JP2012207471A - Excavation method of underground hole and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an excavation method of an underground hole, preventing excavation of the underground hole from being interfered by outflow of artesian water from a water-containing layer and blowout of sediment accompanying this even when confronting the water-containing layer containing the artesian water in excavating the underground hole by using an excavation fluid.SOLUTION: When confronting a water-containing layer in excavating an underground hole by using a drill pipe, the excavation is carried out while balancing the pressure of artesian water with a back pressure by raising the injection pressure of an excavation fluid injected from nozzles of drilling bits passing through the inside of a drill pipe and provided on the front end of a drill pipe and discharged through an outer peripheral passage of the drill pipe, and by applying the back pressure countering the pressure of the artesian water from the water-containing layer to an excavation fluid discharge part.

Description

  The present invention relates to an underground hole excavation method and apparatus.

  As a technique for laying underground pipes such as a water conduit in the ground, there is an arc-shaped propulsion technique capable of excavating a pipe along an arbitrary planned curve from the surface to the ground (for example, Patent Documents 1 and 2). reference.).

  According to this technology, a drilling tool is attached to the tip of the drill pipe, and the locus of the hole is adjusted according to the desired orientation, inclination, and position of the hole along the planned curve entering the ground from the ground surface. An underground hole can be formed, for example, an underground hole passing through a rock layer under a river, under the seabed, or in a mountainous area.

  Drilling fluid is used for excavation of underground holes. The drilling fluid usually passes through the inside of the drill pipe of the drilling tool, is jetted from the nozzle of the drill bit at the tip, passes between the inside of the underground hole and the outside of the drill pipe, returns to the starting point, and is recycled. Such a drilling fluid plays a role of transporting swarf and earth and sand generated by excavation to the starting point. As the drilling fluid, for example, fresh water or viscous mud water is used. More specifically, for example, clear water is used when excavating uphill underground holes in mountainous areas, and viscous mudwater is used when excavating horizontal or downwardly inclined underground holes in mountainous areas. It is done.

  When constructing such an underground hole, for example, if it adheres to a hydrous layer with pressurized water, the drilling fluid will be diluted by the outflow of pressurized water from the hydrous layer. In excavation of underground holes that use viscous mud as the drilling fluid, if the drilling fluid is diluted, it may hinder the transport of debris and earth and sand generated by the drilling, and the drilling fluid may become unusable. is there. In addition, the crushed layer in which the rock mass is crushed has many gaps between the crushed rock fragments, and the gap contains water and is a hydrous layer with pressurized water There is a case. And if it adheres to such a crushing layer, a lot of earth and sand may spout in a underground hole with the outflow of pressurized water. When such earth and sand eruption occurs, the space between the underground hole and the outside of the drill pipe is clogged with earth and sand, and there is a possibility that the circulation and use of the drilling fluid may be hindered and the advance and retreat of the drill pipe may be hindered.

  As a conventional technique for avoiding such a problem, there is known a technique for stopping pressurized water flowing out of the hydrous layer from flowing into the underground hole by injecting a chemical solution into the hydrous layer that has been grasped in advance. Yes. However, the technique for preventing the pressure water from flowing out from the water-containing layer by injecting the chemical solution has problems that the construction is highly difficult and the cost is high depending on the area where the water-containing layer exists.

  In many cases, the existence area of the hydrous layer cannot be ascertained in advance, and in such a case, if the outflow of pressurized water occurs on the hydrous layer with the pressurized water during excavation of the underground hole, Even if the chemical solution is injected from the inside hole, for example, the injected chemical solution is not completely injected due to the water pressure of the pressurized water, and it is difficult to perform the construction.

Further, the seal of the mouth of the conventional underground boring device has a drawback that it wears violently.
JP-A-10-317883 Japanese Patent No. 3542108

  In the present invention, when excavating an underground hole using a drilling fluid, even if it adheres to a hydrous layer with pressurized water, An object of the present invention is to provide a method for excavating an underground hole that prevents the excavation from being hindered.

  Moreover, this invention provides the apparatus which can implement suitably the excavation method of the said underground hole.

  While the above method provides a back pressure application technique using a drilling fluid, the apparatus also provides a technique for reliably and permanently achieving the sealing function that occurs at that time.

