JPH07100931B2 - Method for creating ground hardening layer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a method for forming a hardened ground layer used for improving soft ground, constructing foundations for structures, lining underground tunnels such as tunnels, and more particularly. Relates to an injection method in which an injection pipe provided with an injection nozzle on the tip side wall is inserted into the ground, a hardening material is injected at high pressure, and the surrounding soil is cut and stirred by the jet flow to form a hardening material injection layer.

[Conventional technology]

Conventionally, since the creation of a ground hardening layer by compaction filling using a high-pressure hardening material jet was proposed by Japanese Patent Publication No. 50-14803,
Rapid development has been achieved due to repeated developments in the curing agent surface, such as quick-setting curing material injection using a double pipe, compound injection with different types of curing agents, stepwise injection, etc. How to increase the distance is an eternal theme.
Therefore, the injection pressure has been dramatically increased to 200 to 600 kg / cm ² f, and air-encapsulated injection with a polymerization nozzle and pre-cleaning with fresh water injection have been developed.

[Problems to be solved by the invention]

Conventionally, as a means to extend the flight distance of the hardening material jet, the pressure of the hardening material jet itself is increased as described above, the jet is protected by air inclusion, and its pressure decay is prevented, or the surrounding soil is cleaned by pre-cleaning. Means have been taken to keep it in a state of good permeability. However, the hardening material jet is naturally viscous, and this has been an obstacle to increasing the pressure of the jet itself and extending the flight distance thereof. Especially when a hardening material having a high viscosity is used, the flight distance must be sacrificed, and in an extreme case, compaction filling injection itself is impossible.

[Means for solving problems]

In order to solve the above-mentioned problems, the present invention is directed to an injection pipe provided with a polymerization nozzle composed of a core nozzle and an annular nozzle surrounding the core nozzle on the tip side wall, and each flow passage communicating with each nozzle. Inserted to a predetermined depth of the ground, super high pressure water in the flow passage communicating with the nuclear nozzle, hardened material is pressure-fed into the flow passage communicating with the annular nozzle, respectively, and high-pressure injection from each injection nozzle, while the injection pipe is It is configured to retreat in a locus and mix the hardening agent into the surrounding soil while cutting and stirring the surrounding soil with a high-pressure jet to create a hardening layer. Is composed of a triple nozzle consisting of a core nozzle, an annular nozzle surrounding the core nozzle, and a surrounding nozzle surrounding the core nozzle, and super high-pressure water is provided in the flow passage communicating with the core nozzle, and a hardening material is provided in the flow passage communicating with the annular nozzle. Air each flow passage communicating with the nozzle is obtained so as to high-pressure injection and high-pressure pumping from respective injection nozzle.

[Action]

The ultra-high pressure water jetted from the nuclear nozzle has a low viscosity and a large mass, so it becomes a high-speed, high-pressure jet stream, and has high crushing force and flight distance. Since the hardening material jetted from the annular nozzle surrounding the nuclear nozzle has high viscosity and mass, the jet velocity will naturally be slow at the same pressure, but since the high-speed high-pressure ultra-high-pressure water jet penetrates the core, It is polymerized and accelerated, and the mass of the hardened material is also utilized in the direction of strengthening the crushing force. In addition, the voids perforated by the ultra-high pressure water jet are filled with the hardening material that has been entrained at the flow velocity by being pressed into the subsequent ultra-high pressure water jet, and then compacted and filled. Is created.

Furthermore, if a surrounding nozzle is provided and air is jetted, the diffusion of the hardening material jet from the annular nozzle to the outside is prevented and the film of the air jet with a low mass eliminates the friction between the soil and the jet, and further increases the flight force of the jet. Can be increased.

〔Example〕

An embodiment of a method for forming a hardened ground layer according to the present invention will be specifically described below with reference to the accompanying drawings. Reference numeral 1 denotes an injection pipe, and a crown 2 is attached to the lower portion of the injection pipe 1. The crown 2 is provided with a core nozzle 31, an annular nozzle 32 surrounding the core nozzle 31, and a polymerization nozzle 3 configured as a triple nozzle of a surrounding nozzle 33 surrounding the core nozzle 31, and each of the independent flow passages communicating with each other ( (Not shown) is configured inside. It should be noted that the nucleus nozzle 31 and the annular nozzle 32 surrounding the nucleus nozzle 31 are basically sufficient, but for convenience of explanation, the explanation will be given by adding the surrounding nozzle 33 as an example.

