A method for testing the vibration acceleration of drilling in sandstone caves.

Abstract

This invention relates to a method for testing the vibration acceleration of drilling in sandstone cave rock masses. The method includes the following steps: (1) Vertically setting several equally spaced drilling points at locations with nearly identical lithology in the sandstone cave rock mass; (2) On a vertically flat rock mass, sequentially arranging several acceleration sensors at varying intervals along the same side of the longitudinal direction at each drilling point; (3) Marking and arranging the acceleration sensors and their attachment positions, organizing the data leads, and using a reinforcing liquid for spray reinforcement; (4) After reinforcement, attaching the acceleration sensors to the surface of the rock mass, and connecting the acceleration sensor leads to a data acquisition instrument after the adhesion is firm; (5) Drilling holes sequentially at the drilling points using drilling equipment and collecting the corresponding vibration acceleration data; (6) Plotting the obtained vibration acceleration data into a graph to determine the influence range and attenuation characteristics of the drilling vibration wave. This invention is simple to operate and highly adaptable.

Description

Technical Field

[0001] This invention relates to the field of reinforcement and protection technology for rock masses containing grottoes, and in particular to a method for testing the vibration acceleration of drilling into sandstone grotto rock masses. Background Technology

[0002] Stone cultural relics are a unique part of my country's historical and cultural heritage. Grottoes and temples embody and record various aspects of the Chinese nation's development over five thousand years, containing immense historical and artistic value. my country's grottoes are widely and concentrated, with a long history. As of the eighth batch of national key cultural relics protection units announced so far, there are a total of 5,058 sites, including 283 grottoes and stone carvings, distributed across all provinces and cities in China. Sandstone grottoes account for approximately 80% of the total number of grottoes in the country. Solving the engineering and technical challenges faced by sandstone grottoes can provide guidance for the reinforcement projects of various types of grottoes in my country.

[0003] Grotto temples are massive and immovable, often situated in open or semi-open environments. Long-term exposure to the external environment leads to frequent damage, with cliff face cracking, instability, and collapse being one common occurrence. There are various methods for reinforcing collapsed rock masses in grottoes, commonly employing methods such as direct support with stone blocks, chemical grouting, steel beam ceiling reinforcement, and anchor bolt fixation. Among these, anchor bolt fixation technology, characterized by low disturbance, high concealment, and high anchoring force, is widely used in grotto rock mass reinforcement projects.

[0004] Rock mass anchoring technology requires drilling into the rock mass, and the drilling vibrations during anchoring inevitably affect the cultural relics in the grottoes. Current research on the impact of vibration waves on grotto cultural relics mainly focuses on the reinforcement of unstable rock masses in grotto cliffs. Research findings such as low-speed drilling, low-wind-pressure drilling, and spiral drilling are instructive for rock mass reinforcement projects. However, these anchoring projects are limited to large unstable rock masses around grottoes, and there is still a certain distance between the anchor bolts and the rock mass of the grottoes. These findings are significantly different from drilling into the grotto roof itself. Therefore, based on current research findings, it is necessary to conduct a detailed study on the impact range of drilling vibrations on sandstone grotto rock masses, as well as the attenuation characteristics of vibration waves at different regions and depths, to optimize drilling techniques and protective measures, and ensure the safety of the reinforcement project. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a simple and adaptable method for testing the vibration acceleration of drilling in sandstone caves.

[0006] To address the above problems, the present invention provides a method for testing the vibration acceleration of a sandstone cave borehole, comprising the following steps:

[0007] (1) Several equally spaced boreholes were vertically set at locations on the sandstone cave rock mass where the strata lithology was nearly identical;

[0008] (2) On the vertically flat rock mass, several acceleration sensors with unequal spacing are sequentially arranged on the same side of the longitudinal direction along the position of each of the drilling points;

[0009] (3) Mark and arrange the accelerometer and the pasting position, organize the data wires, and use reinforcement liquid to spray and reinforce the square area around the pasting position;

[0010] (4) After reinforcement is completed, prepare grout and attach the accelerometer to the surface of the rock mass. After the adhesion is firm, connect the wires of the accelerometer to the data acquisition instrument.