The method for excavating an underground hole of the present invention to achieve the above object is as follows.
When drilling the underground hole using a drill pipe, when it is attached to the hydrous layer, it is injected from the nozzle of the drill bit provided at the tip of the drill pipe through the inside of the drill pipe and passes through the outer peripheral passage of the drill pipe. While increasing the injection pressure of the drilling fluid to be discharged, a back pressure against the pressure of the pressurized water from the water-bearing layer is applied to the discharge portion of the drilling fluid to balance the pressure of the pressurized water and the back pressure. It is characterized by excavating.

  The excavation method for underground holes according to the present invention increases the injection pressure of the drilling fluid when attached to the hydrous layer, and also applies a back pressure against the pressure of the pressurized water from the hydrous layer to the discharge portion of the drilling fluid. Since the pressure of the pressurized water and the back pressure are balanced, it is avoided that the pressurized water from the hydrous layer flows out into the underground hole, and the drilling fluid is diluted with the pressurized water. It is possible to excavate underground holes while preventing this. Moreover, by avoiding the outflow of the pressurized water from the water-containing layer, it is also possible to prevent the earth and sand from being ejected into the underground hole with the outflow of the pressurized water. Therefore, according to the underground hole excavation method of the present invention, the underground hole can be excavated by the outflow of the pressurized water from the hydrous layer and the eruption of the earth and sand accompanying this, even if it adheres to the hydrous layer with the pressurized water. It is effectively prevented from being disturbed.

Moreover, the excavation apparatus for underground holes of the present invention that achieves the above object is provided with a closing portion that closes the entrance of the underground hole excavated with a drill pipe,
(A) a back pressure applying unit that applies a back pressure against the pressure of the pressurized water from the water-containing layer to the drilling fluid discharge unit; and (b) the drill pipe penetrates and the back pressure of the drilling fluid is on the outer diameter. And a seal having a mechanism for allowing the drill pipe to advance and retreat into the underground hole and to rotate integrally with the drill pipe.

  According to the underground hole excavation apparatus of the present invention, the pressure of the pressurized water from the water-containing layer in the excavating fluid discharge part is the back pressure application part provided in the closing part that closes the entrance of the underground hole to be excavated. By applying a back pressure against the pressure, the pressure of the pressurized water and the back pressure can be balanced. Thereby, it is avoided that the pressurized water coming out of the hydrous layer flows into the underground hole, and the underground hole can be excavated while preventing the drilling fluid from being diluted with the pressurized water. Moreover, by avoiding the outflow of the pressurized water from the water-containing layer, it is also possible to prevent the earth and sand from being ejected into the underground hole with the outflow of the pressurized water. Further, since the seal is a cylindrical body through which the drill pipe penetrates and receives the back pressure of the drilling fluid at the outer diameter, the inner diameter is pressed against the outer diameter of the drill pipe by receiving the water pressure at the outer diameter. Therefore, it is not necessary to apply a compressive force from the outer peripheral direction to the seal by external pressure such as hydraulic pressure in order to stop water. In addition, since the seal allows the drill pipe to advance and retreat into the underground hole and has a mechanism that rotates integrally with the drill pipe, the portion of the seal that is in contact with the drill pipe rotates the drill pipe. To avoid wear. Therefore, the water stop performance is maintained regardless of whether the drill pipe is moved forward or backward and rotated, and the water stop of the pressurized water can be achieved permanently and effectively. Therefore, according to the excavation device for underground holes of the present invention, excavation of underground holes is possible by outflow of pressurized water from the hydrous layer and eruption of earth and sand associated therewith, even if stuck to the hydrous layer with pressurized water. It is possible to effectively prevent obstruction.

  According to the underground hole excavation method and apparatus of the present invention, the underground hole is excavated by the outflow of the pressurized water from the hydrous layer and the accompanying earth and sand ejection even if it adheres to the hydrous layer with the pressurized water. There is provided a technique for effectively preventing obstruction.

It is a side view which shows one Embodiment about the excavation apparatus of the underground hole of this invention. It is an enlarged view of the A section shown in FIG. It is a longitudinal cross-sectional view which shows the digging opening water stop apparatus of the conventional underground boring apparatus.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a side view showing an embodiment of an underground hole excavation apparatus according to the present invention. FIG. 2 is an enlarged view of a portion A shown in FIG. In addition, about A section shown in FIG. 1, the longitudinal cross-section is shown.

  An underground hole excavating apparatus 100 according to the present embodiment shown in FIG. 1 is an excavating apparatus that excavates a horizontal hole along a planned curve in a mountainous area using a drill pipe 200.

