JPS6153913A - Device and method of controlling flow rate-pressure for pouring of group - Google Patents

Abstract

PURPOSE:To prevent the occurrence of choking with cement, by a method wherein a control device for the number of revolutions of a pump is provided, and only a resistance means of a flow passage is located on a return passage, branched from a pouring route, running from a pouring pump to a ground to be poured, and returning to a grout source. CONSTITUTION:When, with a pouring pump 2 started, pouring of grout into the ground is started, the pump is driven until the number of revolutions is increased to a specified value by means of which a flow rate is increased to a given value till a time t1. When a ground becomes unacceptable and a pressure is gradually increased to a set value, a pressure is prevented against an increase as the number of revolutions of the pump 2 is decreased. By gradually decreasing a pouring amount, a pouring amount is decreased and a pressure is gradually decreased despite of a ground still having a room enough to allow pouring of the grout, but a nozzle 21 of a return passage 6 forms resistance to prevent decrease of a pouring pressure. Further, the number of revolutions of the pump 2 is decreased as a set pressure is regulated, and even if a pouring amount is finally decreased to zero at a time t3, return is continued for about 30min till a time t4, at which pouring is completed, to keep a pouring pressure at a specified value.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a device for measuring the injection flow rate and pressure in the ground, particularly in rock injection such as dam grouting.

(Prior art) Grout injection into bedrock takes a different form from injection into urban soft ground.In other words, as shown in Figure 3, grout is first poured at a set flow rate, and then from a certain point. The injection amount is gradually reduced until the injection amount is zero. On the other hand, the injection pressure gradually increases because the resistance of the ground to the ground increases with the injection.

When the injection pressure reaches the set pressure, the set pressure is maintained while decreasing the flow meter. Furthermore, this set pressure can be maintained even if the flow rate becomes zero.
You must do it for 0 minutes.

Conventionally, an injection method as shown in FIG. 4 has been used to maintain the injection flow rate and pressure. That is, when the grout in the tank 1 is injected into the target ground 4 via the injection v3 by the injection pump 2, a return path 6 that branches off from the injection path 5 and returns to the tank 1 is provided, and a fifth A return valve 7 shown in detail in the figure is provided, and the injection path 5
placed in the middle of t'1. Based on the signal from the flow rate/pressure detector 8, the return pulp 7 is fully adjusted to control the desired flow rate/pressure. 9 is a recording and flow rate/pressure controller; 10 is an injection pipe installation machine.

An example of the structure of the return valve 7 is shown in FIG.

To explain this in detail, a valve seat 71 made of rubber or the like is installed inside the casing 70, and a metal cone-shaped needle valve 73 is provided at the tip of a rotating rod 72 against the opening edge of the valve seat 71. It can move forward and backward while rotating. In order to advance and retreat the needle valve 73, a driven gear 74 is screwed into the rotating σ2 door 2, and a driving gear 76 connected to the output shaft of the rotary drive motor 75 meshes with the driven gear 74. ing. Furthermore, a three-way joint 78 is connected to the inflow lower 7, and a hose forming the return path 6 is connected to the outflow lower 8. The operation of the return valve 7 is controlled to a predetermined flow rate and pressure. Therefore, based on the signal from the flow rate/pressure detector 8, the rotary drive motor 75 rotates forward and reverse, rotates the rotary rod 72ft forward and reverse, and connects the opening edge of the door 1 and the needle valve 73. This is to adjust the gap between the outer surface of the

However, conventionally, this return valve 7 is constantly controlled during the injection operation.

Then, when the injection pressure gradually increases to or near the set pressure, the unit discharge amount from the injection pump 2 is always constant, so if the injection 1zr continues as it is, the pressure will exceed the set pressure, so the set pressure will increase. In order to maintain this, operations are performed to gradually increase the opening degree of the return valve 7, increase the return amount, and lower the injection pressure. However, if the injection fff is lowered, the injection pressure will fall below the set pressure.