[0011] (5) Drill holes sequentially at the drilling points using drilling tools. At this time, the data acquisition instrument collects the vibration acceleration data of the corresponding acceleration sensor, and the single acquisition time is not less than 15 minutes.

[0012] ⑹ By plotting the obtained vibration acceleration data into a chart, the influence range and attenuation characteristics of the construction borehole vibration wave can be determined.

[0013] The number of drilling points in step (1) is 6.

[0014] In step (2), there are 15 accelerometers, and the distance between the first accelerometer closest to each drilling point is no more than 20 mm; the distance between the first to fifth accelerometers is no more than 20 mm; the distance between the sixth to tenth accelerometers is no more than 50 to 200 mm; and the distance between the eleventh to fifteenth accelerometers is no more than 50 to 200 mm.

[0015] The method for determining the influence range and attenuation characteristics of the construction borehole vibration wave in step (6) is as follows: plot the vibration acceleration data obtained from a borehole and all accelerometers arranged laterally into a chart, determine the influence range of the construction borehole vibration wave by the position where the data of the farthest sensor is close to zero, and determine the attenuation characteristics of the construction borehole vibration wave by plotting the data obtained from the borehole and all accelerometers arranged laterally.

[0016] Compared with the prior art, the present invention has the following advantages:

[0017] 1. This invention involves deploying acceleration sensors on the surface of the rock mass and obtaining the vibration acceleration at various measuring points at different distances from the borehole location using a data acquisition instrument. Based on the acceleration data of the rock surface, appropriate drilling parameters are adopted to optimize the drilling process and protective measures, thereby maximizing the protection of grotto cultural relics and the safety of construction personnel.

[0018] 2. Based on the data of surface acceleration changes in the rock mass of the grotto, this invention can assess the depth and range of the influence of drilling parameters on the rock mass of the grotto, as well as the attenuation characteristics of vibration waves, providing a basis for the scientific and rational reinforcement of the rock mass of the grotto.

[0019] 3. This invention is simple to operate, can continuously collect data, and has a wide range of acceleration measurements. It is not only convenient to use but also highly applicable. It is suitable for testing the surface acceleration of rock masses under various types of conditions and is of great significance for the reinforcement of rock masses in grottoes. Attached Figure Description

[0020] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0021] Figure 1 This is a schematic diagram of the present invention.

[0022] Figure 2 This is a schematic diagram of the accelerometer sensor layout in this invention.

[0023] In the diagram: 1—drilling point; 2—accelerometer; 3—data acquisition instrument; 4—rock mass. Detailed Implementation

[0024] like Figure 1 As shown, a method for testing the vibration acceleration of a sandstone cave borehole includes the following steps:

[0025] (1) Several equally spaced boreholes 1 are vertically set at locations on the sandstone cave rock mass 4 where the strata lithology is nearly identical. The preferred number of boreholes 1 is 6.

[0026] (2) On the vertically flat rock mass 4, several acceleration sensors 2 with different spacings are arranged sequentially on the same side of the longitudinal direction along the position of each drilling point 1.

[0027] The preferred number of accelerometers 2 is 15, with the spacing between the first accelerometer closest to each drilling point 1 and no greater than 20 mm; the spacing between the first to fifth accelerometers and no greater than 20 mm; the spacing between the sixth to tenth accelerometers and no greater than 50 to 200 mm; and the spacing between the eleventh to fifteenth accelerometers and no greater than 50 to 200 mm. The approximate range of vibration acceleration influence is determined by gradually increasing the spacing between 1 to 10 accelerometers, and then the range of vibration acceleration influence is refined by gradually decreasing the spacing between 11 to 15 accelerometers.

[0028] If the data from the last accelerometer does not decrease significantly after the above tests, the spacing between the accelerometers 2 can be gradually increased according to the above rules.

[0029] (3) Mark the accelerometer 2 and the pasting position and arrange them neatly. Organize the data wires and use reinforcement liquid to spray and reinforce the square area with a length of 4-6cm around the pasting position.

[0030] The reinforcement solution can be a 1.5% (w / w) silicone-modified acrylic solution or a 3% (w / w) sandstone reinforcement material (which needs to be diluted with a special diluent).