  As shown in FIG. 1, the underground hole excavating apparatus 100 includes a conductor pipe 110 inserted into an inlet of an underground hole drilled by a drill pipe 200, and an inlet of the underground hole connected to the conductor pipe 110. The closing part 120 which closes is provided. This closing portion 120 is an embodiment of the closing portion referred to in the present invention. The closing portion 120 is provided with four ball valves 1221, 1222, 1223, 1224 provided via a manifold 121, and a water stop rubber 123.

  The drill pipe 200 plays a role of feeding a drilling fluid into the underground hole. The drill pipe 200 is composed of a tube part 210 and a tool joint part 220 having a diameter larger than that of the tube part 210, and the tool joint part 220 is threaded to add the drill pipe 200. is there. Although not shown, a drill pipe 200 is equipped with a non-magnetic collar having a measuring device for measuring geomagnetism, followed by a mud motor and a drill bit that is rotationally driven by the mud motor. And are attached. In excavation of the underground hole, it passes through the inside of the drill pipe 200, is sprayed from the nozzle of the drill bit at the tip, passes between the inside of the underground hole and the outside of the drill pipe 200, returns to the starting point, and is recycled. The drilling fluid delivered using a high-pressure pump (not shown) is injected into the starting point of the drill pipe 200. Thereby, the mud motor rotates, the rotation is transmitted to the excavation bit, and the underground hole is excavated. The mud motor is bent at a predetermined angle with respect to the drill pipe 200 at a substantially intermediate portion. Therefore, a bent underground hole is formed by excavating the drill pipe 200 without rotating it about the axis. Further, a straight underground hole is formed by excavating while the drill pipe 200 is rotated around the axis.

  The four ball valves 1221, 1222, 1223, and 1224 provided in the closing part 120 are valves having different diameters that discharge drilling fluid from the underground hole with the inlet closed to the outside of the underground hole. When the water-containing layer with pressurized water is not attached, all four ball valves 1221, 1222, 1223, and 1224 are fully opened. As described above, by using the ball valve at the discharge location of the drilling fluid, it is possible to prevent the discharge location from being clogged with digging waste and earth and sand mixed with the drilling fluid. In addition, 2 inches, 4 inches, 6 inches, and 8 inches are used here. These four ball valves 1221, 1222, 1223, and 1224 are also valves that apply a back pressure against the pressure of the pressurized water from the water-containing layer when attached to the water-containing layer with the pressurized water. More specifically, the pressure loss is generated by closing the ball valve corresponding to the pressure of the pressurized water from the water-containing layer among the four ball valves 1221, 1222, 1223, 1224, and as a result, the pressurized water A back pressure against this pressure is applied. As a result, the pressure of the pressurized water and the back pressure are balanced. By closing the ball valve having a large diameter among the four ball valves 1221, 1222, 1223, and 1224, a larger back pressure can be applied than when closing the ball valve having a small diameter. Then, by combining four ball valves 1221, 1222, 1223 and 1224 having different diameters, a desired back pressure is applied in the underground hole. The combination of the four ball valves 1221, 1222, 1223, and 1224 is an example of the drainage portion and the back pressure application portion according to the present invention. The back pressure against the pressure of the pressurized water from the water-containing layer may be a back pressure that is balanced with the pressure of the pressurized water, or a back pressure that is slightly larger than the pressure of the pressurized water. There may be. Further, the fine adjustment of the back pressure to be applied is performed by combining the adjustment of the pressure for sending the drilling fluid in the high-pressure pump with the opening and closing of the ball valve.

  Here, the seal of the mouth of the conventional underground boring apparatus will be described with reference to FIG.

  In FIG. 3, the longitudinal cross-sectional view of the excavation mouth water stop apparatus of the conventional underground boring apparatus was illustrated.

  For example, as shown in FIG. 3, a conventional underground boring device has an elastic seal 310 made of rubber or the like on the outer periphery of a portion to be water-stopped. The elastic seal 310 was of a type in which a compressive force was applied from the outer peripheral direction.

  Here, the drill pipe is used while being rotated around an axis as necessary during excavation. Further, as described above, the elastic seal 310 applies a compressive force applied to the elastic seal 310 to stop water by pressure from the outside. Therefore, such an elastic seal 310 is stationary, and when the drill pipe is rotated, there is a problem in that the portion of the elastic seal 310 that is in contact with the drill pipe is severely worn.

  Returning to FIG. 1 and FIG. 2, the description of the underground hole excavating apparatus 100 of this embodiment will be continued.

