multiple cutter heads from the end of the rotary drilling rig, start the rotary drilling rig and drive the multiple cutter heads to move, so that the multiple cutter heads cut the hard rock layer in sequence based on the broken hole, so that the inner diameter of the broken hole gradually increases until the requirements are met.

[0040] After penetrating the hard rock layer, multiple cutter heads are retracted and the rotary drilling rig continues rotary drilling.

[0041] The beneficial effects of the rotary drilling rig hole-forming method in hard rock formations provided by this invention are as follows: Compared with the prior art, in this invention's method, before reaching the hard rock formation, the rotary drilling rig drills within the strata. Upon reaching the hard rock formation, the rotary drilling rig is first activated, and the impactor in the middle of the rig extends, impacting the hard rock formation to form a broken hole. Once the length of the broken hole reaches the specified requirement, the impactor is reset. After the impactor resets, multiple cutter heads extend from the end of the rotary drilling rig, which then starts and drives the multiple cutter heads to move, sequentially cutting the hard rock formation based on the broken hole, gradually increasing the inner diameter of the broken hole until the requirement is met.

[0042] In this application, by setting a cutter head and an impactor, the hard rock layer can be gradually cut after reaching it, thereby improving the drilling efficiency of the rotary drilling rig in hard rock layers, extending the service life of the rotary drilling rig, and shortening the construction period.

[0043] In pile foundation construction, rotary drilling is a major construction project. When the compressive strength of the rock reaches 60 MPa or higher, conventional rotary drilling cannot be used due to the rock's hardness. Conventional methods include manual excavation or percussion drilling, but both have their drawbacks. Manually excavated pile construction requires blasting or water-cooled drilling to advance the pile. Blasting is low-cost and fast, but has high environmental requirements and significant safety risks. Water-cooled drilling is expensive, slow, and poses significant safety risks when used manually. Percussion drilling is low-cost and has low safety risks, but is slow. While these two methods can address the construction of bored piles in ultra-hard rock formations, they still suffer from low mechanization, slow speed, high cost, and high safety risks, especially pronounced in the construction of large-diameter bored piles.

[0044] Percussion drilling is suitable for constructing rock-embedded end-bearing piles under ordinary geological conditions. However, in permafrost areas, due to the slow drilling speed and significant thermal disturbance, borehole collapse is prone to occur, making direct percussion drilling unsuitable for pile foundation construction in island-like permafrost regions. Rotary drilling offers advantages such as high speed, no need for mud slurry wall protection, and the ability to perform dry drilling, reducing disturbance and heat exchange in the island-like permafrost layer. Rotary drilling is suitable for construction in sandy, cohesive, and silty soil layers, but it cannot drill into rock strata, resulting in low utilization rates in rocky areas, thus also failing to meet the requirements for rock-embedded pile construction in island-like permafrost regions.

[0045] Rotary drilling rigs are one of the most commonly used equipment in cast-in-place pile construction. They are suitable for various soil and rock formations. For hard rock formations, cutting teeth or roller cones are generally used for drilling, or core sampling is performed directly, or the rotary drilling bucket is replaced to retrieve rock debris.

[0046] In some embodiments of the rotary drilling method for drilling holes in hard rock formations provided in this application, drilling within the formation using a rotary drilling rig includes:

[0047] Before reaching hard rock layers, the impactor rotates together with the rotary drilling rig and drills a hole.

[0048] In current domestic bridge pile and other foundation construction, rotary drilling is a relatively advanced construction method. Rotary drilling is an advanced, high-quality, and efficient construction technology. Its standard configuration can basically meet the construction requirements of bored piles and is suitable for various pile foundation constructions, offering significant advantages over impact drilling. However, rotary drilling rigs are mainly suitable for construction in soil layers such as sand, cohesive soil, and silty soil. This is because rotary drilling relies on the weight and pressure of the drill rod and drill bit to cut into the soil layer and rotate to extract soil.

[0049] Percussion drilling is a relatively traditional construction technique. Its characteristic is that it relies on the weight and impact of the cone to directly impact and break up soil and rock, using drilling mud to suspend the drill cuttings. Because percussion drilling involves a relatively small agitation range of the drilling mud within the hole, it is less likely to erode the mud wall, allowing the mud wall to provide good stability and preventing collapse or borehole failure. This method is suitable for most strata, including sub-clay, sandy soil, gravel, pebbles, boulders, soft rock, and hard rock. When using rotary drilling rigs to drill holes in hard rock formations, the high hardness of the rock requires a long time for the drill bit to penetrate, resulting in lower overall efficiency and significantly reduced drill bit lifespan. Once the drill bit is severely worn and needs replacement, it severely impacts the construction progress and efficiency.

