JP3886465B2 - Ground hardening layer construction method and equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a ground hardened layer construction method and an apparatus therefor, in which a ground hardened material is formed by injecting a ground hardened material into a target ground for the purpose of strengthening support of a built foundation ground or stabilizing the ground and stopping water.
[0002]
[Prior art]
Conventionally, ground hardener injection for ground lining support, reinforcement support, or hardener layer construction for the purpose of water stoppage has been achieved by extending the reach of the hardener jet as much as possible to form a large diameter hardener layer. Various methods have been devised with ideal creation, and one of them is a method of extending the reach distance by encapsulating and protecting the hardener jet with air using a polymerization injection nozzle consisting of a core nozzle and an annular nozzle surrounding it. (For example, see Patent Document 1).
[0003]
Furthermore, prior improvement by the clear water jet is performed prior to the hardener jet, and the effective range of the hardener jet is extended (see, for example, Patent Document 2), or surplus slime is sucked by a suction mechanism (see, for example, Patent Document 3). Means have been taken to improve breathing.
[0004]
In addition, it has been often carried out by entraining the hardener injection with air and encapsulating the hardener jet as described above and airlift lifting and discharging of the cutting slime, but if necessary from the top of the rod Openings were sequentially provided in the air flow path, and the injection pressure decreased toward the lower part.
[0005]
The injection of the hardener requires downward injection at the rod insertion stage and side injection at the injection tube rod stage, so switching from below to side injection is necessary, but initially it was biased upward by the spring. A method of lowering the differential pressure valve to close the lower injection port (see, for example, Patent Document 5) has been adopted.
[0006]
However, since such a differential pressure valve is provided in the hardener flow path, a reliable operation cannot be expected due to, for example, the hardener adhering to the spring. Therefore, the steel ball is dropped into the material supply path to close the lower path ( For example, refer to Patent Document 4) and means for switching the injection have been taken.
[0007]
[Patent Document 1]
Japanese Patent Publication No. 7-100931 [Patent Document 2]
Japanese Patent No. 2865653 [Patent Document 3]
Japanese Patent Publication No. 6-29506 [Patent Document 4]
JP 2001-288734 A [Patent Document 5]
Japanese Patent Publication No. 48-13657 [0008]
[Problems to be solved by the invention]
The air supplied from above through a plurality of openings loses pressure due to the injection at the upper position as described above, and cannot secure a desired injection pressure at the lower part, causing unevenness in the combined injection and the depth. There is a problem that the cutting length decreases because the air cannot be smoothly encapsulated as the height increases.
[0009]
In addition, if a plurality of injection nozzles are set at the same plane position on the side of the injection rod, the injection pressures interfere with each other to reduce the effect, while a plurality of ground hardening materials are redundantly injected into the same plane portion. In addition, there is a problem that a hardened material layer having a thickness cannot be formed unless a lifting operation is added to the rotation operation.
[0010]
Furthermore, since the diameter of the conventional injection rod is the same from the top to the tip, there is no room for clearance between the rod insertion hole of the ground and the outer periphery of the rod. The pressure was consumed more than necessary.
[0011]
Furthermore, the method of closing the lower path by dropping the steel ball for switching from the lower side to the side injection cannot be applied unless a vertical drop channel is secured to the closing valve hole.
[0012]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention provides an air that distributes air to the surrounding area of the polymerization injection nozzle in a monitor section that is located below the plurality of polymerization injection nozzles provided on the tip side wall of the injection rod. A pressure accumulating part is provided so that air distributed to the polymerization injection nozzle surrounding part is accumulated and stored in the accumulating part from the supply path, and homogenized air injection is performed from a plurality of openings. did.
[0013]
In addition, a fresh water injection nozzle is provided at a predetermined interval above the plurality of polymerization injection nozzles so that advance improvement of the target ground is performed prior to injection of the hardener, and fresh water is supplied to the fresh water injection nozzle. In addition, the path for supplying the jet water from the jet hole at the tip of the rod is provided with a differential pressure valve at the tip of the rod tip of the supply path consisting of a clearance formed by sewing the polymerization injection nozzle and the air pressure accumulator, to supply fresh water The rod tip ejection part can be automatically opened and closed by changing the pressure.
[0014]
Furthermore, the setting positions of a plurality of superposition injection nozzles provided on the tip side wall of the injection rod are shifted up and down so as to be provided in a multistage radial manner, and the hardening material is injected simultaneously into the target ground area corresponding to the multistage vertical width, and the rod is raised. A thick curing material injection corresponding to a multi-stage vertical width can be performed without frequent operation.
