JP3738495B2 - Concrete pouring method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a technique for improving a construction method in which concrete is pumped down and placed when an underground power plant, a tilt shaft, a shaft, or the like is constructed.
[0002]
[Prior art]
In recent years, there is a tendency to construct large-scale concrete structures deep underground. Among such concrete structures, for example, construction of inclined shafts and vertical shafts used for the conduits of underground hydroelectric power plants requires long ones of several hundred meters, and such concrete structures are constructed. When doing so, the concrete will be placed by pumping a very long distance downward.
[0003]
In such concrete pouring, if the concrete of the normal composition is simply supplied into the pipe and dropped and transported, the drop speed will be very large due to the low separation resistance and viscosity of the concrete, and it will be discharged from the discharge port. When released, material separation occurs.
[0004]
In order to solve such a problem, for example, Japanese Patent Publication No. 58-51110 discloses a concrete pipe connected to the lower part of a hopper capable of maintaining airtightness, and this pipe is connected to a rigid steel pipe, a flexible flexible hose, and the like. A concrete pouring method for concrete composed of is disclosed.
[0005]
According to the placement method disclosed in this publication, the flexible flexible hose interposed between rigid steel pipes has a valve function, so that the falling speed and dropping impact of concrete are alleviated, Concrete material separation is avoided.
[0006]
However, the concrete downward placing method disclosed in the official gazette has technical problems described below.
[0007]
[Problems to be solved by the invention]
That is, as disclosed in the official gazette, when the pumping line is composed of a rigid steel pipe and a flexible flexible hose, the dewatered state of the concrete tends to occur at these joints, and the concrete is dehydrated. Then, it becomes the cause of occlusion in the tube. When the blockage in the pipe occurs, the part is dismantled and the remaining concrete is processed, and the construction schedule is greatly shifted.
[0008]
In addition, in the placing method shown in the above publication, an airtight hopper is required, and concrete is supplied and placed intermittently in a lump, so that the overall structure becomes complicated and time is required for placing. There was also a problem that it took.
[0009]
The present invention has been made in view of such conventional problems, and the object of the present invention is to have a relatively simple structure that does not cause clogging in the tube and can be driven quickly. It is to provide a concrete pouring method for concrete.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a concrete pump via a concrete pumping pipe having one end connected to a pump for supplying concrete, a discharge port provided on the other end, and installed in an inclined state with a predetermined gradient. In the construction method of placing the concrete pipe downward, the concrete flow rate adjusting valve that flows down in the pressure feed pipe is installed in the vicinity of the discharge port to cope with a change in the slope length of the pressure feed pipe accompanying the concrete placement. Then, the discharge amount of the concrete is adjusted by the flow-down amount adjusting valve within the flow-down speed at which the material separation of the concrete does not occur.
According to this configuration, the concrete is continuously supplied in a state where the inside of the pressure feeding pipe is filled, and is placed in the vicinity of the discharge port with the flow rate adjusted by the flow rate adjusting valve. The flow velocity at this time is such that the material separation of the concrete does not occur.
The flow-down amount adjusting valve is provided on a flexible cylinder interposed so as to communicate with the pressure-feed pipe and an outer periphery of the cylinder, and pressurizes the cylinder to enlarge or reduce its inner diameter. And a pressure tank part to be configured.
According to this configuration, the structure of the flow amount adjusting valve is simplified.
The pump can adjust the supply amount corresponding to the pressure applied to the cylindrical body of the pressure tank portion.
According to this structure, the supply of the concrete with which a concrete pumping pipe is filled can be maintained appropriately.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the accompanying drawings. 1 to 7 show an embodiment of a concrete downward placing method according to the present invention.
[0012]
In the embodiment shown in the figure, the present invention is applied when constructing a conduit for an underground power plant. The conduit 10 has an inclined portion 10a having an inclination angle of about 50 ° and a total length of several hundred meters. And a horizontal portion 10b provided at the lower end of the inclined portion 10a, and a working laterality 11 extending horizontally from the middle of the inclined portion 10a is provided.
[0013]
As shown in FIG. 2, the water conduit 10 includes a circular cross-section inner pipe 12 and a rock wall surface excavated by providing a predetermined space portion 14 on the outer periphery of the inner pipe 12. Concrete is cast and filled inside.