[0050] For the reasons mentioned above, how to integrate impact drilling and rotary drilling to improve the overall drilling efficiency is a technical problem that urgently needs to be solved.

[0051] In some embodiments of the rotary drilling rig hole-forming method for hard rock formations provided in this application, when the hard rock formation is reached, first activating the rotary drilling rig and extending the impactor in the middle of the rotary drilling rig includes:

[0052] The direction and hardness of hard rock strata are detected and judged in real time by the feedback from multiple sensors on the rotary drilling rig.

[0053] When performing rotary drilling, the outer diameter of the rotary drilling bit is usually large, which can ensure that the final hole specifications meet the requirements to a certain extent. However, the rotary drilling cannot improve the tunneling efficiency through impact like an impact drill. That is, the rotary drilling can only drill holes gradually through multiple drill bits on the end face.

[0054] Impact drills have a relatively small overall outer diameter. Based on these characteristics, impact drilling is a common method for pile foundation construction. Impact drilling generally uses an impact drill bit to drill into the pile hole. During the impact drilling process, a large amount of diluted mud will be present in the pile hole. As the impact drill bit continuously impacts and drills into the bottom of the pile hole, the rock strata at the bottom of the pile hole are gradually broken. The broken stone chips will be suspended in the mud. Then, the construction personnel will use forward or reverse circulation to carry out the mud containing the suspended stone chips in the pile hole and continuously inject diluted mud into the pile hole. This continuous impact drilling will continuously carry out the stone chips formed by impact through the mud, thereby achieving the purpose of impact drilling.

[0055] The purpose of this application is to integrate the two and ultimately improve the drilling efficiency of hard rock formations and shorten the overall drilling time.

[0056] In some embodiments of the rotary drilling rig hole-forming method for hard rock formations provided in this application, the real-time detection and judgment of the strike and hardness of the hard rock formations based on feedback from multiple sensors on the rotary drilling rig includes:

[0057] The detection range of the corresponding sensor is determined based on the current angle of the rotary drilling rig.

[0058] The orientation of the hard rock layer can be determined by taking pictures.

[0059] The hardness of hard rock layers is inferred by sensors on the drill bit of a rotary drilling rig.

[0060] It should be noted that the entire rotary drilling bit moves gradually downwards as it cuts through the rock strata with multiple cutters. That is, the entire rotary drilling bit has two directions of movement: one is downward movement, and the other is rotation along its own axis.

[0061] Whether multiple cutter heads should cut the rock layer depends on the hardness of the current rock layer. Therefore, in practical applications, multiple sensors on the rotary drilling bit can collect information such as the hardness of the rock layer in real time, while the camera and other components on the rotary drilling rig can take pictures of the rock layer in real time. By feeding back the current direction of the rock layer to the host computer in real time, the host computer can judge the current rock layer condition based on the feedback, and thus determine whether multiple cutter heads are needed to cut the rock layer, or whether the drill bit of the rotary drilling rig can be used for drilling.

[0062] In some embodiments of the rotary drilling rig hole-forming method for hard rock formations provided in this application, when the hard rock formation is reached, first activating the rotary drilling rig and extending the impactor in the middle of the rotary drilling rig includes:

[0063] The impactor is coaxially mounted with the rotary drilling rig; when hard rock strata are reached, the impactor extends from the middle of the rotary drilling rig.

[0064] Compared to rotary drilling, percussion drills are relatively more efficient at drilling holes in hard rock formations. By using the impact force of the drill bit, the rock is broken into smaller pieces, thus achieving the purpose of drilling. The percussion drill referred to in this application can be understood as a down-the-hole hammer.

[0065] Pneumatic down-the-hole hammers have gained significant attention in the field of rock breaking machinery due to their advantages such as simple structure, convenient operation, easy maintenance, effective removal of rock cuttings from the bottom of wells, no limitation on drilling depth, and reduced drill bit wear. With the rapid development of pneumatic down-the-hole hammer drilling technology, its application areas have continuously expanded, evolving from initial blasting hole construction to almost all drilling construction fields, including hydrological well drilling, geological core exploration, reservoir dam foundation curtain grouting, engineering geological exploration, trenchless pipeline laying, building foundations, and geotechnical engineering.

[0066] To provide a more detailed explanation, this application integrates the impactor and the rotary drilling rig. In one embodiment, the impactor is installed and positioned at the central axis of the rotary drilling rig bit. During the actual drilling process, the down-the-hole impactor first breaks up a specific area of ​​the rock strata to form a fractured hole, and then the rotary drilling rig enlarges the fractured hole.

