JPH07892B2 - Ground improvement method by ultra-high pressure mixed hardening agent jet and its equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to an instantaneous hardening agent that hardens the ground by mixing AB2 liquid, or by A liquid from a nuclear nozzle and gas ejected from a surrounding nozzle, or The present invention relates to a ground improvement method and an apparatus for injecting a mixture of a slow-curing hardener and a pressurized gas into the ground as an ultra-high pressure jet to improve the foundation of a structure and soft ground.

[Prior Art] Conventionally, many ground improvement methods using a hardening agent jet have been developed, but those using a high-pressure and high-speed jet use a slow-setting hardening agent exclusively, and a quick-setting hardening agent naturally Low pressure injection, which is close to injection, has been used. In addition, the injection pressure used for high-pressure injection is at most about 200 kgf / cm ² , and no aggressive injection device has been adjusted to handle injection pressures higher than that.

[Problems to be Solved by the Invention] One of the reasons why the instantaneous curing agent is not used for ground improvement by high-pressure injection is that the instantaneous curing agent is a two-liquid type, and two liquids must be mixed after injection. There was a point that it was hardened during the process and it became impossible to inject due to germination or block hardening.
Therefore, a slow-curing curing agent with a long curing time has been used for high-pressure injection, but since the curing time is long, there is a problem that the curing agent flows back and leaks from the injection port when the discharge amount is increased. did. In particular, the problem is large for those requiring a special injection angle such as in the horizontal direction or above, and high-pressure injection is almost impossible.

Another problem with high-pressure injection is that as the injection pressure is raised, the reaction force from the injection pressure of the nozzle is applied to the injection rod, causing a warp in the rod and a large amount of energy loss, and finally rotation. There is a problem that makes it impossible.

[Means for Solving the Problems] The present invention provides an ultra high pressure injection of 200 kgf / cm ² or more by providing an injection nozzle at the opposite side of the rod side wall to absorb the injection reaction forces from each other so as to have seismic resistance. By using an ultra-high pressure pump device that can prevent the wear due to the sliding friction of the pressure responder by filling the space between the cylinder and the valve chamber with a liquid having a specific gravity different from that of the pressure feed liquid as the pressure transmission medium of the piston. An output of up to 500 kgf / cm ² was secured. In addition, the injection nozzle is configured as a polymerization nozzle that superimposes at the outlet by the core nozzle and the surrounding nozzle, and two liquids of the instantaneous curing agent are instantaneously mixed at the nozzle outlet to inject ultra-high pressure with a high speed force exceeding the instantaneous curing time. In this case, or by simultaneously injecting the liquid A from the core nozzle and the gas from the surrounding nozzle, all the above problems are addressed.

[Operation of the Invention] As a specific example, when the liquids A and B, which exhibit instantaneous curing by mixing, are used, both the two liquids are separated from each other by the separation flow path, and the nuclear nozzle and the surrounding nozzle are superfluous. They are fed under high pressure and are entrained at a stretch in the superposition section to form a mixed jet.

The mixed jet flow cuts and agitates the surrounding soil according to the operation of the injection rod while absorbing the reaction force of the spine injection and forms a cylindrical hardened layer. When a one-component slow-curing curing agent is used as the liquid A, the curing agent and gas, for example, air, are pressure-fed to the core nozzle and the surrounding nozzle while being separated by the separation channel, and the surrounding nozzle separates the gas. , For example, by jetting air, the slow-curing curing agent jetted from the nuclear nozzle is blown away, and bubbles are generated by mixing with the liquid, and when the bubbles are broken, a dynamic bursting effect can be obtained, and a larger density is obtained. It is possible to form a thick columnar hardened layer. The hardened layers are arranged in parallel as necessary to improve the ground such as foundation ground formation, water stoppage, and soil retention.