  The water stop rubber 123 provided in the closing portion 120 of the underground hole excavating apparatus 100 of the present embodiment is a seal through which the drill pipe 200 passes, and is a spindle-like self-tightening cylinder. The water stop rubber 123 has an outer diameter 1232 that receives the back pressure of the drilling fluid, and the drill pipe 200 is allowed to advance and retreat into the underground hole. Therefore, when the drill pipe 200 is moved forward and backward, the inner diameter 1231 of the water stop rubber 123 is not only the outer diameter 211 of the pipe body part 210 of the drill pipe 200 but also the outer diameter 221 of the tool joint part 220 of the drill pipe 200. Crimp. Therefore, it is not necessary to apply a compressive force from the outer peripheral direction to the water stop rubber 123 by an external pressure such as hydraulic pressure for water stop. Further, since the water stop rubber 123 does not need to apply a compressive force due to external pressure, it can be rotated integrally with the drill pipe 200. The water stop rubber 123 includes the drill pipe 200. And a rotation mechanism that rotates together with the rotation mechanism. More specifically, the water stop rubber 123 is detachably attached to a steel rotating body 124 that is rotatably provided via a bearing 125 with respect to the pipe body 126 using a bolt 1241. It rotates with the rotating body 124. By providing such a rotation mechanism in the water stop rubber 123, it is avoided that the portion of the water stop rubber 123 that is in contact with the drill pipe 200 is worn by rotating the drill pipe 200. Therefore, the water stop performance is maintained regardless of whether the drill pipe 200 is moved forward and backward or rotated, and the water stop of the pressurized water can be achieved permanently and effectively. This water stop rubber 123 is an embodiment of the seal referred to in the present invention. In addition, the side attached to the rotary body 124 of the water stop rubber | gum 123 incorporates the steel ring which reinforces this side. Accordingly, when the drill pipe 200 is moved forward and backward and the outer diameter 221 of the tool joint portion 220 having a diameter larger than that of the pipe body portion 210 of the drill pipe 200 is crimped to the inner diameter 1231 of the water stop rubber 123, A gap is prevented from being generated between the rubber 123 and the rotating body 124.

  The closing portion 120 is also provided with a relief valve 127, a pressure gauge 128, and a ball valve 129.

  The relief valve 127 provided in the closing portion 120 automatically opens the valve when the pressure rises rapidly due to clogging of sewage or earth and sand in the manifold 121 and the ball valves 1221, 1222, 1223, and 1224. It is a valve for escaping.

  The pressure gauge 128 provided in the closing part 120 is a measuring instrument that measures the pressure in the underground hole.

  The ball valve 129 provided in the closing portion 120 is a valve provided for connecting various devices, and is normally closed. The ball valve 129 is provided in the vicinity of the water-stopping rubber 123. For example, when digging waste or earth and sand accumulates in the vicinity of the water-stopping rubber 123, the ball valve 129 is opened to open the digging waste or earth and sand. Is removed.

  According to the underground hole excavating apparatus 100 of the present embodiment, the four ball valves 1221, 1222, 1223, and 1224 provided in the closing portion 120 that closes the inlet of the underground hole to be excavated are used to cover the water-containing layer. By applying a back pressure against the pressure of the pressurized water, the pressure of the pressurized water and the back pressure can be balanced. Thereby, it is avoided that the pressurized water coming out of the hydrous layer flows into the underground hole, and the underground hole can be excavated while preventing the drilling fluid from being diluted with the pressurized water. Moreover, by avoiding the outflow of the pressurized water from the water-containing layer, it is also possible to prevent the earth and sand from being ejected into the underground hole with the outflow of the pressurized water. Therefore, even if it adheres to the hydrous layer with the pressurized water, it is effectively prevented that the excavation of the underground hole is hindered by the outflow of the pressurized water from the hydrous layer and the eruption of earth and sand accompanying this.

  Next, an embodiment of the underground hole excavation method of the present invention will be described.

  In excavating the underground hole using the drill pipe 200, the conductor pipe 110 is inserted into the entrance of the underground hole.

  Next, the drill pipe 200 having the nonmagnetic collar, the mud motor, and the excavation bit attached to the tip in this order is passed through the water stop rubber 123 provided in the closing portion 120 of the underground hole excavation apparatus 100.

  Next, a closing portion 120 in a state where the drill pipe 200 is passed through the water-stopping rubber 123 is connected to the conductor pipe 110 inserted into the underground hole entrance, thereby closing the underground hole entrance.