[0067] In some embodiments of the rotary drilling rig hole-forming method for hard rock formations provided in this application, when the hard rock formation is reached, first activating the rotary drilling rig and extending the impactor in the middle of the rotary drilling rig includes:

[0068] The rotary drilling rig is braked and positioned within the formation. The impactor is pushed by the guide rod, and the impactor gradually breaks up the hard rock layer.

[0069] In practical applications, when the formation hardness is low, the drill bit on the impactor and the drill bit of the rotary drilling rig are flush. During drilling, the rotary drilling bit and the impactor drill bit contact the formation and rotate together. In some embodiments, the impactor can be considered to be stationary while the rotary drilling rig drives its rotation. In this case, it is necessary to ensure the reliability and stability of the connection between the impactor and the rotary drilling rig.

[0070] When encountering hard rock formations, the rotary drilling rig stops rotating. The guide rod can be used to push the impactor inside the rotary drilling rig to perform impact drilling. In other words, the impactor is pushed out of the rotary drilling rig, and during the pushing process, the impactor breaks up the rock formation and forms a hole.

[0071] In some embodiments of the rotary drilling rig hole-forming method for hard rock formations provided in this application, extending multiple cutter heads from the end of the rotary drilling rig includes:

[0072] In the initial state, multiple cutter heads are located inside the rotary drilling rig.

[0073] After reaching the hard rock layer and the impactor resets, multiple cutter heads extend sequentially from inside the rotary drilling rig, with the cutter head closer to the axis of the rotary drilling rig being further away from the end of the rig.

[0074] After drilling a hole of a certain length in hard rock using an impactor, operating the rotary drilling rig at this point will still result in low efficiency. To address this, after drilling a certain distance with the impactor, it is retracted into the rotary drilling rig. This creates a fracture hole within the rock formation, which has a certain length but a relatively small inner diameter.

[0075] In order to drill holes in rock formations using rotary drilling rigs, the drill bits of traditional rotary drilling rigs need to be modified. One embodiment involves mounting multiple cutter heads sequentially on the drill bit of the rotary drilling rig.

[0076] For ease of understanding, an electric push rod is installed and fixed inside the rotary drilling rig. During normal use of the rotary drilling rig, multiple cutter heads are located inside the rig and do not come into contact with the outside. When encountering rock formations, the electric push rod pushes multiple cutter heads out of the rig and makes them contact the rock formations before the drill bit.

[0077] In some embodiments of the rotary drilling rig hole-forming method for hard rock formations provided in this application, the distance between the cutter head closer to the axis of the rotary drilling rig and the end of the rotary drilling rig is greater, including:

[0078] By limiting the position of multiple cutting heads, after the previous cutting head cuts a certain length into the hard rock layer, the next cutting head cuts again on the newly formed cutting surface, so as to gradually enlarge the fracture hole.

[0079] The multiple cutter heads are of the same specification but differ in position. The cutter head closest to the center of the rotary drilling rig is on the outermost edge and thus contacts the rock layer first. In reality, this cutter head is the farthest from the drill bit, while the cutter head located at the outermost edge of the rotary drilling rig is closest to the drill bit. Simultaneously, the positions of the multiple cutter heads are adjusted accordingly based on the direction of rotation of the rotary drilling rig, thereby completing the gradual cutting of the rock layer.

[0080] In practical application, the impactor first creates a fracture hole. After impacting a certain length, the impactor returns to its original position inside the rotary drilling rig. At this point, multiple cutter heads move a certain distance towards the rock stratum. When the outermost cutter head, closest to the center, contacts the rock stratum, the rotary drilling rig drives the multiple cutter heads to rotate. The outermost cutter head then contacts the rock stratum first, cutting and increasing the inner diameter of the fracture hole. After the outermost cutter head has cut a certain length, the second outermost cutter head cuts further, expanding the fracture hole. This process is repeated until the entire fracture hole is enlarged to the specified size.

[0081] In some embodiments of the rotary drilling rig hole-forming method for hard rock formations provided in this application, starting the rotary drilling rig and causing it to drive multiple cutter heads to move includes:

[0082] The rotary drilling rig drives multiple cutter heads to move in two directions: one direction is rotation along the axis of the rotary drilling rig, and the other direction is rotation around the circumference of the rotary drilling rig.

[0083] By sequentially cutting the rock strata with multiple cutter heads, the rupture hole drilled by the impactor can be enlarged to a preset size. At this point, the rock strata are cut into multiple fragments by the multiple cutter heads, and these fragments accumulate inside the rupture hole and in the enlarged space. Because the rotary drilling rig is also rotating while driving the multiple cutter heads, this configuration allows the rotary drilling rig to absorb and ultimately remove the cut rock fragments during rotation, thus enabling continuous drilling.