[0031] (4) After reinforcement is completed, prepare grout and attach the accelerometer 2 to the surface of the rock mass 4. After the adhesion is firm, connect the wire of the accelerometer 2 to the data acquisition instrument 3.

[0032] Slurry refers to a slurry with a water-cement ratio of 0.2, prepared by mixing calcined boulders and sandstone powder in a 1:1 weight ratio (g / g) and then adding water.

[0033] (5) Drilling is performed at drilling point 1 using a drilling tool. At this time, the data acquisition instrument 3 collects the vibration acceleration data of the corresponding acceleration sensor 2. The single acquisition time is not less than 15 minutes.

[0034] (6) By plotting the obtained vibration acceleration data into a graph, the influence range and attenuation characteristics of the drilling vibration wave can be determined. The specific process is as follows:

[0035] The vibration acceleration data obtained from a borehole and all the accelerometers 2 arranged laterally are plotted into a graph. The influence range of the construction borehole vibration wave is determined by the position where the data of the farthest sensor is close to zero. The attenuation characteristics of the construction borehole vibration wave are determined by the graph plotted with the data obtained from this borehole and all the accelerometers 2 arranged laterally.

[0036] [Working Principle] This invention uses acceleration sensors with different distance gradients to collect acceleration data at a certain location during drilling. The analysis of the influence range and attenuation of vibration waves is carried out by analyzing the acceleration data collected during drilling. The purpose of drilling multiple times is to obtain the above data through this test, and finally determine the result through one or more data sets. Example

[0037] A method for testing the vibration acceleration of a sandstone cave borehole includes the following steps:

[0038] (1) Vertically set up borehole point 1 at a location on the sandstone cave rock mass 4 where the strata lithology is almost the same.

[0039] One is set every 50mm along the vertical direction, namely point A, point B, point C, point D, point E, and point F.

[0040] (2) For example Figure 2As shown, 15 accelerometers 2 are arranged along each drilling point 1 to one side. In the first test, the distance between the first accelerometer and the drilling point on one side of drilling point 1 is no more than 20mm, the distance between the first to fifth accelerometers is no more than 20mm, the distance between the sixth to tenth accelerometers is no more than 50mm, and the distance between the eleventh to fifteenth accelerometers is no more than 100mm.

[0041] (3) If the data of the 15th accelerometer does not decrease significantly after the first test, the second test will be adjusted so that the distance between the first accelerometer and the drilling point on one side of the drilling point B is no more than 20mm, the distance between the first to fifth accelerometers is no more than 20mm, the distance between the sixth to tenth accelerometers is no more than 50mm, and the distance between the eleventh to fifteenth accelerometers is no more than 200mm.

[0042] For the third test, the distance between the first accelerometer and the drilling point on one side of drilling point C is no more than 20mm, the distance between the first to fifth accelerometers is no more than 20mm, the distance between the sixth to tenth accelerometers is no more than 100mm, and the distance between the eleventh to fifteenth accelerometers is no more than 200mm.

[0043] (4) If the data from the 15th accelerometer is significantly lower than that from the first three accelerometers after the second and third tests, the fourth test will be adjusted so that the distance between the first accelerometer and the drilling point on one side of drilling point D is no more than 20mm, the distance between the first to fifth accelerometers is no more than 50mm, the distance between the sixth to tenth accelerometers is no more than 200mm, and the distance between the eleventh to fifteenth accelerometers is no more than 50mm.

[0044] For the fifth test, the distance between the first accelerometer and the drilling point on one side of drilling point E is no more than 20mm, the distance between the first to fifth accelerometers is no more than 20mm, the distance between the sixth to tenth accelerometers is no more than 200mm, and the distance between the eleventh to fifteenth accelerometers is no more than 100mm.

[0045] (5) If the data from the 15th accelerometer does not decrease significantly after the fourth and fifth tests, the spacing between the accelerometers can be gradually increased according to the above rules. The core is to determine the approximate range of vibration acceleration by gradually increasing the spacing between the 1st to 10th accelerometers, and then refine the test range of vibration acceleration by gradually decreasing the spacing between the 11th to 15th accelerometers.