[0015]
In addition, the outer diameter of the tip monitor section is configured to be larger than the outer diameter of the upper rod main pipe, and the difference between the outer diameter of the tip monitor section and the outer diameter of the rod main pipe is the difference between the rod insertion hole on the ground and the outer circumference of the rod. In order to prevent the occurrence of breathing and the exhaustion of the injection pressure.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. 1 is an injection rod, which is composed of a triple tube as a whole, and a plurality of superposition jet nozzles 2, 2,... Are set on the tip side wall in a multistage radial manner with the central portion shifted up and down by about 1.5 to 2.5 cm. A fresh water injection nozzle 3 is provided at a predetermined interval in the upper part.
[0017]
The superposition jet nozzles 2, 2,..., And the fresh water jet nozzle 3 are set in the monitor portion A that constitutes the rod tip and incorporates the injection mechanism, and the outer diameter thereof is larger than the outer diameter of the upper rod main pipe B. It is configured to have a diameter, and a clearance is formed between the inner wall of the rod main pipe B and the insertion hole C by insertion excavation of the monitor unit.
[0018]
The superposition spray nozzles 2... Each have a core nozzle 21 at the center, and surrounding nozzles 22... Are surrounded by rods separated from each other via a swivel 11 and communicated with the spray material tank. Communicate with the flow path.
[0019]
The jet flow from the superposition jet nozzles 2... Set in a multi-stage radial form is an interval that slightly interferes in the outer peripheral area at the above interval, but does not directly interfere because the opening direction is different.
[0020]
As described above, the rod 1 is composed of a triple tube as a whole, an air supply path 12 in the center, an annular hardener flow path 13 on the outer periphery, and a fresh water flow path 14 on the outer periphery. An air pressure storage unit 4 such as a receiver tank is set at a terminal of the air supply path 12 via a check valve 41.
[0021]
The air pressure storage unit 4 is provided with air flow passages 42 communicating with the surrounding nozzles 22... At the upper side, and check valves 43 are provided respectively to prevent backflow from the surrounding nozzles 22. It has become.
[0022]
By configuring the air accumulator 4 in this way, air corresponding to the accumulated pressure in the accumulator tank is uniformly supplied without flowing back to the flow path 42, so that injection efficiency close to atmospheric pressure can be obtained. A smooth airlift effect can also be obtained for the lifting of slime.
[0023]
The fresh water flow path 14 is constituted by the outermost clearance and opens to the fresh water injection nozzle 3 in the middle, but passes through the opening of the hardening material flow path 13 and the outer space of the air pressure storing section 4 and the tip of the rod 1. The differential pressure valve 31 set in the ejection hole 15 is opened and closed by adjusting the fresh water supply pressure.
[0024]
The differential pressure valve 31 is urged upward by a spring 32 and normally opens the ejection hole 15. As a result, drilling water is ejected from the ejection hole 15 while drilling down, and when the predetermined depth is reached, the fresh water supply pressure is increased. When the pressure rises above a certain level, the pressure descends against the urging force of the spring 32 and closes the ejection hole 15.
[0025]
In addition, air is supplied to the air pressure storage unit 4 during downhole drilling and drilled while injecting air from the surrounding nozzles 22... Thereby protecting the nozzle 22 injection port and improving the surrounding soil in advance. Can contribute.
[0026]
The fresh water in the fresh water flow path 14 is accumulated by the blockage of the ejection hole 15, and is injected as a high-pressure jet from the fresh water injection nozzle 3 to cut and agitate the surrounding soil, and the hardening material jet from the polymerization injection nozzle 2 set at the lower part. In addition to extending the reach distance, the mixing of the hardener and the surrounding soil is promoted to create a foundation for the formation of a homogeneous hardener injection layer.
[0027]
The rear end of the injection rod 1 is a swivel mechanism 11, which is connected to a corresponding portion of each flow path in the rod and a hose 7 connected to the injection material tank, and is operated on the base 5 Supported by mechanism 6.
[0028]
The hardened layer forming apparatus configured as described above first supplies lubricating fresh water to the flow path 14 and discharges it from the injection nozzle 3 and the tip injection hole 15, and advances with respect to the injection rod 1 by the injection rod operating mechanism 6. An operation such as rotation is applied, and the injection rod is inserted into the target ground G by the rotation of the excavating blade 8 and the injection rod 1.
[0029]
In this way, the injection rod 1 is propelled and inserted toward the target ground G, and when the predetermined depth is reached, the fresh water supply pressure to the flow path 14 is increased and the differential pressure valve 31 is lowered to close the tip ejection hole 15; Injected from the nozzle 3 as a high-pressure jet having a discharge amount of 50 to 80 liters per minute.
[0030]
Furthermore, cement milk as a ground hardening material is pumped into the flow path 13 at a pressure of about 300 kg / cm ² or more as a discharge amount of 300 to 600 liters per minute, and is injected from the polymerization injection nozzle 2. To do.