[0014]
The concrete placement state shown in FIG. 1 has already been placed in a part of the horizontal portion 10b and the inclined portion 10a of the water conduit 10, and is about to be driven from about 1/4 of the inclined portion 10a toward the upper side. Installation is performed.
[0015]
As shown in FIG. 3, the concrete placing device has a pump wheel 18 disposed in the work side 11 and one end connected to the pump wheel 18 and extends to the inclined portion 10a through the work side 11. And a concrete pressure feeding pipe 20 provided.
[0016]
The concrete pressure feeding pipe 20 has a structure in which cylindrical steel pipes conventionally used are connected, and a flexible hose 22 is connected to the discharge port 20a on the tip side as shown in FIG. A flow amount adjusting valve 24 is provided in the vicinity of the discharge port 20a.
[0017]
As shown in detail in FIG. 5, the flow amount adjusting valve 24 has a cylindrical flexible cylindrical body 26 interposed so that the openings at both ends communicate with each other in the middle of the pressure feeding pipe 20, and the flexible flow rate adjusting valve 24. The pressure tank portion 28 is provided on the outer periphery of the flexible cylinder 26 and pressurizes the flexible cylinder 26 evenly from the outer periphery to expand and contract the inner diameter.
[0018]
The pressure tank unit 28 is connected to a hydraulic or pneumatic pressure supply source (not shown), and by applying oil or compressed air from these supply sources, pressure is applied to the flexible cylindrical body 26. Corresponding to the magnitude of the applied pressure, the cross-sectional area of the flexible cylinder 26 changes, and the amount of concrete flowing down this portion is adjusted.
[0019]
The pressure of the pressure tank section 28 of the flow amount adjusting valve 24 is controlled by the control device 30 shown in FIG. The control device 30 shown in the figure includes a pressure sensor 30a for detecting the pressure in the pressure tank section 28, a display 30b for displaying the pressure detected by the pressure sensor 30a, the output value of the pressure sensor 30a, and the pressure setting means 30d. And a control unit 30c that adjusts the supply of fluid to the pressure tank unit 28 based on the set pressure and controls the internal pressure to the set pressure.
[0020]
The control device 30 of this embodiment also controls the pressure pump 18a mounted on the pump car 18 based on the detected value of the pressure sensor 30a, and drives the pressure pump 18a to rotate. A control signal is sent to an inverter 18c connected to 18b, and the amount of concrete supplied from the pump 18a to the pressure feed pipe 20 is controlled.
[0021]
An example of control performed by the control device 30 will be described. First, in the concrete pouring as shown in FIG. 1, at the initial stage of pouring, the inside of the pressure feed pipe 20 laid in the inclined portion 10 a of the water conduit 10 is made to flow down about several hundreds of meters, and the discharge port Placing from 20a.
[0022]
However, as the driving progresses, the pressure-feed pipe 20 is gradually shortened, and when the driving site reaches the vicinity of the work lateral resistance 11, the driving pipe is driven at a flow-down distance of about several meters.
[0023]
That is, in the concrete structure which is the subject of the present invention, the concrete is cast at a wide flow distance of several hundreds to several meters, and no material separation occurs when such concrete is placed. There is a need to do.
[0024]
Therefore, the present inventors presuppose the use of high-performance concrete that is highly viscous and is unlikely to cause material separation. The amount of concrete was discharged and a simulation was conducted.
[0025]
The graph shown in FIG. 7 shows the simulation result at this time. In the simulation shown in FIG. 7, the diameter of the pressure feeding tube was set to 100 mm to 200 mm.
[0026]
Considering from this simulation result, for example, if it is attempted to always secure 100 cubic meters per hour during the placement period of the concrete discharge amount, the diameter of the pressure feeding pipe 20 is 150 mm when the flow-down distance is 150 m or more. However, when the flow-down distance is shortened, if the diameter is as it is, the discharge amount becomes too large, so it must be about 130 mm.
[0027]
In the present embodiment, in order to adjust the pressure of the pressure tank unit 28 in accordance with the change in the flow distance of the concrete based on such a simulation result, a predetermined pressure value corresponding to the change in the flow distance is a pressure. Input from the setting means 30d to the control unit 30c.
[0028]
In the control unit 30c, the current pressure value of the pressure tank unit 28 detected by the pressure sensor 30a is compared with the pressure value input from the setting unit 30d, and the pressure in the pressure tank unit 28 becomes the set value. To control.
