A rotary drilling rig construction method for hard rock pile formation

Abstract

The present invention relates to the technical field of rotary drilling rig construction, and in particular to a rotary drilling rig construction method for hard rock pile formation, comprising: obtaining an ultrasonic wave velocity attenuation rate to adjust the original process parameters of the pile formation hole under the condition of determining the presence of cracks to obtain implementation process parameters; obtaining the high-frequency vibration energy and drilling speed of the barrel drill bit during drilling using the implementation process parameters, determining a corresponding pressure adjustment coefficient based on the longitudinal runout amplitude of the drill pipe to increase the drilling pressure, and obtaining the amount of returned slag in real time and correcting the pressure adjustment coefficient based on the fluctuation amplitude of the slag amount; obtaining an undulation curve of the barrel drill bit during the drilling process to determine whether the suction process of the drill slag is qualified based on the matching degree, and increasing the suction power of the sand and gravel pump or increasing the mud viscosity based on the distribution ratio of the particle size in the returned slag; and obtaining the shape uniformity of the returned slag to restore the implementation process parameters to the original process parameters. The present invention improves the hole wall stability of hard rock pile formation holes.

Description

Technical Field

[0001] The invention relates to the technical field of rotary drilling rig construction, and in particular to a rotary drilling rig construction method for hard rock pile formation. Background Art

[0002] In hard rock pile construction, fractured strata, due to the presence of natural or structural fractures, such as tensile and shear fractures, poor rock integrity, and low cementation, present a typical complex geological scenario for rotary drilling rigs. Existing drilling rigs in fractured strata often rely on experience or fixed patterns when selecting drilling parameters such as rotation speed, drilling pressure, and pump rate, lacking precise adaptation to the dynamic relationship between fracture development, such as joint density, fracture width, filler properties, and borehole wall stability. When the drilling pressure is too high, the impact load of the drill bit is easily transmitted and expanded along the fracture surface, causing the borehole wall to fall off or even collapse. Excessive rotation speed exacerbates the erosion of the fracture surface by the flushing fluid, destroying the protective mud layer on the borehole wall and causing leakage or local instability. Insufficient pump rate prevents timely removal of rock cuttings and causes them to accumulate at the fracture opening, increasing the pressure on the borehole wall and further reducing stability. These problems often lead to quality accidents such as borehole wall collapse, pile hole deviation, and low drilling efficiency, seriously restricting the safety and economic efficiency of hard rock pile construction.

[0003] Chinese patent application publication number: CN117005392A discloses a large-diameter bored pile construction process for hard rock, which adopts a method of combining rotary drilling with blasting technology to solve the problems of high labor intensity, low construction efficiency and poor safety of existing large-diameter bored pile construction in mountainous areas. The application uses a rotary drilling rig to first obtain core soil from the center of the bored pile, and then uses manual drilling to set blastholes around the core soil of the bored pile section for loosening blasting; then uses a rotary drilling rig to perform secondary drilling to remove the slag, and at the same time cleans the hole wall for protection, and repeats the process until the designed hole depth is reached to complete the bored pile construction; the application uses a rotary drilling rig to drill large-diameter bored piles in combination with blasting technology, which greatly improves construction efficiency, accelerates the overall bridge construction progress, reduces labor intensity, and reduces safety risks; the construction cost and energy consumption are low, and it has good promotion prospects and application value.

[0004] The existing technology also has the following problems: in the existing technology, when encountering fractured strata during the drilling process of pile holes in hard rock, the construction parameters of the rotary drilling rig cannot be accurately adjusted, resulting in poor hole wall stability. Summary of the Invention

[0005] To this end, the present invention provides a rotary drilling rig construction method for hard rock pile formation, which is used to overcome the problem in the prior art that when encountering fractured strata during the drilling process of pile holes in hard rock, the construction parameters of the rotary drilling rig cannot be accurately adjusted, resulting in poor hole wall stability.

[0006] To achieve the above object, the present invention provides a rotary drilling rig construction method for hard rock pile formation, comprising:

[0007] Obtaining the wave velocity attenuation rate of the ultrasonic wave during the drilling process of the rotary drilling rig to adjust the original process parameters of the pile hole under the condition of determining the presence of fractured formations in the hard rock to obtain the implementation process parameters, wherein the original process parameters include bit weight and mud viscosity;

[0008] obtaining high-frequency vibration energy and drilling speed of the barrel drill bit during drilling with the implementation process parameters to determine whether the drilling process is qualified, and if the drilling process is determined to be unqualified, determining a corresponding pressure adjustment coefficient based on the longitudinal runout amplitude of the drill pipe to increase the bit pressure, and obtaining the amount of slag returned from the sedimentation tank in real time to correct the pressure adjustment coefficient based on the slag amount fluctuation amplitude;

[0009] Obtaining an undulation curve of the barrel drill bit during the drilling process, determining whether the suction process of the drill cuttings is qualified based on the matching degree of the undulation curve with the standard curve, and increasing the suction power of the sand and gravel pump or increasing the mud viscosity based on the distribution ratio of particles with a particle size larger than a preset particle size in the returned cuttings if the suction process is unqualified;

[0010] The shape uniformity of the returned slag is obtained to determine whether the drilling process has completely entered the unfractured hard rock formation, and the implementation process parameters are restored to the original process parameters to continue drilling under the condition that it is determined that the drilling process has completely entered the unfractured hard rock formation.