An excavating blade 4 is provided at the lower end of the crown 2, and an upper end thereof is connected to an injection pipe 1 having three flow passages which are connected to the flow passages in the crown 2 which are opened to the nozzles of the polymerization nozzle 3. At the upper end of the injection pipe 1, a swivel 5 to which an ultra-high pressure water pressure supply hose 51, a hardening material pressure supply hose 52, and an air pressure supply hose 53 are connected is attached.

The injection tube 1 is vertically supported by a driving device 6, and is rotated by the driving device 6 and can move up and down. In the present invention, the injection pipe 1 configured as described above is rotated by the drive device 6 at a predetermined position of the target ground A to insert a hole. Ultra high pressure water pressure supply hose 51, hardening material pressure supply hose 52, air pressure supply hose when inserted to a predetermined depth
From each hose of 53, while pumping the respective material to the injection pipe 1 at an ultrahigh pressure, the injection pipe 1 is rotated and each material is superposed from the nozzle 3 at the tip to be jetted to the side and raised to rotate. The soil around the ascending locus is stirred and mixed with a polymerization jet of a hardening material or the like to form a hardening layer B.

Although the embodiment has been described by forming a columnar hardened layer vertical in the vertical direction, in the case of tunnel lining, the injection pipe 1
Is supported in a horizontal direction and moves forward and backward, and the drive device 6 also has various forms, and in some cases it is not necessary to rotationally drive the injection tube 1. Moreover, the injection effect of the three materials can be changed by changing the injection pressures of the three materials as needed and making the injection pressures different.

〔The invention's effect〕

Since the present invention is configured as described above, it is possible to dramatically extend the flight distance of the hardening material jet, to form a hardening material injection layer having an extremely large diameter, and to achieve a high viscosity, which has been considered difficult until now. There is a feature that it is possible to inject a hardening material.

[Brief description of drawings]

The drawings show one embodiment of the apparatus according to the method for forming a ground hardening layer according to the present invention. FIG. 1 is a side sectional view showing a construction situation, FIG. 2 is an enlarged front view of a tip portion of an injection pipe, and FIG. [Fig. 4] is an enlarged side view of a tip portion of an injection pipe showing an injection state. 1 ... injection pipe, 2 ... crown, 3 ... polymerization nozzle, 31
…… Nuclear nozzle, 32 …… Annular nozzle, 33 …… Surrounding nozzle,
4 ... excavating blade, 5 ... swivel, 51 ... super high pressure water pressure hose, 52 ... hardening material pressure hose, 53 ... air pressure hose, 6 ... drive device, A ... target ground, B ... … Hardened layer,
a: Ultra-high pressure water jet, b: Hardener jet, c: Air jet

Claims (2)

[Claims] 1. A polymerization nozzle comprising a core nozzle and an annular nozzle surrounding the core nozzle is provided on the tip side wall, and an injection pipe having a flow passage communicating with each nozzle is inserted to a predetermined depth of the target ground. Ultra-high pressure water is sent to the flow passage communicating with the nuclear nozzle, and the hardening material is sent under high pressure to the flow passage communicating with the annular nozzle, and high-pressure injection is performed from each injection nozzle. A method of forming a hardened layer of ground, characterized by mixing a hardening agent into the surrounding soil while cutting and stirring the surrounding soil with a high-pressure jet. 2. The polymerization nozzle is constituted by a triple nozzle of a core nozzle, an annular nozzle surrounding the core nozzle, and a surrounding nozzle surrounding the core nozzle, and the flow passage communicating with the core nozzle is connected to the ultra-high pressure water and the ring nozzle. The method for producing a ground hardening layer according to claim 1, wherein the hardening material is supplied to the flow passage and the air is sent under high pressure to the flow passage communicating with the surrounding nozzle so as to be injected at high pressure from each of the injection nozzles.