[0029]
In this case, since the amount of discharge per hour is constant, the actual change in the flow-down distance can be obtained over time if the cross-sectional area of the space 14 into which concrete is filled and placed is known.
[0030]
Thus, when the pressure of the pressure tank portion 28 is adjusted to the set pressure, the diameter of the flexible cylindrical body 26 is adjusted by expanding and contracting, so that the discharge is always constant regardless of the change in the concrete flow distance. The quantity can be ensured without material separation.
[0031]
In this case, in this embodiment, the concrete is discharged from the discharge port 20a in a state where the inside of the pressure feeding pipe 20 is filled. In this state, when the diameter of the flexible cylindrical body 26 is reduced and the same amount of concrete is fed by the pumping pump 18a, the diameter of the flexible cylindrical body 26 changes, so the control unit 30c to the inverter 20c. The control signal is sent to the supply pressure from the pressure pump 18a so as to correspond to the set pressure.
[0032]
Now, according to the concrete pouring method performed as described above, the concrete is continuously supplied in a state where the inside of the pressure feeding pipe 20 is filled, and the flow rate adjusting valve 24 near the discharge port 20a. The flow speed is adjusted and cast, and the flow speed at this time is such that the material separation of the concrete does not occur.
[0033]
Therefore, the placement efficiency is improved as compared with the case where the concrete is simply placed and placed, and the pressure feeding pipe 20 is of a normal cylindrical shape and does not cause clogging in the pipe.
In the case of the present embodiment, the flow amount adjustment valve 24 is provided on the outer periphery of the cylindrical body 26 and the flexible cylindrical body 26 that is interposed so as to communicate with the pressure feeding pipe 20. , The pressure tank portion 28 that expands and contracts the inner diameter thereof is simplified, so that the structure of the flow rate adjusting valve 24 is simplified and the response of expansion and contraction is also accelerated.
Furthermore, in the case of the present embodiment, the pressure feed pump 18a adjusts the supply amount in accordance with the pressure applied to the cylindrical body 26 of the pressure tank portion 28, so that the concrete filled in the concrete pressure feed pipe 20 is filled. Can be kept in good condition.
[0034]
【The invention's effect】
As described above in detail in the embodiments, the concrete downward placing method according to the present invention has a relatively simple structure and does not cause clogging in the pipe, and can be placed quickly. Brief description of]
FIG. 1 is an explanatory diagram of a construction state of a concrete downward placing method according to the present invention.
FIG. 2 is a cross-sectional view taken along line AA in FIG.
FIG. 3 is an enlarged view of a part B in FIG. 1;
4 is an enlarged view of a portion C in FIG. 1. FIG.
FIG. 5 is an enlarged perspective view of a main part of FIG. 4;
6 is a block diagram of a control device used in the placing method of FIG. 1. FIG.
FIG. 7 is a graph showing a simulation result of downward placement of concrete.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Water guide path 12 Inner pipe 14 Space part 18 Pump car 18a Pressure feed pump 18b Drive motor 18c Inverter 20 Pressure feed pipe 20a Discharge port 24 Flow rate adjustment valve 26 Flexible cylinder 28 Pressure tank part 30 Control apparatus

Claims (3)

In the construction method in which one end is connected to a pump for supplying concrete, a discharge port is provided on the other end side, and the concrete is placed downward via a concrete pumping pipe installed in a predetermined inclined state,
A concrete flow rate adjusting valve that flows down in the pressure feed pipe is installed in the vicinity of the discharge port, and the discharge amount of the concrete is adjusted in accordance with the change in the length of the slope of the pressure feed pipe accompanying the placement of the concrete. The concrete pouring method, wherein the flow rate adjusting valve adjusts the flow rate within a flow rate at which the material separation of the concrete does not occur. The flow-down amount adjusting valve is provided on a flexible cylinder interposed so as to communicate with the pressure-feed pipe and an outer periphery of the cylinder, and pressurizes the cylinder to enlarge or reduce its inner diameter. 2. The concrete downward placing method according to claim 1, further comprising: a pressure tank portion that performs the following operation. The concrete downward placing method according to claim 2, wherein the pump adjusts the supply amount in accordance with the pressure applied to the cylindrical body of the pressure tank portion.

Images