[0011] Furthermore, the process of determining whether there is a fractured formation in the hard rock based on the wave velocity attenuation rate includes:

[0012] comparing the wave velocity attenuation rate with a preset attenuation rate;

[0013] Based on the comparison result that the wave velocity attenuation rate is greater than or equal to the preset attenuation rate, it is determined that there is a fractured stratum in the hard rock.

[0014] Furthermore, the process of determining whether the drilling process is qualified according to the high-frequency vibration energy and the drilling speed includes:

[0015] comparing the high-frequency vibration energy with a preset vibration energy, and comparing the drilling speed with a preset speed;

[0016] The weight on bit is determined to be unqualified based on a comparison result that the high-frequency vibration energy is greater than the preset vibration energy and the drilling speed is less than the preset speed.

[0017] Furthermore, the process of increasing the weight on bit according to the longitudinal runout amplitude includes:

[0018] Comparing the longitudinal runout amplitude with a preset runout amplitude;

[0019] Determining to increase the bit weight by a first pressure adjustment coefficient based on a comparison result that the longitudinal runout amplitude is greater than the preset runout amplitude;

[0020] Based on the comparison result that the longitudinal run-out amplitude is less than or equal to the preset run-out amplitude, it is determined to increase the bit weight by a second pressure adjustment coefficient.

[0021] Furthermore, the process of correcting the pressure adjustment coefficient according to the slag amount fluctuation amplitude includes:

[0022] Comparing the slag amount fluctuation amplitude with a preset amplitude;

[0023] Determining to adjust the pressure adjustment coefficient based on a comparison result that the slag amount fluctuation amplitude is greater than or equal to the preset amplitude;

[0024] The slag amount fluctuation amplitude is subtracted from the preset amplitude to obtain an amplitude difference, and a plurality of pressure correction coefficients corresponding to the amplitude difference are set to correct the pressure adjustment coefficient according to the pressure correction coefficients.

[0025] Furthermore, the process of determining whether the suction process of the drill cuttings is qualified according to the matching degree between the fluctuation curve and the standard curve includes:

[0026] Overlapping the undulation curve with the standard curve based on the coordinate origin;

[0027] Determining the overlapping area and the area of ​​the standard curve as a matching degree, and comparing the matching degree with a preset matching degree;

[0028] The drilling cuttings suction process is determined to be unqualified based on the comparison result that the matching degree is less than the preset matching degree.

[0029] Furthermore, under the condition that the suction process of the drill cuttings is determined to be unqualified, the process of increasing the suction power of the sand and gravel pump according to the distribution ratio of particles with a particle size larger than a preset particle size in the returned cuttings includes:

[0030] Comparing the distribution ratio with a preset distribution ratio;

[0031] determining to increase the suction power based on a comparison result that the distribution ratio is greater than or equal to the preset distribution ratio;

[0032] Subtracting the preset distribution ratio from the distribution ratio to obtain a first ratio difference;

[0033] A plurality of power adjustment coefficients corresponding to the first proportion difference are set to increase the suction power based on the power adjustment coefficients.

[0034] Furthermore, under the condition that the suction process of the drill cuttings is determined to be unqualified, the process of increasing the viscosity of the mud according to the distribution ratio of particles with a diameter greater than a preset diameter in the returned cuttings includes:

[0035] Comparing the distribution ratio with a preset distribution ratio;

[0036] determining to increase the mud viscosity based on a comparison result that the distribution ratio is less than the preset distribution ratio;

[0037] Subtracting the distribution ratio from the preset distribution ratio to obtain a second ratio difference;

[0038] A plurality of viscosity adjustment coefficients corresponding to the second ratio difference are set to increase the slurry viscosity based on the viscosity adjustment coefficients.

[0039] Furthermore, the process of determining the shape uniformity includes:

[0040] Use two-dimensional image analysis to determine the angular dispersion of any slag particles;

[0041] Counting the number of particles whose angular discreteness is greater than or equal to a preset discreteness;

[0042] The percentage of the number of the particles to the total number of the returned slag particles is determined as the shape uniformity.

[0043] Furthermore, the process of determining whether the crack-free hard rock formation has been completely entered according to the shape uniformity includes:

[0044] comparing the shape uniformity with a preset shape uniformity;

[0045] Based on the comparison result that the shape uniformity is less than the preset shape uniformity, it is determined that the formation without fractures is completely entered into.

