JP4697634B2 - Underground pollution investigation method - Google Patents

Description

  The present invention relates to an underground contamination investigation method for investigating the existence position of contaminants in the ground using a horizontal drilling system that forms a so-called horizontal well in the ground.

  In recent years, the diffusion of pollutants into the ground has been regarded as a problem, and pollution investigations are being carried out in pollutable areas where the probability of contamination is high. Specifically, this contamination investigation includes a method of drilling in a direction perpendicular to the ground (in the depth direction of the ground) using a hollow bore tube and analyzing the sample in the hollow bore tube collected by this borehole. Also, there is a method of analyzing the sucked sample by providing a suction hole at the tip of the hollow drilled tube and sucking air and fluid existing in the ground (for example, Patent Document 1).

Further, as another method for contamination surveys, for a vertical well formed in the direction perpendicular to the ground, forming a plurality of horizontal wells in a radial direction from the different depth of several positions of the vertical wells around its longitudinal well survey There is a method of collecting a sample (for example, Patent Document 2).
JP 2003-279552 A JP 2004-353166 A

  However, the above-described method for boring in the direction perpendicular to the ground is a survey in which a hole is made at one point on the ground when viewed from the area of the contaminatable area. Therefore, in combination with the tendency of pollutants to diffuse in the ground, when the pollutable area occupies a large area, it becomes necessary to carry out numerous boring operations, which makes the operation extremely complicated. . In addition, in an area covered with a building or the like, a boring machine cannot be installed and a boring survey is often impossible.

Moreover, when forming the above-mentioned vertical well and horizontal well, the construction for forming these wells is troublesome and takes time, and is a so-called large construction as compared with the above-described boring.

The present invention has been invented in view of the above, and does not require a large number of boring surveys as in the prior art, and only a small number of surveys are possible, and it is also possible to investigate an area covered with a building or the like. Another object of the present invention is to provide a method for investigating underground contamination that allows simple drilling work without digging vertical wells or horizontal wells as in the prior art.

In order to solve the above-described problems and achieve the object, the feature of the invention described in claim 1 is that a sheath tube, a drilling rod inserted through the sheath tube, and a tip of the drilling rod are connected. And a drilling device provided with a drilling bit whose rotation direction can be controlled by rotation about the axial direction of the drilling rod, and the drilling rod centered in the axial direction. The position of the drill bit is measured based on data from a support device that pushes and extrudes the sheath tube along its axial direction while rotating it, and position detection means provided at the tip of the drill rod. A horizontal drilling system equipped with a position measuring device is used to set the position of the horizontal drilling in advance in the underground contamination survey planned area, and to set the planned measurement point in the set horizontal drilling, according to the setting of the position of the drilling, the support device And at the same time promote the sheath pipe more while extruding the drilling rods, the horizontal by ejecting the mud from the drilling bit mud through the drilling for the rod from the support apparatus is supplied to the drilling bit After confirming that only the muddy water returns to the ground through the sheath tube by drilling and stopping the extrusion of the drilling rod by the support device at the position before each scheduled measurement point and supplying the muddy water, By resuming the extrusion of the rod for drilling by the support device, the soil mixed mud mixed with the soil at the predetermined measurement point and the mud is transferred to the ground from the drain hole provided in the sheath pipe through the sheath pipe. The purpose is to measure the presence / absence and the degree of inclusion of contaminants in the soil mixed with mud.

The feature of the invention of claim 2 is that, in addition to the structure of claim 1, the required number of the horizontal drilling holes are arranged in the ground contamination survey planned area in three dimensions with intervals in the vertical and horizontal directions. Measure the distribution of pollutants in the planned underground contamination survey area by measuring the presence or absence of contamination in the soil from each planned measurement point of each horizontal drilling hole at the set position . There is to do.