  Thereafter, the drilling fluid is injected into the starting point of the drill pipe 200 using a high-pressure pump (not shown). As a result, the mud motor is rotated, and the rotation is transmitted to the excavation bit to excavate the underground hole. The drill pipe 200 is drilled into the underground hole while sequentially adding and rotating the drill pipe 200 around the axis as necessary. In addition, when not sticking to the water-containing layer with the pressurized water, all the four ball valves 1221, 1222, 1223, and 1224 are in a fully opened state.

  During excavation of the underground hole, an operator monitors the pressure gauge 128. Then, when the pressure gauge 128 confirms that the pressure in the underground hole has increased during excavation of the underground hole, it is determined that it has stuck to the water-containing layer accompanied by the pressurized water, and the four ball valves 1221 and 1222 are once set. , 1223, 1224 are closed. Then, the pressure gauge 128 measures the pressure of the pressurized water from the water-containing layer.

  Thereafter, the injection pressure of the drilling fluid is increased in the high-pressure pump, and another ball valve is opened while the ball valve corresponding to the pressure of the pressurized water from the water-containing layer is closed to counter the pressure of the pressurized water. Apply back pressure.

  Then, the excavating fluid of the same amount as that of the excavating fluid injected while balancing the pressure of the pressurized water from the hydrous layer and the back pressure is excavated while discharging from the underground hole to the outside of the underground hole.

  According to the excavation method of the underground hole of this embodiment, it is avoided that the pressurized water coming out of the hydrous layer flows out into the underground hole, and the excavating fluid is prevented from being diluted with the pressurized water. A borehole can be drilled. Moreover, by avoiding the outflow of the pressurized water from the water-containing layer, it is also possible to prevent the earth and sand from being ejected into the underground hole with the outflow of the pressurized water. Therefore, even if it adheres to the hydrous layer with the pressurized water, it is effectively prevented that the excavation of the underground hole is hindered by the outflow of the pressurized water from the hydrous layer and the eruption of earth and sand accompanying this.

  In the above-described embodiment, the back pressure applying unit according to the present invention has been described as an example of a ball valve. However, the back pressure applying unit according to the present invention is not limited to this, for example, a pinch. It may be a valve or a combination of a ball valve and a pinch valve. If a pinch valve is used, it can be avoided that the valve is clogged with foreign matter. Further, in the case of a combination of a ball valve and a pinch valve, a relatively rough adjustment can be performed with a ball valve, and a relatively fine adjustment can be performed with a pinch valve.

  Further, in the above-described embodiment, the example in which the closing part referred to in the present invention is connected to a conductor pipe inserted into the entrance of the underground hole has been described, but the closing part referred to in the present invention is It is not restricted to this, For example, you may connect with a casing pipe. The casing pipe is a bare pipe for the purpose of maintaining the hole wall, preventing fluid movement between the ground layers with different pressures, and reducing the hole wall resistance of the drilling drill pipe when excavating long-distance underground holes. A pipe inserted into a hole.

DESCRIPTION OF SYMBOLS 100 Underground drilling device 110 Conductor pipe 120 Closure part 121 Manifold 1221,1222,1223,1224,129 Ball valve 123 Water stop rubber 1231 Inner diameter 1232 Outer diameter 124 Rotating body 1241 Bolt 125 Bearing 126 126 Tube 127 Relief valve 128 Pressure Total 200 Drill pipe 210 Tube part 220 Tool joint part 211, 221 Outer diameter 300 Drilling port water stop device 310 Elastic seal

Claims (2)

  When drilling an underground hole using a drill pipe, when it is attached to a water-containing layer, it is sprayed from the nozzle of a drill bit provided at the tip of the drill pipe through the inside of the drill pipe and passes through the outer peripheral passage of the drill pipe. While increasing the injection pressure of the drilling fluid discharged through, and applying a back pressure against the pressure of the pressurized water from the water-containing layer to the discharge portion of the drilling fluid, the pressure of the pressurized water and the back pressure The excavation method of the underground hole characterized by excavating while balancing. Provide a closing part that closes the entrance of the underground hole drilled with a drill pipe,
(A) a back pressure application unit that applies a back pressure against the pressure of the pressurized water from the water-containing layer to the drilling fluid discharge unit; and (b) the drill pipe penetrates and has a back pressure of the drilling fluid on the outer diameter. A drilling device for underground holes comprising a seal having a mechanism for allowing the drill pipe to advance and retreat into the underground hole and rotating integrally with the drill pipe. .

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