CN116044374A - Mountain area underground engineering mouth geological survey method and plugging device - Google Patents

Abstract

The invention discloses a geological survey method for a mountain area underground engineering mouth, which comprises the following steps: carrying out geological investigation on the position of the mouth of the underground engineering and the area nearby the position; drilling a horizontal hole; sealing the front end of the drill rod, and feeding the cable provided with a plurality of detectors into the drill rod; placing the drill rod into the horizontal hole; filling water into the drill rod, and plugging the rear end of the drill rod; connecting a cable with a seismic wave prospecting instrument, starting the seismic wave prospecting instrument, arranging shot points, firing by adopting a large hammer source at the shot points, and collecting seismic wave data; forming an engineering geological map. The invention also discloses a plugging device applied to the method. The geological survey method and the plugging device for the mountain area underground engineering mouth are not limited by terrain, the survey process is little influenced by external environment, the noise level is low, the survey result is reliable, the working efficiency is high, and the survey cost is saved; the plugging device has the advantages of simple structure, convenient setting, more accurate survey result and higher precision.

Description

Mountain area underground engineering mouth geological survey method and plugging device

Technical Field

The invention relates to the field of geological survey, in particular to a surveying method and a plugging device for the geological condition of a mouth of a mountain area underground project.

Background

For mountain special underground engineering, the surveying result of engineering mouth geology has very important significance and effect on engineering protection, structural design, engineering construction and other aspects. Many surveying methods for the geological area of the mouth, such as seismic refraction, high density electrical methods, etc., but these geophysical prospecting methods have high requirements on the terrain, and can generally only be applied to the terrain condition that the mountain gradient is less than 30 degrees.

When the gradient of the mountain is larger than 30 degrees, because the seismic wave refraction method and the high-density electrical method are both required to lay cables and insert electrodes on the mountain, the workload is large, the efficiency is low, the noise is large, the signals are poor when the mountain is in windy weather, the water-containing low-resistance body is arranged on the ground surface when the mountain is in rainy weather, the false abnormality of the electrical method geophysical prospecting can be caused, the application effect is poor, and therefore the conventional geophysical prospecting method cannot be used normally. In this case, the engineering geology of the borehole to the surface can generally only be inferred from the horizontal borehole and the simple ground tuning results. In most cases, the slope feet of mountain areas are covered with a layer, and effective geology is not too much exposed, so that the surveying method only by horizontal drilling and 'one hole' can lead to low accuracy of geological surveying results of mouth engineering, has large inferred components and is difficult to meet geological requirements of engineering mouth design construction.

Disclosure of Invention

The invention provides a geological survey method and a plugging device for a mountain area underground engineering mouth, which can be free from the limitation of terrain, and has the advantages of little influence by external environment, high working efficiency and low investigation cost. The specific technical scheme is as follows:

a geological survey method for a mountain area underground engineering mouth comprises the following steps:

determining the position of a mouth of an underground project, and carrying out geological investigation of the position of the mouth and the nearby area;

drilling a horizontal hole into the mountain along the horizontal direction at the position of the engineering opening, and recording the drilling;

selecting a drill rod according to the size of the horizontal hole, sealing the front end of the drill rod extending into the horizontal hole, and feeding a cable provided with a plurality of detectors into the drill rod;

placing the drill rod provided with the cable and the detector into the horizontal hole until the cable and the detector are pushed to the position to be detected;

injecting water into the drill rod from the rear end of the drill rod close to the engineering opening, filling water into the drill rod, and then plugging the rear end of the drill rod;

connecting a cable with a seismic wave prospecting instrument, starting the seismic wave prospecting instrument, arranging shot points on the ground surface above the horizontal hole, and firing by adopting a large hammer source at the position of the shot points to enable a wave detector in a drill rod to acquire seismic wave data of each channel;

and forming an engineering geological map according to the collected seismic wave data.

Further, when the horizontal hole is drilled, the drilling direction is inclined downward in the horizontal direction, and the inclination angle is 2 degrees to 5 degrees.