  According to the present invention, by rotating around the axial direction of the drilling rod, which is connected and fixed to the sheath tube, the drilling rod inserted through the sheath tube, and the tip of the drilling rod. A drilling device provided with a drilling bit whose control direction is controllable, and an operation of pushing the rod for drilling and propelling the sheath tube along the axial direction while rotating the drilling rod about the axial direction. Using a horizontal drilling system comprising a support device and a position measuring device that measures the position of the drilling bit based on data from position detection means provided at the tip of the drilling rod,

Along with the operation of the support device, the sheath tube is pushed while pushing the drilling rod, and at the same time, muddy water is supplied from the support device through the drilling rod to the drilling bit, and the muddy water is supplied to the drill bit. A horizontal drilling hole is formed by spraying, and the mixed soil mud mixed with the ground and mud from the drilled hole is returned to the ground through the drainage hole provided in the sheath pipe, and the mixed soil mud By using the drilling device and the support device to make so-called horizontal drilling directly from the ground by measuring the presence or absence and the degree of inclusion of the contaminant in the ground, As the drill rod progresses, the soil is collected by muddy water injection, and the soil and muddy water are sucked and supplied to the pollutant detection device, so the formation of a horizontal well consisting of one horizontal drill hole. Many It is possible to investigate the area, and only a few surveys are required compared to many surveys such as boring surveys, and the drilling device travels horizontally in the ground, so it was covered with buildings etc. It is possible to investigate the area, and since it is sufficient to make a horizontal drilling without digging a vertical well or horizontal well as in the conventional case, it is a simple drilling operation.

Further, according to the present invention, the required number of horizontal drilling positions are set in a three-dimensional arrangement with an interval in the vertical and horizontal directions in the planned underground contamination survey area, and each horizontal drilling is set at regular intervals. By setting the planned measurement points and measuring the presence or absence of contaminants in the soil from each planned measurement point, the distribution of pollutants in the ground can be easily measured. Can be investigated.

Furthermore, according to the present invention, it was confirmed that only the muddy water returns to the ground through the sheath tube by stopping the extrusion of the drilling rod by the support device at the position before the scheduled measurement point and supplying the muddy water. Thereafter, by repeating the operation of resuming the extrusion of the drilling rod by the support device and determining the planned measurement point, that is, the sampled sampling position, if the measurement point is determined, the soil at that position is determined. Can be clearly distinguished from other soil cuttings, and the soil contamination status at the measurement point can be grasped with high accuracy.

  BEST MODE FOR CARRYING OUT THE INVENTION The best embodiment of the underground pollution investigation method according to the present invention will be described in detail below. Here, the horizontal drilling system used in the present invention will be described.

  As shown in FIG. 1, this system includes a drilling device B that forms a horizontal well, and a support device S that pushes the drilling device B into the ground. The drilling device B is connected to the bendable sheath tube 1, the bendable drilling rod 2 inserted through the center of the sheath tube 1, and the tip of the drilling rod 2. A flexible tip rod 2a protruding outside the tip portion and a drill bit 3 fixed to the tip portion of the flexible tip rod 2a are provided.

  The support device S is located on the ground and digs by performing an extruding operation while rotating the drilling rod 2 and the flexible tip rod 2a, and performs the operation of propelling the sheath tube 1 by following this operation. It is.

  Further, in this drilling device B, an azimuth / inclination angle detection device D as a position detecting means is installed at the tip of the drilling rod 2 so as to be able to rotate integrally with the drilling rod 2, and this azimuth tilt The position of the excavation bit 3 is measured by the computer C provided on the ground based on the detection data from the angle detection device D.

  The azimuth / inclination angle detector D operates in conjunction with the tip of the drilling rod 2 and detects the same azimuth and tilt angle as the tip of the drilling rod 2. And the positional information measured by the position measuring device which consists of this azimuth | direction inclination angle detection apparatus D computer C is sent out as information for making the next operation | work of the assistance apparatus S advance.

  Further, the rotation of the drilling rod 2 and the amount of extrusion and the reference point P of the support device S associated with the work of the support device S and the reference point P of the support device S are input to the computer C, respectively. The calculation result is displayed on the display device d of the computer C and is reflected as the traveling path of the drilling rod 2.

  2 and 3 are diagrams for explaining the underground pollution investigation method. The underground pollution investigation apparatus will be further described with reference to these drawings. FIG. 2 shows a tip portion of the hole drilling device B. The drilling rod 2 and the flexible tip rod 2a are hollow so that muddy water is supplied from the support device S. As shown in the enlarged view of FIG. 2, the drill bit 3 fixed to the tip of the flexible tip rod 2a has a pressure receiving surface 3a inclined with respect to the axial direction. Similarly, the muddy water injection nozzle 3b is inclined.