Therefore, on the contrary, the opening of the return valve 7 is reduced by 1 degree to increase the injection pressure. The process in which the flow rate decreases in FIG. 3 is a process in which the needle valve 73 operates fM frequently. Near the end of injection, the gap between the needle valve 73 and the valve seat 71 is extremely small, and the cement grout fills this small gap with high pressure, for example 50 k as shown in Figure 3.
It passes through at a high pressure of g, /ffl and returns to evening 1 via return path 6.

On the other hand, one of the applicants had previously applied for patent application No. 59-30961.
As a general rule, an on-off valve and a nozzle are installed in the return path, and the rotation speed of the injection pump is controlled from the beginning of the injection until near the end.After that, the on-off valve is opened to fully start the return, and the nozzle is used as a resistance to maintain the specified pressure. We proposed a method to maintain this.

(Problem to be Solved by the Invention) Generally, the purpose of providing a II return path in the grout injection method into rock is to prevent cement paste from settling and solidifying within the injection hose. In particular, when cement grout passes under high pressure through the small gap between the needle valve 73 and the valve seat 71 at the end of injection tUt, not only the valve seat 71 but also the needle valve 73 and the casing 70 undergo severe wear, and this gl( Therefore, frequent disassembly, inspection, adjustment, etc., are required to keep it clean, which poses a problem that hinders smooth injection work.

Kon VC'! &, valve 7-1-71 and needle valve 7
I can't even think of revising the shape of item 3. For example, the needle valve 73 may be made elongated. However, the current situation is that even with this method, it is not very effective.

On the other hand, in the prior art, it is necessary to provide an on-off valve between the nozzle provided in the return path and the main flow path, and the grout flows through the return path for, say, 2 hours until the end of injection. do not have. As a result, it was found that between the branch point and the closing part of the on-off valve, the cement part of the grout may be deposited and block the return path. Attempts were made to prevent the cement from settling by installing a turbulent plate to generate turbulent flow and to apply the turbulent flow to the closing part, but no good results were obtained.

Therefore, the purpose of this proposal is to solve the above-mentioned conventional problems,
An object of the present invention is to provide a flow rate/pressure control system for grout injection that can effectively prevent cement clogging while at the same time effectively preventing wear of the device due to cement particles.

(Means for Solving the Problems) In order to solve the above problems, the present invention provides a system for controlling the injection amount and injection pressure when grout is injected into the target ground using an injection pump. In addition to installing a pump rotation speed control device that fully opens the rotation speed of the injection pump according to the set flow rate and pressure, the return path that branches from the injection path from the injection port to the target ground and returns to the grout source has a flow rate A flow rate/pressure control device for grout injection, which is characterized in that only a flow path resistance means is provided as a pressure adjustment means, sweeps the target ground. In the method of controlling the injection amount and injection pressure when injecting into the grout, a resistance means is provided in the return path branching from the injection path leading from the injection pump to the target ground and returning to the grout source, the resistance being constant during the entire injection process, Always! A method for controlling the flow rate and pressure in grout injection is also provided, which is characterized by controlling the injection amount and injection pressure by injection while performing one turn. In other words, the feature of the present invention is that The unit discharge volume of the injection pump was always constant, but the unit discharge volume of the injection pump was made variable by its rotation control, and the injection flow rate and pressure were controlled by rotation control, and the constant return method was adopted. By adopting this, it is possible to prevent cement from settling and solidifying in the flow path, especially in the return path, and to compensate for the pressure drop when the injection flow rate decreases by basically providing only a flow resistor in the return path. That's the runner-up.

FIG. 1 shows seven general factors of the present invention.According to the present invention, a rotation speed control device 20 for the infusion pump 2 is provided. In response to the current flow rate/pressure signal from the injection pump 2, the rotational speed of the injection pump 2 is controlled in accordance with the control pattern shown in FIG. 2 to maintain the set flow rate/pressure.

On the other hand, the return path 6 includes a nozzle 21 as a resistance means.
The aperture of the nozzle 213 in which No. 3 is provided is 1 [J
Depending on the injection flow rate and injection pressure of l, the injection flow h] and pressure 1li shown in FIG.
A material having a resistance value such that a 111i1tl pattern can be achieved is selected.