[0046] (6) When the acceleration data measured by the sensor farthest from the drilling point is close to zero or zero, the influence range of the drilling vibration can be determined by the distance from the farthest point to the drilling point at this time. At this time, the test can be ended without further adjustment. The attenuation degree at different distances can be analyzed using this data.

[0047] After marking the positions of accelerometer 2, mark the accelerometer 2 and arrange them neatly in order, and tidy up the sensor wires. Use a 1.5% organosilicon-modified acrylic acid solution to spray and reinforce the surface of rock mass 4 at predetermined locations.

[0048] (7) One hour after reinforcement is completed, prepare a slurry using calcined boulders and sandstone powder in a 1:1 ratio with a water-cement ratio of 0.2. Adhere the accelerometer 2 to the surface of the rock mass 4. After at least 3 hours, the accelerometer 2 should be fully fixed. Once the sensor is firmly bonded, connect the wires of the accelerometer 2 to the data acquisition instrument 3.

[0049] (8) Drill a hole at drilling point 1 using a drilling tool. The data acquisition instrument 3 collects the vibration acceleration data of the acceleration sensor 2. The single acquisition time is not less than 15 minutes.

[0050] The purpose of drilling at different points is to obtain the influence range and attenuation rate of the drilling vibration wave through multiple tests, and ultimately to clarify the boundary of the vibration influence.

[0051] (9) After the first test is completed, remove the accelerometer 2, wipe the surface and connection clean, and reposition it to the sensor measurement point position for the next test. Repeat the above operation. When the data of the 15th accelerometer is close to zero or zero, the test is considered to be over. Plot the vibration acceleration data at these measurement points into a graph to finally determine the influence range and attenuation characteristics of the construction borehole vibration wave.

Claims

1. A method for testing the vibration acceleration of a sandstone cave borehole, comprising the following steps: Step 1: Vertically set several equally spaced boreholes (1) at locations on the sandstone cave rock mass (4) where the strata lithology is nearly the same; Step (2): On the vertically flat rock mass (4), several accelerometers (2) with varying spacing are sequentially arranged on the same side along the longitudinal direction of each drilling point (1); the number of accelerometers (2) is 15, and the spacing between the first accelerometer closest to each drilling point (1) is no greater than 20mm; the spacing between the first to fifth accelerometers is no greater than 20mm; the spacing between the sixth to tenth accelerometers is no greater than 50 to 200mm; the spacing between the eleventh to fifteenth accelerometers is no greater than 50 to 200mm. Step (3): Mark and arrange the accelerometer (2) and the pasting position, organize the data wires, and use reinforcement liquid to spray and reinforce the square area around the pasting position; Step 4: After the reinforcement is completed, prepare grout and stick the acceleration sensor (2) to the surface of the rock mass (4). After the adhesion is firm, connect the wire of the acceleration sensor (2) to the data acquisition instrument (3). Step 5: Drill a hole at the drilling point (1) using a drilling tool. At this time, the data acquisition instrument (3) collects the vibration acceleration data of the corresponding acceleration sensor (2). The single acquisition time is not less than 15 minutes. If the data of the 15th acceleration sensor does not decrease significantly after the test, the approximate vibration acceleration influence range is determined by gradually increasing the distance between the 1st to 10th acceleration sensors. Then, the vibration acceleration influence range is refined by gradually decreasing the distance between the 11th to 15th acceleration sensors. Step 6: Plot the obtained data into a chart to determine the influence range and attenuation characteristics of the construction borehole vibration wave; the method for determining the influence range and attenuation characteristics of the construction borehole vibration wave is as follows: plot the vibration acceleration data obtained by a borehole and all accelerometers (2) arranged laterally into a chart, determine the influence range of the construction borehole vibration wave by the position when the data of the farthest sensor is close to zero, and determine the attenuation characteristics of the construction borehole vibration wave by plotting the data obtained by the borehole and all accelerometers (2) arranged laterally.

2. The method for testing the vibration acceleration of a sandstone cave borehole as described in claim 1, characterized in that: The number of drilling points (1) in step (1) is 6.

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