Further, the plugging device is used for plugging the rear end of the drill rod, the plugging device is provided with a water injection hole, the water injection hole is communicated with the inner space of the drill rod, and water is injected into the drill rod through the water injection hole.

Further, a cable channel is arranged in the plugging device, and a cable arranged in the drill rod passes through the cable channel and out of the plugging device so as to be connected with the seismic prospecting instrument.

Further, the cable is in sealing connection with the cable channel to prevent water in the drill rod from flowing out of the drill rod through the cable channel.

Further, the plugging device comprises an expandable outer wall, an expansion chamber is arranged in the plugging device, before water is injected into the drill rod, fluid is injected into the expansion chamber, the pressure in the expansion chamber is increased, the outer wall is expanded outwards along the radial direction of the plugging device, and the outer wall is fixed in contact with the inner wall of the drill hole.

Further, the fluid filled into the expansion chamber is water to enhance the coupling effect of the geophone.

Further, two or more shot points can be arranged at two or more positions, and the large hammer focus is adopted to fire at the two or more shot point positions respectively, so that seismic wave data acquisition of each channel is repeatedly carried out; before an engineering geological map is formed, inversion calculation is carried out on collected seismic wave data by utilizing seismic tomography inversion software, a longitudinal wave velocity distribution map of a stratum between a shot point and a detector is obtained, and a test result is verified compared with a rock mass wave velocity curve result of an in-hole logging test.

The plugging device is applied to the mountain area underground engineering mouth geological survey method, and comprises a device body, wherein one end of the device body is in sealing connection with a drill rod, the other end of the device body extends in a direction away from the drill rod, a water injection channel and a cable channel are arranged in the device body, the water injection channel and the cable channel are communicated with an inner cavity of the drill rod, water flows into the inner cavity of the drill rod through the water injection channel, and a cable in the drill rod extends out of the drill rod through the cable channel; the surface of the device body is provided with an annular outer wall, an expansion chamber is arranged in the device body and is arranged close to the outer wall, the outer wall is an expandable outer wall with elastic contraction capacity, and the expandable outer wall can expand or contract along with the increase and decrease of the pressure in the expansion chamber; the cable channel and the water injection channel are arranged in the middle of the device body, and the expansion chamber and the expandable outer wall are arranged outside the cable channel and the water injection channel in a surrounding mode.

Further, the first end of cable channel and the inside cavity intercommunication setting of drilling rod, the second end extends the setting towards the direction of keeping away from the drilling rod, and the cable in the drilling rod stretches into from cable channel's first end, wears out by cable channel's second end, and cable channel's first end and second end department are provided with seal structure, and seal structure sets up between cable channel's inner wall and cable's outer wall.

The geological survey method and the plugging device for the mountain area underground engineering mouth have the following advantages:

1. is not limited by the terrain, and is also applicable to the terrain environment with the mountain gradient of more than 30 degrees;

2. the surveying process is less influenced by external environment, the noise level is low, the surveying result is more reliable, and accurate geological information can be provided for the mouth structure and the protection design;

3. the cable and the sensor are not required to be paved on the surface of the mountain, so that the working efficiency is high, and the operation is convenient;

4. the inherent drilling structure in the survey process is fully utilized, the utilization rate of drilling is improved, and the survey cost is saved;

5. the plugging device has the advantages of simple structure, convenient setting, more accurate survey result and higher precision.

Drawings

Fig. 1 is a cross-sectional view of an occluding device in accordance with the present invention.

Fig. 2 is a second cross-sectional view of the occluding device of the present invention.

FIG. 3 is a schematic layout of a seismic survey.

FIG. 4 is a graph of the longitudinal wave velocity profile of the formation between the shot and the geophone calculated using the seismic tomography inversion software.

FIG. 5 is a graph of longitudinal wave velocities for in-hole logs 28m-39m.

Fig. 6 is a geological interpretation.

Detailed Description

In order to better understand the purpose, structure and function of the present invention, the geological survey method and plugging device for the mountain area underground engineering mouth of the present invention will be described in further detail below with reference to the accompanying drawings.