[0046] Compared with the prior art, the beneficial effect of the present invention is that the present invention determines whether there are cracks in the formation by the wave velocity attenuation rate of ultrasound. When it is determined that there are cracks, it is necessary to adjust the drilling parameters in time to avoid the extension of the cracks due to unqualified drilling process, which leads to insufficient stability of the hole wall and the occurrence of shrinkage or collapse. When it is determined that there are cracks, the original process parameters are first adjusted according to experience, and the high-frequency vibration energy and drilling speed of the adjusted drilling process are obtained to determine whether the drilling pressure is reduced too much. If the drilling pressure is reduced too much, it will cause air grinding, which will cause electrical energy to be converted into a large amount of heat, causing abnormal wear on the drill teeth of the barrel drill, and the drilling efficiency is extremely low. Therefore, it is necessary to appropriately increase the drilling pressure. However, if the drilling pressure is increased too much, it will cause the fractured rock blocks to be fractured, causing large rock blocks to collapse, and under a large drilling pressure, the cracks will extend, which will reduce the stability of the hole wall. Therefore, the pressure adjustment coefficient is corrected according to the fluctuation amplitude of the slag amount, so as to accurately adjust the drilling pressure in the hard rock pile forming process, thereby further improving the stability of the hole wall.

[0047] Furthermore, after adjusting the drilling pressure, the present invention determines whether the suction process of the drill cuttings is qualified based on the fluctuation curve of the barrel drill. The amount of cuttings will increase in the fractured formation. Incomplete suction of the drill cuttings will cause the sediment at the bottom of the hole to be too thick, thereby exacerbating the vibration fluctuation of the barrel drill. Therefore, it is necessary to accurately adjust the suction power of the sand and gravel pump or the mud viscosity according to the matching degree of the fluctuation curve, thereby improving the operating stability of the barrel drill during the drilling process. The mud itself has a wall protection function. When it is determined that there are fractures in the formation, the mud viscosity needs to be appropriately increased. The increase in the mud viscosity is determined according to the fluctuation curve of the barrel drill. While improving the efficiency of treating the drill cuttings, it further improves the stability of the hole wall.

[0048] Furthermore, the present invention determines whether to pass through the fractured formation and enter the unfractured hard rock formation based on the shape uniformity of the returned slag particles. After determining that the formation has entered the unfractured hard rock formation, the drilling parameters are adjusted in time to avoid the drilling process being unqualified due to inappropriate drilling parameters, which in turn leads to poor hole wall stability. The present invention further improves the hole wall stability by timely and accurate adjustment of the drilling parameters. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 This is a flow chart of a rotary drilling rig construction method for hard rock pile formation according to an embodiment of the present invention;

[0050] Figure 2 A flow chart for determining whether a crack exists according to an embodiment of the present invention;

[0051] Figure 3 A flow chart showing whether a drilling process is qualified according to an embodiment of the present invention;

[0052] Figure 4 This is a flow chart showing whether the suction process of drill cuttings in an embodiment of the present invention is qualified. DETAILED DESCRIPTION

[0053] In order to make the objects and advantages of the present invention more clearly understood, the present invention is further described below in conjunction with embodiments; it should be understood that the specific embodiments described herein are merely used to explain the present invention and are not intended to limit the present invention.

[0054] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0055] See also Figure 1-Figure 4 As shown, Figure 1 This is a flow chart of a rotary drilling rig construction method for hard rock pile formation according to an embodiment of the present invention; Figure 2 A flow chart for determining whether a crack exists according to an embodiment of the present invention; Figure 3 A flow chart showing whether a drilling process is qualified according to an embodiment of the present invention; Figure 4 This is a flow chart showing whether the suction process of drill cuttings in an embodiment of the present invention is qualified.

[0056] An embodiment of the present invention provides a rotary drilling rig construction method for hard rock pile formation, comprising:

[0057] Step S1, obtaining the wave velocity attenuation rate of the ultrasonic wave during the drilling process of the rotary drilling rig to adjust the original process parameters of the pile hole under the condition of determining the presence of a fractured stratum in the hard rock to obtain the implementation process parameters, wherein the original process parameters include the bit weight and the mud viscosity;

[0058] Step S2, obtaining the high-frequency vibration energy and drilling speed of the barrel drill bit during drilling with the implementation process parameters to determine whether the drilling process is qualified, and if the drilling process is determined to be unqualified, determining a corresponding pressure adjustment coefficient based on the longitudinal runout amplitude of the drill pipe to increase the bit pressure, and obtaining the amount of slag returned from the sedimentation tank in real time to correct the pressure adjustment coefficient based on the slag amount fluctuation amplitude;

[0059] Step S3, obtaining an undulation curve of the barrel drill bit during the drilling process, determining whether the suction process of the drill cuttings is qualified based on the matching degree of the undulation curve with the standard curve, and increasing the suction power of the sand and gravel pump or increasing the mud viscosity based on the distribution ratio of particles with a particle size larger than a preset particle size in the returned cuttings if the suction process is unqualified;

[0060] Step S4, obtaining the shape uniformity of the returned slag to determine whether the drilling process has completely entered the unfractured hard rock formation, and restoring the implementation process parameters to the original process parameters to continue drilling under the condition that it is determined that the drilling process has completely entered the unfractured hard rock formation.