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

Reference numeral 1 denotes an injection rod having divided flow paths 2a and 2b, which are respectively formed as nucleus nozzles 3a and 4a and surrounding nozzles 3b and 4b, which are superposed on the tip side wall, and constitute injection nozzles 3 and 4 at the opposite positions. The injection rod 1 is supported by a rotary propelling / retracting mechanism 5 for rotating and propelling and retracting it, and its rear end is a quick-setting ground hardening agent composed of two liquids in the separation channels 2a and 2b via a swivel 6. The supply hoses 6a and 6b for supplying the liquid, the liquid B, the loose-setting ground hardening agent, and the gas are connected. Supply hose
6a and 6b are connected to an ultra-high pressure pump device for sending a curing agent or gas under pressure. The ultra-high pressure pump device is composed of a piston cylinder, a valve chamber, and a pressure responder that transmits pressure from the cylinder chamber to the valve chamber.The pressure responder is made of an oil having a specific gravity different from that of the hardener liquid filled between the chambers. It is composed of such a liquid and an elastic film which responds accordingly. The filling liquid that constitutes the responder moves between the cylinder and the valve chamber by the volume change due to the piston operation, and the hardening agent liquid corresponding thereto flows into the valve chamber and is pumped by the opposite operation of the piston. During that time, the hardener liquid is sucked under pressure without contacting the diaphragm and the plunger due to the presence of the filling liquid, so that the wear due to sliding friction is prevented and the output is increased. The valve box is provided in each of the inlet passage and outlet passage leading to the valve chamber, the valve seat part is formed in a substantially hemispherical concave shape, and it corresponds to the valve seat and concave shape in which a plurality of small holes are formed in the axial direction from the concave surface. The valve body is composed of a spherical body and a spring that presses the valve body against the seat, and the operation of the spherical valve further promotes the improvement of pressure. It is more advantageous if the rotation propulsion / retraction mechanism 5 can freely change the rod propulsion angle and has a self-propelled function. An excavation blade 7 is provided at the tip of the injection rod 1, the valve 8 is opened, and the rod 1 is rotated while ejecting the lubricating liquid to propel it into the target ground M. When the predetermined depth is reached, the valve 8 is closed, the liquid A or the loose-setting ground hardening agent is pumped to the separation channel 2a, and the liquid B or the gas is pumped to 2b at an ultrahigh pressure, and the jet nozzles 3 and 4 rotate while jetting. The hardened layer S is formed in a cylindrical shape by retreating.

As a result of experiment on sandy soil with N value of 15 to 20, injection pressure is 40
0kgf / cm ² , discharge rate 100l / min, rotation speed 8R.PM, rising speed
A columnar hardened layer with a huge diameter of 3 cm and 70 cm at 2 cm / min was created.

Incidentally, as another embodiment, a configuration in which any one of the injection nozzles 3 and 4 can be appropriately closed by providing a control valve on the nozzle itself or by the ultra high pressure pump device itself connected to the supply hoses 6a and 6b. Can also be

[Advantages of the Invention] Since the present invention is configured as described above, it is possible to inject a curing agent at an ultrahigh pressure of 200 kgf / cm ² or more, and to use a two-component curing agent for an ultrahigh-speed injection to obtain a sufficient discharge amount. While pouring, there is an effect that a uniform and large-diameter cylindrical hardened layer can be formed without causing backflow leakage.

Further, in the case of gas, since injection can be performed at a pressure higher than that of a liquid, when the slow-curing curing agent consisting of one liquid is injected, it is included as a super-high pressure gas to prevent backflow leakage of the curing agent. In addition, it is possible to surely inject the curing agent further away, and to form a columnar cured layer having a high density due to the burst effect of the generated bubbles.

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention. FIG. 1 is a side view showing a construction situation, FIG. 2 is a vertical sectional view of a tip portion of an injection rod, and FIG. 3 is a horizontal sectional view of XX portion in FIG. It is a figure. 1 ... injection rod, 2a, 2b ... separated flow path, 3,4 ... injection nozzle, 3a, 4a ... nuclear nozzle, 3b, 4b ... enveloping nozzle, 5 ... rotational propulsion / retraction mechanism, 6 ... Swivel, 6a, 6b
…… Supply hose, 7 …… Drilling leg, 8 …… Valve, M ……
Target ground, S ... Cylindrical hardened layer

Claims (2)

[Claims] 1. An injection rod provided with injection nozzles, each of which communicates with a divided flow path and which is composed of a nuclear nozzle and a surrounding nozzle, which are superposed at an injection port, at the opposite position of the rod tip side wall, and is inserted into the target ground, To create a hardened layer by rotating and retracting the rod from the insertion part while simultaneously injecting the liquid A from the core nozzle and the liquid B or gas from the surrounding nozzle in the opposite direction at an ultrahigh pressure of 200 kg f / cm ² or more. A ground improvement method using an ultra-high pressure mixed hardening agent jet. 2. An injection nozzle constituted by a nuclear nozzle and a surrounding nozzle, each of which communicates with a divided flow path and overlaps at an injection port, is opened in an anti-reverse direction at a position opposite to the back of a rod tip side wall. A ground improvement device comprising an injection rod, in which one of the surrounding nozzles is closed, supported by a rotation propulsion / retraction mechanism, and an upper end of the rod is connected to a curing agent supply unit for supplying the curing agent to each of the divided flow channels via a swivel.