The geological survey method for the mountain area underground engineering mouth part comprises the following steps:

1. geological survey

Determining the position of a mouth of an underground project, collecting geological data of the mouth of the project, and carrying out geological investigation of the position of the mouth and the nearby area. Specifically, geological investigation and recording are performed on the formation lithology, the distribution of the slope masses, the outcrop condition of the rock, the occurrence of main fracture, the weathering degree and the like near the mouth and at the upper part of the mouth.

2. Drilling horizontal hole

And a horizontal hole is drilled in the mountain along the horizontal direction at the engineering opening position, and the length of the horizontal hole is generally 70-200 m. Preferably, the length of the horizontal hole is 100M.

When the horizontal hole is drilled, the drilling direction is slightly inclined downwards along the horizontal direction, and the inclination angle is 2-5 degrees. By adopting the angle inclined drilling horizontal hole, water can be prevented from flowing out of the drill rod along the horizontal direction in the injection process when water is injected into the drill rod in the subsequent step, and the water injection efficiency and effect are affected.

A detailed borehole record is made during horizontal hole drilling. Specifically, parameters of a drilling machine, backwater conditions, rock properties of a core, fracture occurrence, weathering degree, core length and the like in the drilling process are recorded.

3. Setting drill rod and wave detector

Selecting a drill rod according to the size of the horizontal hole, and sealing the front end of the drill rod which is to extend into the horizontal hole, so that the front end of the drill rod is sealed; feeding a cable provided with a plurality of detectors into the drill rod; and the rear end of the drill rod close to the engineering opening is plugged by using a plugging device, so that the rear end of the drill rod is sealed.

4. Placing the drill rod into the horizontal hole

And placing the well-arranged drill rod and the detector into the horizontal hole until the cable and the detector are pushed to the designated detection position.

5. Water is injected into the drill pipe

The plugging device is provided with a water injection hole which is communicated with the inner space of the drill rod, and a water pipe or other water-injecting devices are connected with the water injection hole, so that the drill rod is filled with water. The water is a coupling agent between the vibration and the detectors, so that the string detectors in the drill rod can exert better working effects, and the accuracy of the survey results is improved.

6. Performing seismic wave exploration

Connecting a cable in a drill rod with a seismic wave prospecting instrument host, selecting a shot point layout position on the ground surface above a horizontal hole, and arranging a shot point I; and firing by adopting a large hammer focus at a position of the shot point, and enabling a detector in the drill rod to acquire seismic wave data of each channel.

Preferably, the plugging device is provided with a cable channel, the cable in the drill rod extends out of the plugging device through the cable channel and is connected with the seismic prospecting instrument host, and the cable is in sealing connection with the cable channel so as to prevent water injected into the drill rod from flowing out along the cable channel.

7. Selecting new shot point position, repeatedly making seismic wave exploration

And (3) arranging a second shot point at a position spaced by a plurality of meters along the extending direction of the horizontal hole, repeating the operation process of the step (6), firing by adopting a large hammer focus at the second shot point, and enabling a detector in the drill rod to acquire seismic wave data of each channel.

Preferably, according to the exploration requirement, two or more positions can be selected to be provided with shot points, and seismic wave data acquisition is repeatedly carried out.

8. Forming engineering geological map

Processing the collected seismic wave data by using a cross-hole tomography inversion software, calculating a rock-soil mass longitudinal wave velocity contour map from a horizontal hole to the earth surface, and combining drilling records and earth surface land adjustment results to obtain an oral engineering geological longitudinal section map; and comprehensively analyzing result data of each investigation method, writing geotechnical engineering investigation reports, and finishing engineering geological maps.

Specifically, as shown in fig. 1 and 2, the plugging device in the above steps 4 to 6 has one end connected with the drill rod 1 in a sealing manner, and the other end extending toward the mouth position of the project. The plugging device comprises an outer wall 2, wherein the outer wall 2 is annular, the annular outer wall 2 encloses into a cylindrical plug structure, and a containing space is formed in the outer wall 2. A water injection channel 3 is arranged in the accommodating space, a first end of the water injection channel 3 is communicated with the internal cavity of the drill rod 1, and a second end extends towards the opening position of the project; the water flow is injected from the second end of the water injection channel 3 and flows into the drill rod 1 through the first end of the water injection channel 3, so that the drill rod 1 is filled with water, the coupling effect of the detector in the drill rod 1 is improved, and the accuracy and precision of the detection result are improved.