[0061] Specifically, the original process parameters and the implemented process parameters are in a one-to-one correspondence, including but not limited to the drill speed, bit pressure and mud viscosity.

[0062] During implementation, the present invention uses a down-the-hole drill to drill a pre-drilled hole in the center of the pile hole. The depth of the pre-drilled hole is 0.5m deeper than the pile depth. An ultrasonic receiver array is placed in the pre-drilled hole, and an ultrasonic transmitter is placed at a corresponding position in the exploration hole next to the pile hole. The difference between the exploration hole and the pre-drilled hole is no more than 3m. The diameter range of the pre-drilled hole is 110mm-130mm. The ultrasonic transmitter and the ultrasonic receiver array adjust the depth according to the drilling process. The wave velocity attenuation rate can be determined based on the transmitted wave velocity and the received wave velocity of the ultrasonic wave. When the ultrasonic wave propagates in a crack-free rock formation, it can reach 3000m / s. When encountering a crack, on the one hand, the energy of the receiving end is attenuated due to the reflected wave energy of the crack surface. On the other hand, since the wave velocity of the ultrasonic wave in the air is only 340m / s, the ultrasonic wave velocity drops sharply. Therefore, the presence of a crack can be determined based on the wave velocity attenuation rate.

[0063] Specifically, when the presence of cracks is confirmed, drilling must be stopped immediately and various parameters must be adjusted before drilling can continue. Cracks cause the instantaneous stability of the hole wall to decrease. Continuing drilling with the original process parameters will greatly increase the possibility of collapse. According to experience, the drilling pressure should be reduced to 70% of the drilling pressure in uncracked hard rock formations, the barrel drill speed should be reduced to 50% of the barrel drill speed in uncracked hard rock formations, and the mud viscosity should be increased to 1.8 times the mud viscosity in uncracked hard rock formations.

[0064] Specifically, the process of determining whether there is a fractured formation in the hard rock based on the wave velocity attenuation rate includes:

[0065] comparing the wave velocity attenuation rate with a preset attenuation rate;

[0066] Determining the presence of a fractured stratum in the hard rock based on a comparison result that the wave velocity attenuation rate is greater than or equal to the preset attenuation rate;

[0067] Based on the comparison result that the wave velocity attenuation rate is less than the preset attenuation rate, it is determined that no fractured formation exists in the hard rock.

[0068] Specifically, the preset attenuation rate is determined according to the propagation characteristics of the ultrasonic wave, and the optional range is set to [3%, 30%]. In the embodiment of the present invention, 5% is preferred.

[0069] It can be understood that the greater the wave velocity attenuation rate, the greater the opening amplitude of the crack. When the wave velocity attenuation rate is greater than 20%, the drill bit should be replaced to continue the operation. The construction process in the embodiment of the present invention is only for cracks when the wave velocity attenuation rate is greater than or equal to 5% and less than 20%. After adjusting the process parameters, the original drill bit can continue to be used for construction.

[0070] Specifically, the process of determining whether the drilling process is qualified according to the high-frequency vibration energy and the drilling speed includes:

[0071] comparing the high-frequency vibration energy with a preset vibration energy, and comparing the drilling speed with a preset speed;

[0072] Determining that the drilling process is unqualified based on a comparison result that the high-frequency vibration energy is greater than the preset vibration energy and the drilling speed is less than the preset speed;

[0073] The drilling process is determined to be qualified based on a comparison result that the high-frequency vibration energy is less than or equal to the preset vibration energy and the drilling speed is greater than or equal to the preset speed.

[0074] Specifically, the preset vibration energy and the preset speed are determined according to the drilling process of the unfractured hard rock formation. The preset vibration energy is 3 times the high-frequency vibration energy of the drilling process of the unfractured hard rock formation, and the preset speed is 0.1 times the drilling speed of the drilling process of the unfractured hard rock formation. In the embodiment of the present invention, the preset vibration energy can be 5g 2 / Hz, the preset speed can be 0.1m / h, but the above value is not limited thereto, and those skilled in the art can determine it according to actual conditions.

[0075] Specifically, the high-frequency vibration energy can be determined based on time domain and frequency domain analysis of the recording results of several three-axis acceleration sensors arranged at the power head and mast positions of the rotary drilling rig. This is a prior art and is not specifically limited. The sensor requires a sampling frequency greater than or equal to 1kHz and a range greater than or equal to 20g.

[0076] Specifically, reducing the drilling pressure when encountering cracks is to prevent rock blocks from falling, but reducing the drilling pressure too much will lead to cutting failure and cause empty grinding. This is because the shear strength of the fractured rock mass is significantly lower than that of the intact rock, but high-hardness angular bodies are retained locally. When the drilling pressure is too low, the drill teeth will slip in the soft rock area to form a sticky period, and bounce on the hard edges to form a slip period, resulting in the drill teeth being unable to wedge into the rock mass. Friction replaces cutting, causing a surge in high-frequency vibration energy and a cliff-like drop in drilling speed. Friction replacement cutting will cause a large amount of electrical energy to be converted into frictional heat energy, resulting in a surge in drill bit temperature, abnormal wear of the drill teeth, and even high temperature will cause the rock surface to recrystallize, doubling the difficulty of subsequent rock breaking.