[0031]
The air supplied to the air supply passage 12 as described above is accumulated in the air accumulator 4 and supplied from the air passage 42 to the surrounding nozzles 22... Is done.
[0032]
In this way, by supplying the spray material to each nozzle and stepping up and retreating in the extraction direction while rotating the injection rod 1, each high-pressure jet perforates and cuts the surrounding particles to crush the soil particles. A hardened material injection layer X is formed in a cylindrical shape on the ground G along the drive locus of the injection rod 1.
[0033]
Since the present invention is configured as described above, a homogeneous air jet can be formed around the plurality of polymerization injection nozzles, and the plurality of polymerization injection nozzles are set in a multistage radial manner on the rod and set at the top. By adding fresh water cutting with a fresh water nozzle and greatly increasing the discharge amount of ground hardening material, it has been possible to smoothly operate the uniform air distribution, which has been a problem in conventional deep injection. .
[0034]
The injection layer X formed in this way is formed with the same injection layer in the portion of the injection layer adjacent to the injection layer X as necessary, and is arranged adjacent to each other in parallel to form a predetermined ground hardening layer. Will be created.
[0035]
[Brief description of the drawings]
FIG. 1 is an overall side view showing a construction situation according to an embodiment of the present invention. FIG. 2 is a longitudinal sectional side view showing a part of the structure of a main portion of an injection rod tip monitoring portion according to an embodiment of the present invention. 3] Similarly, enlarged side view of the nozzle setting part of the injection rod showing the appearance from the front of the polymerization injection nozzle [Explanation of symbols]
1 Injection rod
11 Swivel mechanism
12 Air supply path
13 Curing material flow path
14 Clear water flow path
15 Clear water injection hole 2 at rod end
21 Homogeneous nozzle
22 Surrounding nozzle 3 Shimizu injection nozzle
31 Differential pressure valve of fresh water outlet
32 Differential valve energizing spring 4 Air accumulator
41 Check valve for air supply line terminal
42 Air flow path from air reservoir to surrounding nozzle
43 Air pressure check part Air flow path check valve 5 Base 6 Injection rod actuating mechanism 7 Hose connected to the injection material tank B Rod monitoring part B Rod-main pipe C Rod insertion hole G Target ground X Hardening material injection layer

Claims (8)

Provided on the side wall of the tip part are a plurality of polymerization injection nozzles that inject ground hardening material from the core part and air from the surrounding part, and a fresh water injection nozzle is provided at a predetermined interval above the nozzle, and a lower part of the polymerization injection nozzle An injection rod provided with an air pressure accumulator for distributing air to the surrounding area of the superposition jet nozzle is inserted into the monitor section located at a predetermined depth of the target ground while jetting fresh water from the fresh water jet nozzle and the tip of the rod. While switching the supply fresh water from low pressure supply to high pressure injection at the depth, rotating the injection rod while injecting the high pressure ground hardening material from the core of the polymerization injection nozzle and the air accumulated by the air accumulator from the surrounding part A ground hardening layer construction method characterized by injecting ground hardening material into the target ground by retreating The ground hardening layer creation method of Claim 1 which provided the differential pressure | voltage valve in the rod tip ejection part of the supply path | route terminal which supplies fresh water to a fresh water injection nozzle. The ground hardened layer construction method according to claim 1 or 2, wherein the setting positions of the plurality of superposition jet nozzles are shifted up and down and provided in a multistage radial manner. The ground hardened layer construction method according to claim 1, 2 or 3, wherein the outer diameter of the tip monitor portion is configured to be larger than the outer diameter of the upper rod main pipe. A plurality of superposition nozzles on the side wall of the tip, an air supply path in the core of the injection rod provided with a fresh water spray nozzle at a predetermined interval above the top, and a plurality of superposition jet nozzles in the perimeter of the circumference A ground hardening material supply path to be joined to the opening, and a fresh water supply path to be joined to the fresh water injection nozzle at the peripheral portion thereof are set, and the multiple polymerization is performed on the terminal of the air supply path via a check valve upward. Set up an air pressure accumulating part that has a connection path that opens to each surrounding part of the injection nozzle, and provide a mechanism for switching the fresh water from low pressure supply to high pressure injection in the fresh water supply path. A ground hardened layer generating device supported by a drive mechanism provided 6. A ground hardened layer forming apparatus according to claim 5, wherein a fresh water injection hole opened and closed by a differential pressure valve at the end of the fresh water supply path and opened at the tip of the rod is provided. The ground hardened layer forming apparatus according to claim 5 or 6, wherein the setting positions of the plurality of superposition jet nozzles are shifted up and down and provided in a multistage radial manner. The ground hardened layer forming apparatus according to claim 5, 6 or 7, wherein the outer diameter of the tip monitor portion is configured to be larger than the outer diameter of the upper rod main pipe.

Images