Preferably, the second end of the water injection channel 3 is provided with a water injection joint 31, and the water injection joint 31 protrudes from the accommodating space surrounded by the outer wall 2, so as to be stably connected with a water pipe or other water injection devices, thereby improving water injection efficiency.

Further, a cable channel 4 is arranged in the receiving space, the cable channel 4 preferably being arranged parallel to the water injection channel 3. The first end of the cable channel 4 is communicated with the internal cavity of the drill rod 1, and the second end extends towards the mouth part of the project; a cable 12 with a plurality of detectors 11 is located in the drill rod 1, the end of which extends into the cable channel 4 from a first end and out of the plugging device through a second end of the cable channel 4 for connection to a host of the seismic survey. Sealing structures 41 such as sealing gaskets and sealing glue are arranged at the first end and the second end of the cable channel 4, the sealing structures 41 are arranged between the inner wall of the cable channel 4 and the outer wall of the cable 12, and water filled in the drill rod 1 can be prevented from flowing out of the drill rod 1 through the cable channel 4.

Further, an expansion chamber 5 is arranged in the accommodating space, and the expansion chamber 5 is in a ring shape as a whole and is arranged against the outer wall 2 of the plugging device; the outer wall 2 of the plugging device is an expandable outer wall 2, is made of elastic materials such as rubber and silica gel, preferably silica gel, has good elastic shrinkage capacity, and when the expansion chamber 5 is filled with enough water or gas and other fluid, the pressure in the expansion chamber 5 is increased, so that the outer wall 2 expands outwards along the radial direction of the plugging device, the outer wall 2 is fully contacted with the inner wall of a drilled hole, and the effect of positioning and fixing is achieved. After the test is finished, the pressure in the expansion chamber 5 is removed, so that the outer wall 2 is separated from the inner wall of the drill hole, and the plugging device and the drill rod 1 are taken out of the drill hole.

The expansion chamber 5 is provided with a connection port 51, and the connection port 51 is preferably arranged on one side of the plugging device close to the engineering mouth part, so as to be connected with a water filling or inflating device, and fluid such as water or gas is filled into the expansion chamber 5. Preferably, the fluid filled into the expansion chamber 5 is water to enhance the coupling effect of the cable 12 and the pickup 11.

Preferably, an elongated connection channel is provided between the connection port 51 and the expansion chamber 5, and the connection port 51 communicates with the expansion chamber 5 through the connection channel. The elongate connecting channel increases the resistance to fluid flow and helps to maintain the pressure within the expansion chamber 5, providing a stable connection between the expansion chamber 5 and the expandable outer wall 2 and the inner wall of the borehole.

Preferably, the cable passage 4 and the water filling passage 3 are arranged in the middle of the plugging device accommodation space, and the expansion chamber 5 and the expandable outer wall 2 are arranged around the outside of the cable passage 4 and the water filling passage 3.

Preferably, the end of the plugging device connected with the drill rod 1 is provided with an extension part 6, the extension part 6 extends 5 into the drill rod 1 and is attached to the inner wall of the drill rod 1 so as to improve the plugging device and the drill rod 1

Sealing connection effect between the two.

The method for using the plugging device and the working flow are specifically described below with reference to the specific steps of the geological survey method for the mountain area underground engineering mouth.