[0077] Specifically, the process of increasing the weight on bit in a stepwise manner according to the longitudinal runout amplitude includes:

[0078] Comparing the longitudinal runout amplitude with a preset runout amplitude;

[0079] Determining to increase the bit weight by a first pressure adjustment coefficient based on a comparison result that the longitudinal runout amplitude is greater than the preset runout amplitude;

[0080] Based on the comparison result that the longitudinal run-out amplitude is less than or equal to the preset run-out amplitude, it is determined to increase the bit weight by a second pressure adjustment coefficient.

[0081] Specifically, the preset vibration amplitude is the maximum vibration amplitude when drilling in a hard rock formation without cracks, and the value range can be selected as [1.5mm, 3mm]. The embodiment of the present invention preferably uses 2mm; the value of the first pressure adjustment coefficient is determined according to engineering experience, and the value range is set to [1.07, 1.1]. The embodiment of the present invention preferably uses 1.08; the value of the second pressure adjustment coefficient is determined according to engineering experience, and the value range is set to [1.02, 1.06]. The embodiment of the present invention preferably uses 1.05.

[0082] Specifically, the adjustment process of the drilling pressure is to multiply the drilling pressure before adjustment by the corresponding pressure adjustment coefficient to obtain the drilling pressure to be achieved after adjustment.

[0083] Specifically, the process of correcting the pressure adjustment coefficient according to the slag amount fluctuation amplitude includes:

[0084] Comparing the slag amount fluctuation amplitude with a preset amplitude;

[0085] Determining to adjust the pressure adjustment coefficient based on a comparison result that the slag amount fluctuation amplitude is greater than or equal to the preset amplitude;

[0086] The slag amount fluctuation amplitude is subtracted from the preset amplitude to obtain an amplitude difference, and a plurality of pressure correction coefficients corresponding to the amplitude difference are set to correct the pressure adjustment coefficient according to the pressure correction coefficients.

[0087] It is understandable that the drilling pressure needs to be increased after the occurrence of the empty grinding phenomenon. However, if the drilling pressure is increased too much, it will lead to the fracturing of the fractured rock blocks, resulting in a sudden increase in the amount of large-scale collapse debris, an increase in the fluctuation amplitude, and will cause the hole wall to become unstable, reducing the stability of the hole. Therefore, it is necessary to appropriately reduce the drilling pressure.

[0088] Specifically, the preset amplitude is determined according to the historical construction process, and the value range is set to [70kg / m, 100kg / m]. In the embodiment of the present invention, 80kg / m is preferred.

[0089] Specifically, the slag amount refers to the mass of drill cuttings produced per meter of footage, and the slag amount fluctuation range refers to the absolute difference in the mass of drill cuttings produced per meter of footage.

[0090] Specifically, the amplitude difference is compared with a preset difference;

[0091] Determining to reduce the pressure adjustment coefficient by a first pressure correction coefficient based on a comparison result that the amplitude difference is greater than or equal to the preset difference;

[0092] Based on the comparison result that the amplitude difference is less than the preset difference, it is determined to reduce the pressure adjustment coefficient by a second pressure correction coefficient.

[0093] Specifically, the value of the preset difference is determined according to the historical construction process, and the optional range is set to [20kg / m, 60kg / m], and the embodiment of the present invention preferably prefers 30kg / m; the value of the first pressure correction coefficient is determined according to the historical construction process, and the optional range is set to [0.89, 0.92], and the embodiment of the present invention preferably prefers 0.9; the value of the second pressure correction coefficient is determined according to the historical construction process, and the optional range is set to [0.93, 0.97], and the embodiment of the present invention preferably prefers 0.94.

[0094] Specifically, the process of determining whether the suction process of drill cuttings is qualified according to the matching degree between the fluctuation curve and the standard curve includes:

[0095] Overlapping the undulation curve with the standard curve based on the coordinate origin;

[0096] Determining the overlapping area and the area of ​​the standard curve as a matching degree, and comparing the matching degree with a preset matching degree;

[0097] Determining that the suction process of the drill cuttings is unqualified based on the comparison result that the matching degree is less than the preset matching degree;

[0098] The drilling cuttings suction process is determined to be qualified based on the comparison result that the matching degree is greater than or equal to the preset matching degree.

[0099] Specifically, the fluctuation curve of the barrel drill bit is a vibration curve recorded by a three-axis acceleration sensor set on the drill rod, and the standard curve is a fluctuation curve of the barrel drill bit based on a historical drilling process with a similarity greater than 95% with the formation morphology being drilled. It can be understood that the similarity of the formation morphology is determined based on the geological exploration results, for example, it can be determined based on the crack distribution density ratio and the rock hardness ratio.