  For this reason, when the drilling rod 2 is pushed out by the support device S, earth pressure is applied to the inclined pressure receiving surface 3a of the drill bit 3 and the earth pressure acts (downward in the enlarged view of FIG. 2). In addition, the drill bit 3 and thus the drill rod 2 are bent. At this time, the muddy water from the injection nozzle 3b is inclined and injected.

  When the drilling rod 2 is rotated by the support device S, the earth pressure is uniformly applied to the pressure receiving surface 3a of the drilling bit 3 by the extrusion of the drilling rod 2 by the support device S. Therefore, the drill bit 3 and the drill rod 2 go straight. At this time, the muddy water sprayed with an inclination from the spray nozzle 3b acts uniformly with the rotation and cuts the soil in the straight direction.

  As shown in the enlarged view of FIG. 2, the azimuth angle detector D connected to the tip of the drilling rod 2 includes a cylindrical measuring case 4 that forms the outer shell of the device, and a measuring case 4 inside. The sensor support 5 disposed on the sensor support 5, and the sensor support 5 via the rotary table 6, and the center axis y of the measurement case 4 and the axis x orthogonal to the center axis and parallel to the sensor support 5 are arranged. A tuned dry gyro 7 serving as an input shaft and an accelerometer 10 that is supported by the sensor support 5 via the rotary tables 8 and 9 and detects acceleration in the direction of the central axis y of the measurement case 4 and orthogonal to the central axis. An accelerometer 11 that detects acceleration in the direction of the axis x in parallel with the sensor support 5, a rotation control means 12 that rotates the turntables 6, 8, and 9 synchronously, and a rotation angle of the turntable 9 are detected. Rotation angle detection means 13 and tuned dry gyroscope 7, Based on the output from the speedometer 10, 11 and the rotation angle detecting means 13 and a calculating means 14 for calculating the inclination and azimuth of the sensor supporting plate 5 thus drilling rod 2. Reference numeral 15 in the figure denotes an accelerometer that measures acceleration in the z-axis direction.

  The azimuth / inclination angle detector D feeds back the output from the accelerometer 11 as necessary, and adjusts the position of the sensor support 5 so that the sensor support 5 is in a horizontal state around the central axis. Be able to.

  Also, at the tip of the sheath tube 1 shown in FIG. 2, the muddy water sprayed from the spray nozzle 3 b of the drill bit 3 and the soil cut by the muddy water are directed toward the support device S through the sheath tube 1. A drain hole 1a for returning is formed.

  In the support device S, the base end portion of the sheath tube 1 is provided with a swivel joint 1b as shown in FIG. 3, and the drain pipe 21 is connected to the suction pump 20 through the drain port 1c of the swivel joint 1b. It has become. In FIG. 3, reference numeral 22 denotes a pollutant detection device provided in the middle of the drain pipe 21.

  Next, the underground pollution investigation method of this embodiment will be described.

First, as shown in FIG. 7, the positions of the required number of horizontal holes 40, 40... Similarly, the positions of the horizontal holes 40 , 40 arranged in several stages are set in the vertical direction. This setting should be avoided under piles and other obstacles such as piles. And the scheduled measurement point M is set for every horizontal drilling 40 for every fixed interval. In the figure, reference numeral 43 denotes a building existing in the underground contamination survey scheduled area W.

Next, drilling is performed according to this setting, and the content rate of the pollutant is measured for the soil at the planned measurement point M for each horizontal drilling hole 40. Depending on the presence or absence of the contaminant at each planned measurement point M and the detected concentration, As shown in FIGS. 6 and 7, the three-dimensional contamination range 41, and the contaminant distribution such as the high-concentration contamination region 42 therein are discriminated. Incidentally, FIG. 6, × mark in FIG. 7 shows a predetermined measuring point M, single circles scheduled measuring point M contaminants are detected, denoted by the double circle in the measurement point detected in a high concentration Yes.

  In each horizontal drilling hole 40, when the drilling rod 2 is pushed into the ground by the support device S shown in FIG. 1, the drilling bit 3 and the drilling rod 2 are formed on the pressure receiving surface 3 a of the drilling bit 3. Turn up, down, left, right in the ground depending on the direction. Further, by pushing and rotating the drilling rod 2 into the ground, the drilling bit 3 and the drilling rod 2 go straight through the ground. And the sheath tube 1 is propelled with the extrusion of the drilling rod 3. As a result, the hole drilling device B travels in the ground.