As shown in fig. 2, in the operation of step 3 of the above-mentioned mountain area underground works mouth geological survey method, 0 the drill pipe 1 with the plugging device installed has pushed the cable 12 and the geophone 11 to the test site, and is electrically operated

The cable 12 extends out of the plugging device from the interior of the drill rod 1 through the cable channel 4, and the cable 12 is in sealing connection with the cable channel 4 through a sealing structure 41;

connecting the cable 12 with a host of the seismic prospecting instrument, connecting the first water injection pipeline with the water injection joint 31 of the water injection channel 3, and connecting the second water injection pipeline with the connection port 51 of the expansion chamber 5; 5, injecting water into the expansion chamber 5 through a second water injection pipeline to expand the expandable outer wall 2 and fully contact with the inner wall of the drilled hole; the second water injection pipeline is provided with a pressure test pump, and the water injection action of the second water injection pipeline can be stopped when the pressure of the pressure test pump reaches 0.4-0.6 MPa in general;

after the expandable outer wall 2 is extruded and fixed with the inner wall of the drill hole, the water is injected into the water injection channel through the first water injection pipeline

3, filling water into the drill rod 1, so that the water is filled into the drill rod 1, and then the detector 11 in the drill rod 1 is fully coupled with the rock mass 0, thereby achieving the purposes of improving the detection precision and the accuracy of the detection result;

after the drill rod 1 is filled with water, the subsequent testing steps can be started.

The geological survey method and the plugging device for the mountain area underground engineering mouth part of the invention are explained in further detail by a specific embodiment.

The test target is mountain area A, the mountain slope is 35-45 degrees, and the position of the opening of the project is preset at the mountain foot of mountain area 5A. I.e. the test is located at the foot of mountain a with a slope between 35 deg. and 45 deg..

1. Survey of geological conditions of engineering port

The mountain foot of the mountain A is drilled with a horizontal hole in the mountain along the horizontal direction, the depth of the horizontal hole is about 140m, the aperture is 76mm, the horizontal hole is slightly inclined downwards, the inclination angle is controlled between 2 degrees and 5 degrees, and the whole hole is cored.

Making detailed borehole records, and analyzing sample materials taken out of the borehole to obtain stratum lithology near an outlet: the opening section is a covering layer, and the inside is orderly subjected to strong weathering, medium weathering and breeze.

2. Set up the observation device

Selecting a drill rod, and sealing one end of the drill rod; and feeding the cable provided with the 12 detectors into the drill rod from the opening at the other end of the drill rod, and plugging the opening of the drill rod by using a plugging device. And placing the drill rod into the horizontal hole, and pushing the cable and the detector to a specified detection position by pushing the drill rod.

As shown in fig. 3, the present detection is provided with 13 shots, the shots are arranged on a mountain slope at the upper part of the drill hole, 12 detectors are arranged in the drill hole, and the connecting line of the 13 shots is approximately positioned right above the detector string. The distance between two adjacent shots is 2m, the elevation of the shot 1 is 1959m, and the elevation of the shot 13 is 1969m; the distance between two adjacent detectors is 1m, and the distance from the detector to the drilling hole is 28m-39m.

3. Line connection

One end of the cable extends out of the drill rod through the plugging device, and the cable is connected with a host of the seismic wave prospecting instrument; connecting a first water injection pipeline with a cable on the plugging device; and connecting the second water injection pipeline with a connecting port on the plugging device.

Opening a second water injection pipeline to inject water into an expansion chamber of the plugging device, so that the expandable outer wall is expanded and fully contacted with the inner wall of the drilled hole;

after the expandable outer wall is extruded and fixed with the inner wall of the drill hole, the first water injection pipeline is opened to inject water into the water injection channel, so that the water is filled in the drill rod.

4. Performing seismic wave exploration

And starting the seismic wave exploration instrument, firing by adopting a large hammer focus at the positions from shot point 1 to shot point 13 in sequence, and enabling 12 detectors in the drill rod to acquire and record seismic wave data of each channel.

As shown in the wiring schematic diagram of the current detection in fig. 3, a plurality of seismic wave rays can be formed between the shot point and the detector, and the seismic wave rays are mutually intersected; in the range covered by the rays, the more and more dense the crossing conditions are, the higher the detection precision is, and the more accurate the detection result is.