[0100] Specifically, the value of the preset matching degree is determined according to the historical drilling process, and the optional range is set to [70%, 90%]. In the embodiment of the present invention, 80% is preferred.

[0101] It is understandable that the crushing of intact rock requires overcoming the overall strength, while in fractured strata, the rock already has naturally weak fracture surfaces, and its strength is only 1 / 5-1 / 3 of the intact rock mass, making it easier to break. Compared with the amount of drill cuttings in the normal drilling process, the amount of drill cuttings produced in fractured strata will be greater, and when the drill bit cuts or impacts, the energy is preferentially transferred along the fracture surface, causing the rock to directly peel off along the fracture surface, similar to "breaking a pancake" rather than "smashing the whole piece". This crushing method will produce a large number of large-sized flaky particles peeled along the fracture surface. At the same time, the fracture tip is prone to blocky debris due to stress concentration, which will cause the particle size distribution of the drill cuttings to show that both large-sized and small-sized debris account for a large proportion. The double-peak phenomenon, the large particle size will cause the buoyancy generated by the original mud viscosity to be insufficient to float the drill cuttings to the sedimentation tank, and under the condition of increased drill cuttings, the original suction power is not enough to remove the drill cuttings in a timely and effective manner, resulting in excessive sediment at the bottom of the hole. The sediment is mainly composed of rock powder, mud and a small amount of isolated rock fragments, and its strength is much lower than that of intact rock. When the cutting edge cuts into the sediment layer, it will first crush the soft rock cuttings to produce plastic deformation, and then suddenly hit the hard isolated rock fragments to produce brittle fracture. This "soft-hard alternating" contact interface will cause the cutting force to fluctuate violently on the millisecond time scale, triggering high-frequency vibration of the drill bit, resulting in violent fluctuations in the undulation curve of the barrel drill bit.

[0102] Specifically, under the condition that the suction process of the drill cuttings is determined to be unqualified, the process of increasing the suction power of the sand and gravel pump according to the distribution ratio of particles with a particle size larger than a preset particle size in the returned cuttings includes:

[0103] Comparing the distribution ratio with a preset distribution ratio;

[0104] determining to increase the suction power based on a comparison result that the distribution ratio is greater than or equal to the preset distribution ratio;

[0105] Subtracting the preset distribution ratio from the distribution ratio to obtain a first ratio difference;

[0106] A plurality of power adjustment coefficients corresponding to the first proportion difference are set to increase the suction power based on the power adjustment coefficients.

[0107] Specifically, under the condition that the suction process of the drill cuttings is determined to be unqualified, the process of increasing the viscosity of the mud according to the distribution ratio of particles with a diameter greater than a preset diameter in the returned cuttings includes:

[0108] Comparing the distribution ratio with a preset distribution ratio;

[0109] determining to increase the mud viscosity based on a comparison result that the distribution ratio is less than the preset distribution ratio;

[0110] Subtracting the distribution ratio from the preset distribution ratio to obtain a second ratio difference;

[0111] A plurality of viscosity adjustment coefficients corresponding to the second ratio difference are set to increase the slurry viscosity based on the viscosity adjustment coefficients.

[0112] It is understandable that it is more suitable to use a reverse circulation mud system for slag removal when piling hard rock. The inlet of the sand and gravel pump is connected to the slag suction port at the bottom of the drill bit through the slurry suction pipe in the inner cavity of the drill pipe, and the outlet is connected to the sedimentation tank. The mud and rock slag enter the inner cavity of the drill pipe under the suction action of the sand and gravel pump and are discharged to the sedimentation tank through the faucet. After sedimentation and purification, they enter the slurry mixing tank and are reconfigured to flow into the pile hole for recycling.

[0113] Specifically, the sand and gravel pump can be, for example, a 6BS sand and gravel pump, which is specially designed for large-diameter pile drilling and well construction. There is no specific limitation, as long as it meets the construction requirements.

[0114] It is understandable that large-particle drill cuttings require greater buoyancy to be carried out of the pile hole and into the sedimentation tank by the mud fluid. Therefore, when the distribution ratio of large-particle size in the returned slag is relatively small, it means that the large particles in the drill cuttings are still in the pile hole and have not been carried out, and the mud viscosity needs to be increased to increase the buoyancy. When the distribution ratio of large-particle size in the returned slag is large, it means that the buoyancy generated by the mud viscosity is sufficient to make the large-particle drill cuttings flow out, but the suction power of the sand and gravel pump is insufficient, resulting in the drill cuttings being carried out too slowly, resulting in too much sediment.

[0115] Specifically, the preset particle size is determined based on experience in historical construction processes, and the value range is set to [5 mm, 10 mm]. In the embodiment of the present invention, 8 mm is preferred.

[0116] It is understood that the distribution ratio of the particle size is determined based on the analysis of the precipitated drill cuttings in the sedimentation tank.

[0117] Specifically, the value of the preset distribution ratio is determined according to the historical construction process, and the optional range is set to [25%, 40%]. In the embodiment of the present invention, 30% is preferred.