  Muddy water is supplied from the support device S through the drilling rod 2 as the drilling device B advances into the ground. And this muddy water is injected from the injection nozzle 3b of the drill bit 3. This muddy water cuts the soil in the ground, and the soil is mixed with muddy water. Then, along with suction by the suction pump 20, the soil and muddy water return outside the flexible tip rod 2 a and are sucked into the drain hole 1 a at the tip of the sheath tube 1. The soil and muddy water sucked into the drain hole 1a are sent to the support device S through the inside of the sheath tube 1 and sent from the drain port 1b to the pollutant detection device 22 through the drain tube 21. If there is a pollutant in the soil, this pollutant detection device 22 detects its concentration.

  Here, the pollutants to be detected include, for example, volatile organic compounds and oils. Specifically, dichloromethane, carbon tetrachloride, 1,2-dichloroethane, 1,1-dichloroethylene, cis-1,2-dichloroethylene, 1,1,1-trichloroethane, 1,1,2-trichloroethane, trichloroethylene, tetrachloroethylene, and the like can be given. Examples of the contaminant detection device include a PID sensor, a process gas chromatograph, and a sparging tank.

  In addition, the muddy water used in the present embodiment dissolves, for example, bentonite which has a property that the groundwater is difficult to permeate and has a large specific surface area in order to prevent the intrusion of the groundwater and the collapse of the formed hole. It is a thing.

  In the present embodiment, in order to further effectively use the muddy water, a method of circulating the muddy water as shown in FIG. 4 is adopted. The mud containing the soil is sucked by the suction pump 20 and then sent to the vibration unit 23 with a cyclone to separate the earth and sand from the mud. The separated earth and sand are sent to the contaminant treatment system 27 and subjected to the contamination treatment. Since the remaining muddy water contains contaminants, the contaminants are precipitated in the sedimentation tank 24.

  The muddy water after the precipitation is sent to the pollutant concentration adjusting tank 25 and to the pollutant removing device 28. In this contaminant removal apparatus, contaminants are removed from the muddy water and stored in the muddy water tank 26. In the pollutant concentration adjusting tank 25, a part of the muddy water in the muddy water tank 26 is returned to adjust the concentration. Then, the muddy water stored in the muddy water tank 26 is sent to the support device S and supplied into the drilling rod 2. Thus, by circulating the muddy water, the muddy water can be eliminated and the muddy water can be effectively used.

  FIG. 5 illustrates an apparatus for sampling the muddy water while circulating the muddy water containing the soil. Here, a valve 31 is provided in the middle of a pipe 30 through which mud containing soil is passed, and pipes provided with valves 32 and 33 are branched upstream and downstream of the valve 31, respectively. The two branch pipes communicate with the tank 34. The tank 34 is provided with a sample outlet 35, and muddy water is sampled into the sample container 36 through the sample outlet 35. Reference numeral 37 denotes a fluoroscopic level meter for observing the amount of muddy water in the tank 34 from the outside.

  In this apparatus, the muddy water passes through the pipe 30 by opening the valve 31 and closing the valves 32 and 33. When the valve 31 is closed and the valves 32 and 33 are opened, the muddy water is guided and stored in the tank 34. When the muddy water overflows into the tank 34, the muddy water returns to the pipe 30 through the valve 33. In this way, the muddy water sample can be easily taken out of the tank 34.

  The computer C connected to the support device S shown in FIG. 1 is preliminarily inputted with the drilling route information of the pollutable investigation area, and has a plan view as shown in FIG. 6 and a longitudinal sectional view as shown in FIG. It is displayed on the display device d. In this display, the position of the building or the state of obstacles in the ground such as foundation piles and pipes is shown in advance. Then, the traveling path of the drilling device B is input and displayed so as to avoid the position of the obstacle.

  Further, the slip position of the reference point P is input to the computer C and displayed on the display device d. When forming the horizontal well, the reference point P of the support device S shown in FIG. 1 and the reference point P seat position of the display device d are aligned, and the extrusion of the drilling rod 2 is started. The pushing amount of the drilling rod 2 is obtained from the support device S, and the azimuth and the tilt angle of the drilling rod 2 are obtained from the azimuth tilt angle detection device D. Accordingly, the current position of the tip of the drilling rod 2 is determined from the extrusion amount, the azimuth, and the inclination angle of the drilling rod 2 by calculation processing by a computer, and the drilling rod is formed on the traveling path displayed on the display device d. The current position of the tip of the rod 2 can be plotted.