5. Longitudinal wave inversion profile

Inversion calculation is carried out on each group of 12 channels and 13 groups of seismic wave records by using seismic tomography inversion software, and the longitudinal wave velocity distribution of the stratum between the shot point and the detector is obtained. As shown in FIG. 4, the wave velocity of the shallow part of the surface of the test part of the mountain A is 600m/s-800m/s, and is concave downwards, and the wave velocity gradually increases to about 2200m/s as the position gradually approaches the drilling hole.

6. Verification of test results

According to the wave velocity curve of the rock mass of the in-hole logging test, a longitudinal wave velocity curve chart of the in-hole logging 28m-39m shown in fig. 5 is obtained, and the average wave velocity is about 2220m/s. The longitudinal wave velocity of the drilling hole obtained by the detection is basically consistent with the data obtained by the in-hole logging, and the reliable result of the detection is fully described.

7. Wave velocity profile geological interpretation to form engineering geological map

According to the corresponding relation between lithology and wave velocity revealed by drilling, geological interpretation is carried out on the wave velocity distribution in FIG. 4 to obtain what is shown in FIG. 6, and it can be seen that the wave velocity of the shallow part is less than 800m/s, the wave velocity of the middle part is 800m/s-1500m/s, the strong weathering layer is arranged on the middle part, and the medium weathering layer is arranged on the lower part.

Further, as shown in fig. 1 and 2, the plugging device for geological survey of the mouth of an underground engineering in a mountain area according to the present invention, which is related to the above steps, has one end connected with the drill rod 1 in a sealing manner and the other end extending toward the mouth position of the engineering. The plugging device comprises an outer wall 2, wherein the outer wall 2 is annular, the annular outer wall 2 encloses into a cylindrical plug structure, and a containing space is formed in the outer wall 2. A water injection channel 3 is arranged in the accommodating space, a first end of the water injection channel 3 is communicated with the internal cavity of the drill rod 1, and a second end extends towards the opening position of the project; the water flow is injected from the second end of the water injection channel 3 and flows into the drill rod 1 through the first end of the water injection channel 3, so that the drill rod 1 is filled with water, the coupling effect of the detector in the drill rod 1 is improved, and the accuracy and precision of the detection result are improved.

Preferably, the second end of the water injection channel 3 is provided with a water injection joint 31, and the water injection joint 31 protrudes from the accommodating space surrounded by the outer wall 2, so as to be stably connected with a water pipe or other water injection devices, thereby improving water injection efficiency.

Further, a cable channel 4 is arranged in the receiving space, the cable channel 4 preferably being arranged parallel to the water injection channel 3. The first end of the cable channel 4 is communicated with the internal cavity of the drill rod 1, and the second end extends towards the mouth part of the project; a cable 12 with a plurality of detectors 11 is located in the drill rod 1, the end of which extends into the cable channel 4 from a first end and out of the plugging device through a second end of the cable channel 4 for connection to a host of the seismic survey. Sealing structures 41 such as sealing gaskets and sealing glue are arranged at the first end and the second end of the cable channel 4, the sealing structures 41 are arranged between the inner wall of the cable channel 4 and the outer wall of the cable 12, and water filled in the drill rod 1 can be prevented from flowing out of the drill rod 1 through the cable channel 4.

Further, an expansion chamber 5 is arranged in the accommodating space, and the expansion chamber 5 is in a ring shape as a whole and is arranged against the outer wall 2 of the plugging device; the outer wall 2 of the plugging device is an expandable outer wall 2, is made of elastic materials such as rubber and silica gel, has good elastic shrinkage capacity, and when a sufficient amount of fluid such as water or gas is filled in the expansion chamber 5, the pressure in the expansion chamber 5 is increased, so that the outer wall 2 expands outwards along the radial direction of the plugging device, the outer wall 2 is fully contacted with the inner wall of a drilled hole, and the effect of positioning and fixing is achieved. After the test is finished, the pressure in the expansion chamber 5 is removed, so that the outer wall 2 is separated from the inner wall of the drill hole, and the plugging device and the drill rod 1 are taken out of the drill hole.

The expansion chamber 5 is provided with a connection port 51, and the connection port 51 is preferably arranged on one side of the plugging device close to the engineering mouth part, so as to be connected with a water filling or inflating device, and fluid such as water or gas is filled into the expansion chamber 5. Preferably, the fluid filled into the expansion chamber 5 is water to enhance the coupling effect of the cable 12 and the pickup 11.