[0118] Specifically, comparing the first proportion difference with a preset difference;

[0119] determining to increase the suction power by a first power adjustment coefficient based on a comparison result that the first proportion difference is greater than the preset difference;

[0120] Based on a comparison result that the first proportion difference is less than or equal to the preset difference, it is determined to increase the suction power by a second power adjustment coefficient.

[0121] Specifically, comparing the second proportion difference with a preset difference;

[0122] determining to increase the mud viscosity by a first viscosity adjustment coefficient based on a comparison result that the second proportion difference is greater than the preset difference;

[0123] Based on the comparison result that the second proportion difference is less than or equal to the preset difference, it is determined to increase the mud viscosity by a second viscosity adjustment coefficient.

[0124] Specifically, the preset difference is determined according to the historical construction process, and the optional range is set to [3%, 7%], and the embodiment of the present invention preferably is 5%; the optional range of the first power adjustment coefficient is set to [1.4, 2], and the embodiment of the present invention preferably is 1.6; the optional range of the second power adjustment coefficient is set to [1.1, 1.5], and the embodiment of the present invention preferably is 1.3; the optional range of the first viscosity adjustment coefficient is set to [1.8, 2.5], and the embodiment of the present invention preferably is 2; the optional range of the second viscosity adjustment coefficient is set to [1.3, 1.7], and the embodiment of the present invention preferably is 1.7.

[0125] Specifically, the process of determining whether the crack-free hard rock formation has been completely penetrated based on the shape uniformity includes:

[0126] comparing the shape uniformity with a preset shape uniformity;

[0127] Determining that the entire formation has been entered into the unfractured hard rock formation based on a comparison result that the shape uniformity is less than the preset shape uniformity;

[0128] Based on the comparison result that the shape uniformity is greater than or equal to the preset shape uniformity, it is determined that the unfractured hard rock formation has not been completely entered.

[0129] Specifically, the process of determining the shape uniformity includes:

[0130] Use two-dimensional image analysis to determine the angular dispersion of any slag particles;

[0131] Counting the number of particles whose angular discreteness is greater than or equal to a preset discreteness;

[0132] The percentage of the number of the particles to the total number of the returned slag particles is determined as the shape uniformity.

[0133] Specifically, the process of determining angular dispersion using two-dimensional image analysis includes:

[0134] Spread the returned slag sample evenly on a transparent backlight plate;

[0135] Use an industrial camera to shoot high-definition images vertically, with a resolution of ≥0.1mm / pixel;

[0136] Use the Canny algorithm to perform edge detection to extract contours;

[0137] Use Harris algorithm to identify corner points and mark inner corner vertices;

[0138] Use the vector dot product to calculate the interior angles and calculate the standard deviation of the interior angles.

[0139] Specifically, the angular dispersion is the standard deviation of all internal angles of a single drill cutting particle. It can be understood that the formation of drill cuttings in unfractured hard rock formations is mainly shear crushing, with particles breaking regularly along grain boundaries, and internal angles concentrated in the range of 100°-120°, with a standard deviation range of generally 5°-10°; while the formation of drill cuttings in fractured formations is mainly due to collapse along the fractures, retaining the original acute angle of the fracture at 30°-60°, or cutting residues resulting in obtuse cross-sections of 120°-150°, with a standard deviation range of generally 25°-30°.

[0140] Specifically, the value of the preset discreteness is determined according to the historical construction process, and the optional range is set to [25°, 30°]. In the embodiment of the present invention, 25° is preferred.

[0141] Specifically, the value range of the preset shape uniformity is set to [10%, 30%], and 15% is preferred in the embodiment of the present invention.

[0142] When it is determined that the drilling process has completely entered the crack-free hard rock formation, all the implementation process parameters of the drilling process are restored to the original process parameters.

[0143] It can be understood that in the embodiment of the present invention, both return slag and drill cuttings refer to the hard rock slag generated by the rotary drilling rig during the drilling process of excavating the pile hole. The drill cuttings in the pile hole are carried out of the pile hole by the mud and flow into the sedimentation tank for sedimentation to obtain return slag.

[0144] Thus far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art may make equivalent changes or substitutions to the relevant technical features, and the technical solutions after such changes or substitutions will fall within the scope of protection of the present invention.