Further, the computer C receives and displays a planned measurement point M on the traveling path as displayed on the display device d. This scheduled measurement point M is a seat position for reliably collecting the cut soil at that position. The drilling rod 2 is pushed out by the support device S, and the drilling rod 2 is pushed out by the support device S in a state where the computer has monitored that the tip position of the drilling rod 2 has reached the predetermined measurement point M. Stop. In this state, only the muddy water is circulated without the drilling device B moving. That is, muddy water is supplied into the drilling rod 2 and muddy water is discharged from the injection nozzle 3b of the drilling bit 3, but the muddy water is returned to the support device S from the drainage hole 1a of the sheath tube 1 without being cut. . If the extrusion of the drilling rod 2 by the support device S is resumed in this state, the first detected soil is the planned measurement point M. A reliable cutting of the planned measurement point M is obtained.

It is a side view which shows the schematic whole structure of the hole drilling apparatus used for this invention method. It is a block diagram of the front-end | tip part of the same hole drilling apparatus. It is sectional drawing which shows the front-end | tip part of the same hole drilling apparatus. It is a simplified system diagram which shows the muddy water circulation system used for this invention method. It is a simplified block diagram of the same muddy water sampling apparatus. It is a top view which shows arrangement | positioning of a plan horizontal drilling hole and a measurement point. It is the longitudinal cross-sectional view.

B Drilling device S Support device C Computer D Direction / tilt angle detection device P Reference point d Display device M Measurement point W Underground contamination investigation planned area 1 Sheath pipe 1a Drainage hole 1b Drainage port 2 Drilling rod 3 Drilling bit 3a Pressure receiving surface 3b Injection nozzle 7 Tuned dry gyro 10, 11, 15 Accelerometer 20 Suction pump 22 Contaminant detection device 24 Precipitation tank 25 Contaminant concentration adjustment tank 26 Mud water tank 27 Contaminant treatment system 28 Contaminant removal apparatus 30 Pipe 31, 32, 33 Valve 34 Tank 35 Sample outlet 36 Sample container 37 Perspective level meter 40 Horizontal drilling hole 41 Contamination range 42 High concentration contamination area

Claims (2)

Advancing direction can be controlled by rotation around the axial direction of the above-mentioned drilling rod, which is connected and fixed to the sheathing tube, the drilling rod inserted through this sheathing tube, and the tip of this drilling rod A drilling device provided with a drilling bit, a support device for performing the work of pushing the sheathing rod along the axial direction while pushing the rod for drilling while rotating the drilling rod around the axial direction; Using a horizontal drilling system provided with a position measuring device that measures the position of the drilling bit based on data from a position detection means provided at the tip of the hole rod,
Set the horizontal drilling position in advance in the planned underground contamination survey area, set the planned measurement point for the set horizontal drilling hole ,
According to the setting of the horizontal drilling position, this at the same time when promoting sheath pipe while extruding the drilling rod by the support apparatus, the mud through the drilling for the rod from the support apparatus is supplied to the drilling bit By drilling muddy water from the drilling bit, drilling horizontally,
After confirming that only the muddy water returns to the ground through the sheath pipe by stopping the extrusion of the drilling rod by the support device at the position before each scheduled measurement point and supplying the muddy water, the cutting by the support device is performed. By resuming the extrusion of the hole rod, the soil-mixed muddy water, in which the soil at the predetermined measurement point and the muddy water are mixed, is returned to the ground through the drainage hole provided in the sheath pipe, and the ground A method for investigating underground pollution characterized by measuring the presence or absence and the degree of inclusion of contaminants in soil mixed mud. Set the required number of horizontal drilling holes in a three-dimensional arrangement with vertical and horizontal intervals in the planned underground contamination survey area, and measure each horizontal drilling at the set position . The underground pollution investigation method according to claim 1, wherein the distribution of contaminants in the planned underground pollution investigation area is measured by measuring the presence or absence of contaminants in the cut soil from a point.