Preferably, an elongated connection channel is provided between the connection port 51 and the expansion chamber 5, and the connection port 51 communicates with the expansion chamber 5 through the connection channel. The elongate connecting channel increases the resistance to fluid flow and helps to maintain the pressure within the expansion chamber 5, providing a stable connection between the expansion chamber 5 and the expandable outer wall 2 and the inner wall of the borehole.

Preferably, the cable passage 4 and the water filling passage 3 are arranged in the middle of the plugging device accommodation space, and the expansion chamber 5 and the expandable outer wall 2 are arranged around the outside of the cable passage 4 and the water filling passage 3.

Preferably, the end that plugging device is connected with drilling rod 1 is provided with extension 6, and extension 6 stretches into the inside of drilling rod 1, and the inner wall laminating setting with drilling rod 1 to improve sealing connection effect between plugging device and the drilling rod 1.

The method for using the plugging device and the working flow are specifically described below with reference to the specific steps of the geological survey method for the mountain area underground engineering mouth.

As shown in fig. 2, in the step 3 of the geological survey method of the underground engineering mouth of the mountain area, the drill pipe 1 with the plugging device mounted thereon has pushed the cable 12 and the geophone 11 to the testing position, and the cable 12 extends out of the plugging device from the inside of the drill pipe 1 through the cable channel 4, and the cable 12 is connected with the cable channel 4 in a sealing manner through the sealing structure 41;

connecting the cable 12 with a host of the seismic prospecting instrument, connecting the first water injection pipeline with the water injection joint 31 of the water injection channel 3, and connecting the second water injection pipeline with the connection port 51 of the expansion chamber 5;

injecting water into the expansion chamber 5 through a second water injection pipeline to expand the expandable outer wall 2 and fully contact with the inner wall of the drilled hole; the second water injection pipeline is provided with a pressure test pump, and the water injection action of the second water injection pipeline can be stopped when the pressure of the pressure test pump reaches 0.4-0.6 MPa in general;

after the expandable outer wall 2 is extruded and fixed with the inner wall of the drill hole, water is injected into the water injection channel 3 through the first water injection pipeline, so that the water is filled in the drill rod 1, and further the detector 11 in the drill rod 1 is fully coupled with the rock mass, so that the purposes of improving the detection precision and the accuracy of the detection result are achieved;

after the drill rod 1 is filled with water, the subsequent testing steps can be started.

The geological survey method and the plugging device for the mountain area underground engineering mouth have the following advantages:

1. is not limited by the terrain, and is also applicable to the terrain environment with the mountain gradient of more than 30 degrees;

2. the surveying process is less influenced by external environment, the noise level is low, the surveying result is more reliable, and accurate geological information can be provided for the mouth structure and the protection design;

3. the cable and the sensor are not required to be paved on the surface of the mountain, so that the working efficiency is high, and the operation is convenient;

4. the inherent drilling structure in the survey process is fully utilized, the utilization rate of drilling is improved, and the survey cost is saved;

5. the plugging device enables the geological survey method not to be limited by the terrain, is applicable to the terrain environment with the mountain gradient larger than 30 degrees, and has the advantages of simple structure, convenient arrangement, more accurate survey results and higher precision.

The invention has been further described with reference to specific embodiments, but it should be understood that the detailed description is not to be construed as limiting the spirit and scope of the invention, but rather as providing those skilled in the art with the benefit of this disclosure with the benefit of their various modifications to the described embodiments.