[0084] In some embodiments of the rotary drilling rig hole-forming method for hard rock formations provided in this application, starting the rotary drilling rig and causing it to drive multiple cutter heads to move includes:

[0085] Multiple cutter heads are mounted on a support frame, which is slidably positioned inside the rotary drilling rig and has only the freedom to slide along the axial direction of the rotary drilling rig.

[0086] Multiple cutter heads are fixed on the same side of the support frame, and all of them are positioned facing the end of the rotary drilling rig. The cutter heads only extend from inside the rotary drilling rig when cutting the rock strata.

[0087] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for drilling holes in hard rock formations using a rotary drilling rig, characterized in that, include: Before reaching the hard rock layer, a rotary drilling rig is used to drill holes within the strata; When the hard rock layer is reached, the rotary drilling machine is first braked and the impactor in the middle of the rotary drilling machine is extended. The impactor impacts the hard rock layer to form a fracture hole. Once the length of the break hole reaches the specified requirement, the impactor is reset. Extend multiple cutter heads from the end of the rotary drilling rig, start the rotary drilling rig and drive the multiple cutter heads to move, so that the multiple cutter heads cut the hard rock layer in sequence based on the broken hole, so that the inner diameter of the broken hole gradually increases until the requirements are met; In the initial state, multiple cutter heads are located inside the rotary drilling rig. After reaching the hard rock layer and the impactor resets, the multiple cutter heads extend sequentially from inside the rotary drilling rig, with the cutter head closer to the axis of the rotary drilling rig being farther from the end of the rig. By limiting the position of the multiple cutter heads, after the previous cutter head cuts a certain length into the hard rock layer, the next cutter head cuts again on the newly formed cutting surface, thereby gradually enlarging the broken hole. After penetrating the hard rock layer, the multiple cutter heads are retracted and the rotary drilling rig continues rotary drilling.

2. The method for drilling holes in hard rock formations using a rotary drilling rig as described in claim 1, characterized in that, The drilling within the formation using a rotary drilling rig includes: Before reaching hard rock layers, the impactor rotates together with the rotary drilling rig and drills a hole.

3. The method for drilling holes in hard rock formations using a rotary drilling rig as described in claim 1, characterized in that, The step of first activating the rotary drilling rig and extending the impactor in the middle of the rotary drilling rig upon reaching a hard rock layer includes: The rotary drilling rig uses multiple sensors to detect and assess the orientation and hardness of hard rock formations in real time.

4. The method for drilling holes in hard rock formations using a rotary drilling rig as described in claim 3, characterized in that, The real-time detection and judgment of the strike and hardness of hard rock layers based on feedback from multiple sensors on the rotary drilling rig includes: The detection range of the corresponding sensor is determined based on the angle of the rotary drilling rig. The orientation of the hard rock layer can be determined by the images taken. The hardness of the hard rock layer is inferred by sensors on the drill bit of the rotary drilling rig.

5. The method for drilling holes in hard rock formations using a rotary drilling rig as described in claim 1, characterized in that, The step of first activating the rotary drilling rig and extending the impactor in the middle of the rotary drilling rig upon reaching a hard rock layer includes: The impactor is coaxially mounted with the rotary drilling rig; when it reaches a hard rock layer, the impactor extends from the middle of the rotary drilling rig.

6. The method for drilling holes in hard rock formations using a rotary drilling rig as described in claim 1, characterized in that, The step of first activating the rotary drilling rig and extending the impactor in the middle of the rotary drilling rig upon reaching a hard rock layer includes: The rotary drilling rig is braked and positioned within the formation. The impactor is pushed by the guide rod, and the impactor gradually breaks up the hard rock layer.

7. The method for drilling holes in hard rock formations using a rotary drilling rig as described in claim 1, characterized in that, Starting the rotary drilling rig and causing it to drive the multiple cutter heads to move includes: The rotary drilling rig drives multiple cutter heads to move in two directions, one direction being rotation along the axial direction of the rotary drilling rig, and the other direction being rotation around the circumference of the rotary drilling rig.

8. The method for drilling holes in hard rock formations using a rotary drilling rig as described in claim 7, characterized in that, Starting the rotary drilling rig and causing it to drive the multiple cutter heads to move includes: Multiple cutter heads are mounted on a support frame, which is slidably disposed inside the rotary drilling rig and has only one degree of freedom to slide along the axial direction of the rotary drilling rig.

Images