Claims

1. A rotary drilling rig construction method for hard rock pile formation, characterized in that: include: Obtaining a wave velocity attenuation rate of ultrasonic waves during the drilling process of the rotary drilling rig, determining whether there is a fractured formation in the hard rock based on the wave velocity attenuation rate, and adjusting original process parameters for forming the pile hole based on the presence of the fractured formation to obtain implementation process parameters, wherein the original process parameters include bit weight and mud viscosity; obtaining high-frequency vibration energy and drilling speed of the barrel drill bit during drilling with the implementation process parameters to determine whether the drilling process is qualified, and if the drilling process is determined to be unqualified, determining a corresponding pressure adjustment coefficient based on the longitudinal runout amplitude of the drill pipe to increase the bit pressure, and obtaining the amount of slag returned from the sedimentation tank in real time to correct the pressure adjustment coefficient based on the slag amount fluctuation amplitude; Obtaining an undulation curve of the barrel drill bit during the drilling process, determining whether the suction process of the drill cuttings is qualified based on the matching degree of the undulation curve with the standard curve, and increasing the suction power of the sand and gravel pump or increasing the mud viscosity based on the distribution ratio of particles with a particle size larger than a preset particle size in the returned cuttings if the suction process is unqualified; Obtaining shape uniformity of the returned slag to determine whether the drilling process has completely entered the unfractured hard rock formation, and restoring the implemented process parameters to the original process parameters to continue drilling if it is determined that the drilling process has completely entered the unfractured hard rock formation; The process of determining whether there is a fractured formation in the hard rock based on the wave velocity attenuation rate includes: comparing the wave velocity attenuation rate with a preset attenuation rate; Determining the presence of a fractured stratum in the hard rock based on a comparison result that the wave velocity attenuation rate is greater than or equal to the preset attenuation rate; The process of determining whether the drilling process is qualified according to the high-frequency vibration energy and the drilling speed includes: comparing the high-frequency vibration energy with a preset vibration energy, and comparing the drilling speed with a preset speed; Determining that the drilling process is unqualified based on a comparison result that the high-frequency vibration energy is greater than the preset vibration energy and the drilling speed is less than the preset speed; The process of increasing the bit weight according to the longitudinal runout amplitude includes: Comparing the longitudinal runout amplitude with a preset runout amplitude; Determining to increase the bit weight by a first pressure adjustment coefficient based on a comparison result that the longitudinal runout amplitude is greater than the preset runout amplitude; Determining to increase the bit weight by a second pressure adjustment coefficient based on a comparison result that the longitudinal runout amplitude is less than or equal to the preset runout amplitude; The process of correcting the pressure adjustment coefficient according to the slag amount fluctuation amplitude includes: Comparing the slag amount fluctuation amplitude with a preset amplitude; Determining to adjust the pressure adjustment coefficient based on a comparison result that the slag amount fluctuation amplitude is greater than or equal to the preset amplitude; The slag amount fluctuation amplitude is subtracted from the preset amplitude to obtain an amplitude difference, and a plurality of pressure correction coefficients corresponding to the amplitude difference are set to correct the pressure adjustment coefficient according to the pressure correction coefficients.

2. The rotary drilling rig construction method for hard rock pile formation according to claim 1, characterized in that: The process of determining whether the drilling cuttings suction process is qualified according to the matching degree between the fluctuation curve and the standard curve includes: Overlapping the undulation curve with the standard curve based on the coordinate origin; Determining the percentage of the overlapping area and the area of ​​the standard curve as a matching degree, and comparing the matching degree with a preset matching degree; The drilling cuttings suction process is determined to be unqualified based on the comparison result that the matching degree is less than the preset matching degree.

3. The rotary drilling rig construction method for hard rock pile formation according to claim 2, characterized in that: Under the condition that the suction process of the drill cuttings is determined to be unqualified, the process of increasing the suction power of the sand and gravel pump according to the distribution ratio of particles with a diameter larger than a preset diameter in the returned cuttings includes: Comparing the distribution ratio with a preset distribution ratio; determining to increase the suction power based on a comparison result that the distribution ratio is greater than or equal to the preset distribution ratio; Subtracting the preset distribution ratio from the distribution ratio to obtain a first ratio difference; A plurality of power adjustment coefficients corresponding to the first proportion difference are set to increase the suction power based on the power adjustment coefficients.

4. The rotary drilling rig construction method for hard rock pile construction according to claim 3, characterized in that: Under the condition that the suction process of the drill cuttings is determined to be unqualified, the process of increasing the viscosity of the mud according to the distribution ratio of particles with a diameter greater than a preset diameter in the returned cuttings includes: Comparing the distribution ratio with a preset distribution ratio; determining to increase the mud viscosity based on a comparison result that the distribution ratio is less than the preset distribution ratio; Subtracting the distribution ratio from the preset distribution ratio to obtain a second ratio difference; A plurality of viscosity adjustment coefficients corresponding to the second ratio difference are set to increase the slurry viscosity based on the viscosity adjustment coefficients.

5. The rotary drilling rig construction method for hard rock pile construction according to claim 4, characterized in that: The process of determining the shape uniformity includes: Use two-dimensional image analysis to determine the angular dispersion of any slag particles; Counting the number of particles whose angular discreteness is greater than or equal to a preset discreteness; The percentage of the number of the particles to the total number of the returned slag particles is determined as the shape uniformity.

6. The rotary drilling rig construction method for hard rock pile construction according to claim 5, characterized in that: The process of determining whether the unfractured hard rock formation has been completely penetrated based on the shape uniformity includes: comparing the shape uniformity with a preset shape uniformity; Based on the comparison result that the shape uniformity is less than the preset shape uniformity, it is determined that the formation has entered a crack-free hard rock formation.

Images