(Function) In the system of the present invention, the injection pump 2 is activated to start injection, and is operated at a substantially constant rotational speed to achieve a predetermined flow rate until time t1, as shown in FIG. As the injection progresses, the ground becomes harder to receive, and the pressure gradually rises.Then, this pressure becomes the set pressure (for example, 7.
5 kg/ffl) - While lowering the rotation speed of the injection pump 2, prevent the pressure from increasing by more than 7'L. As the amount of injection is reduced, the amount of injection becomes small, and the pressure gradually decreases, even though the ground has sufficient capacity to receive the grout. However, the return path 6 is provided with a nozzle 21, which acts as a resistance and prevents the injection pressure from decreasing. After that, the rotation speed of the injection pump 2 is lowered while maintaining the set pressure, and finally t
Even if the injection amount reaches zero at 3 o'clock, the return continues for about 30 minutes until completion at 4 o'clock, keeping the injection pressure constant.
During the period from t3 to t4, all of the grout is returned, and the resistance when passing through the hollow nozzle 22 becomes the set pressure and the grout is reduced.

As described above, according to the present invention, there is no need for conventional return pulp. In addition, stable injection pressure and flow rate control can be performed.

Embodiment FIG. 2 shows an embodiment of the resistance means used in the Mizumoto system.

The resistor means 21 shown in FIG. 29 are connected to the return path 6 of the system shown in FIG. The resistance means 21 includes a tubular connecting portion 210, a nipple portion 211 connected to the upstream side of the return path 6″, and a nipple portion 212 connected to the downstream side of the return path 6.Nipple portion 21
A blind board 21.1 is fixed to 1, and this blind board 21
A nozzle 213, which is the main body of the resistance means, is attached to the center of the 4. /7'l/-y”ll-Q+
”ll,-)1ril!+mTh&i&IA-ywmI
Then, the nipple part 211 and the nipple part 211 are replaced. On the other hand, the nipple part 212 has a blind plate 215 of the flow n state control instep.
is stuck. This blind plate 215 is connected to the connecting portion 21
This baffle plate is used to completely prevent erosion of the inner surface of the channel by the grout when the flow rate of the grout in the outlet is high, but it may be omitted depending on the case.

It goes without saying that the return path 6 may be provided with additional parts unrelated to flow rate/pressure adjustment.

(Effects of the invention) As described above, by keeping the return path in a constant state of flow, sedimentation and solidification of cement are prevented, and the return path is provided with only a nozzle as a resistor. Because of this configuration, the system line is extremely simple, and troubles such as clogging are unlikely to occur, and maintenance is also extremely easy.Also, since the only part that wears out is the nozzle, maintenance can be done indoors and at low cost. There are 3,

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of the present invention, Fig. 2 is a vertical cross-sectional view showing an example of the resistance means used in the present invention, and Fig. 3 is a diagram showing current/pressure control in rock grouting. 4 is an overview of a conventional system, and FIG. 5 is a sectional view of a conventional return valve. 2. Injection pump 3. Injection pipe 5. Injection route 6. Return path 8. Flow rate detector
20... Rotation speed control device 21... Resistance means 21
3...Nozzle% Applicant Front Engineer 1
1-ng Co., Ltd. Nittoku Construction Co., Ltd. Figure 2

Claims (2)

[Claims] (1) When injecting grout into the target ground using an injection pump, the device that controls the injection amount and injection pressure is equipped with a pump rotation speed control device that controls the rotation speed of the injection pump according to the set flow rate and pressure. , a flow rate/pressure control in grout injection characterized in that a return path branching from the injection path leading from the injection pump to the target ground and returning to the grout source is provided with only flow path resistance means as a flow rate and pressure adjustment means. Device. (2) When injecting grout into the target ground using an injection pump, in a method of controlling the injection amount and injection pressure, the entire injection process is performed by branching from the injection path from the injection pump to the target ground and returning to the grout source. Flow rate and pressure control in grout injection, characterized in that a resistance means with a constant medium resistance is provided, and the injection amount and injection pressure are controlled by controlling the rotation speed of the injection pump from the beginning of injection to the completion, while constantly returning. Method.