Claims (10)

1. The geological survey method for the mountain area underground engineering mouth is characterized by comprising the following steps of:

determining the position of a mouth of an underground project, and carrying out geological investigation of the position of the mouth and the nearby area;

drilling a horizontal hole into the mountain along the horizontal direction at the position of the engineering opening, and recording the drilling;

selecting a drill rod according to the size of the horizontal hole, sealing the front end of the drill rod extending into the horizontal hole, and feeding a cable provided with a plurality of detectors into the drill rod;

placing the drill rod provided with the cable and the detector into the horizontal hole until the cable and the detector are pushed to the position to be detected;

injecting water into the drill rod from the rear end of the drill rod close to the engineering opening, filling water into the drill rod, and then plugging the rear end of the drill rod;

connecting a cable with a seismic wave prospecting instrument, starting the seismic wave prospecting instrument, arranging shot points on the ground surface above the horizontal hole, and firing by adopting a large hammer source at the position of the shot points to enable a wave detector in a drill rod to acquire seismic wave data of each channel;

and forming an engineering geological map according to the collected seismic wave data.

2. A mountain area underground works mouth geological survey method as claimed in claim 1, wherein when drilling the horizontal hole, the drilling direction is inclined downward in the horizontal direction by an angle of 2 to 5 degrees.

3. The mountain area underground engineering mouth geological survey method according to claim 1 or 2, wherein the rear end of the drill rod is plugged by a plugging device, the plugging device is provided with a water injection hole, the water injection hole is communicated with the inner space of the drill rod, and water is injected into the drill rod through the water injection hole.

4. A method of geological survey of a mountain subsurface engineering mouth as claimed in claim 3, wherein a cable passageway is provided in the plugging device, and a cable provided in the drill pipe is threaded out of the plugging device via the cable passageway to connect with the seismic prospecting instrument.

5. A method of geological survey of a mountain range subterranean engineering mouth as claimed in claim 4, wherein the cable is sealingly connected to the cable passage to prevent water within the drill pipe from flowing out of the drill pipe through the cable passage.

6. A method of geological survey of a mountain area underground works mouth as claimed in claim 3, wherein the plugging device comprises an expandable outer wall, an expansion chamber is arranged in the plugging device, fluid is injected into the expansion chamber before water is injected into the drill pipe, the pressure in the expansion chamber is increased, the outer wall is expanded outwards along the radial direction of the plugging device, and the outer wall is fixed in contact with the inner wall of the drill hole.

7. A method of geological survey of the mouth of a mountain subsurface project as claimed in claim 6, wherein the fluid charged into the expansion chamber is water to enhance the coupling effect of the detectors.

8. The mountain area underground engineering mouth geological survey method of claim 1, wherein two or more shot points can be arranged at two or more positions, and the firing of a large hammer source is adopted at the two or more shot point positions respectively, so that the seismic wave data acquisition of each channel is repeatedly carried out; before an engineering geological map is formed, inversion calculation is carried out on collected seismic wave data by utilizing seismic tomography inversion software, a longitudinal wave velocity distribution map of a stratum between a shot point and a detector is obtained, and a test result is verified compared with a rock mass wave velocity curve result of an in-hole logging test.

9. The plugging device is applied to the geological survey method of the mountain area underground engineering mouth part, and is characterized by comprising a device body, wherein one end of the device body is in sealing connection with a drill rod, the other end of the device body extends towards a direction away from the drill rod, a water injection channel and a cable channel are arranged in the device body, the water injection channel and the cable channel are communicated with an inner cavity of the drill rod, water flows into the inner cavity of the drill rod through the water injection channel, and a cable in the drill rod extends out of the drill rod through the cable channel; the surface of the device body is provided with an annular outer wall, an expansion chamber is arranged in the device body and is arranged close to the outer wall, the outer wall is an expandable outer wall with elastic contraction capacity, and the expandable outer wall can expand or contract along with the increase and decrease of the pressure in the expansion chamber; the cable channel and the water injection channel are arranged in the middle of the device body, and the expansion chamber and the expandable outer wall are arranged outside the cable channel and the water injection channel in a surrounding mode.

10. The plugging device of claim 9, wherein the first end of the cable passageway is disposed in communication with the interior cavity of the drill pipe and the second end extends away from the drill pipe, the cable in the drill pipe extending from the first end of the cable passageway and out of the second end of the cable passageway, the first and second ends of the cable passageway being provided with a seal structure disposed between the inner wall of the cable passageway and the outer wall of the cable.

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