JPH0462226A - Method for measuring level of underwater concrete - Google Patents

Abstract

PURPOSE:To improve measuring precision by setting a bottomed pipe with pressure sensors set at specified intervals on the internal and external surfaces of the tip section, in non-solidified concrete, and by finding the level of the placed surface with the arithmetic operation of the measured values of the four sensors. CONSTITUTION:On an internal and external surface near the tip of a bottomed pipe 6, at specified intervals, external pressure sensors 1, 2 and internal pressure sensors 3, 4 are arranged to be confronted internally and externally with each other. Besides, on a tremie 8 for placing concrete under water, the pipe 6 is so vertically fitted that the upper surface of the pipe 6 communicates with liquid mud 7 via a wire gauze 10. After that, by the tremie 8, the concrete 5 is placed under the water, and the pressure of the concrete is measured with the sensors 1, 2, and the pressure of the liquid mud is measured with the sensors 3, 4. Then, with the arithmetic operation of the measured values by the four sensors, the upper side level is found. As a result, measuring precision can be improved.

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention is applicable to the position of the top of the poured concrete (the boundary between the underwater concrete and the muddy water above it) when concrete is poured underwater using the tremie method. This article relates to a method for measuring the level of concrete in water.

(Prior Art) In the tremie method, in order to appropriately control the lifting position of the tremie pipe, it is necessary to grasp the top level of the underwater concrete being placed as accurately as possible. For this reason, various measuring devices and (1) fixed methods have been developed, but the technology for measuring the top level of concrete by submerging multiple pressure sensors in muddy water and underwater concrete is disclosed in Japanese Patent Application Laid-Open No. 62-1999.
The one disclosed in Japanese Patent No. 59721 is known.

In the above-mentioned conventional technology, four pressure sensors are attached to a long rod-shaped casing at predetermined intervals in the longitudinal direction, and the casing is suspended from a cable and exposed to muddy water.

The casing is submerged almost vertically into underwater concrete, and the casing is raised and lowered so that it can be placed in any desired position, and the position can be measured from the length of the cable. The position of the casing is adjusted while comparing the outputs, and the upper two pressure sensors are located in muddy water, and the lower two pressure sensors are located in concrete. The concrete top level is known from the position of the casing at this time.

(Problems to be Solved by the Invention) In the prior art described above, it is not possible to measure the top level with the casing properly submerged in concrete. A situation must be created in which the sensor is in muddy water and the lower two sensors are in concrete, and the casing must be raised as the top of the concrete rises to maintain this state at all times.

Furthermore, if the distance between the sensors is increased, the casing positioning operation described above becomes easier, but the measurement accuracy deteriorates. If you try to improve accuracy by reducing the sensor spacing, the measurement operation becomes difficult.

This invention was made in view of the conventional problems mentioned above, and its purpose is to accurately measure the top level of concrete by simply submerging a measuring device (corresponding to the casing) at an appropriate position in muddy water and concrete. The goal is to make it measurable.

(Means for Solving the Problems) Therefore, in the present invention, as shown in FIG. The upper end side is opened into the muddy water 7 on the concrete 5 to fill the pipero with muddy water, and two external pressure sensors 1 and 2 attached to the pipero at a predetermined interval in the longitudinal direction are used to In addition to measuring the pressure in the concrete 5, the pressure in the muddy water 7 in the pipe is measured using two inner pressure sensors 3 and 4 attached to the pipe at positions corresponding to the outer pressure sensors 1 and 2. The top level of the concrete was determined by calculating the measured values of these four pressure sensors 1, 2, 3, and 4.

(Function) As shown in Figure 1, the distance from the surface of the muddy water 7 to the concrete top is x1, the distance from the positions of pressure sensors 1 and 3 to the concrete top is y1, and the distance from pressure sensors 1 and 2 (3 and 4) is
) spacing Z%J Specific gravity of water 7 a1 Specific gravity of concrete 5 b1 Measured values of each pressure sensor 1, 2, 3.4 P+
, P2 , Pl.

When P4 is assumed, the following equations hold true.

P1 profanity ax+by P2-ax ten b (y-z) Pl = a (x 10 y) P4 arrogance a (x+y-z) The following equation is obtained by solving the above four simultaneous equations.

P, -Pl zP3　　　　　　　　Pl　-p.

Pl +P4 PI -P2 -Pl -P4 Since the sensor installation interval Z is known, the concrete top level X or y can be found by simple calculation of the pressure measurement values P+, P2, Pi, and Pa of each sensor. I can do it.

(Example) Figure 2 shows a situation in which the underwater concrete level measurement method of the present invention is applied to the tremie method of continuous underground walls.

The tremie pipe 8 is installed almost vertically in the muddy water 7 of the trench where a continuous underground wall is to be constructed, and is maintained at an appropriate height.
Concrete is poured into the muddy water 7 from the bottom end. 5 is the underwater concrete that has been placed.

The above-mentioned pipro used in the measuring method of the present invention is attached to the side of the tremie tube 8 via a bracket 9 in parallel with the tube 8, and is placed along with the tremie tube 8 almost vertically in the muddy water 7 and the concrete 5. .

A fine wire mesh 10 is attached to the upper end opening of the pipero to prevent concrete from entering the pipero and to fill the pipero only with muddy water.

The outer pressure sensors 1 and 2 are mounted on the outer surface of the lower end of the pipro.
is attached, and inner sensors 3 and 4 are installed on the inner side.
is installed. The outputs of these sensors 1 to 4 are introduced to a display device 12 on the ground through a sensor cable 11. The above-mentioned concrete top level y (Fig. 1) is determined by the arithmetic circuit of the display device 12, and a known constant value is added to the y to calculate the distance from the lower end of the tremie pipe 8 to the concrete top. , for example, is displayed on a bar graph type display.

In the embodiment shown in FIG. 2, a plurality of proximity switches 13 are attached to the side surface of the lower end of the pipro at predetermined intervals in the longitudinal direction. The proximity switch 13 does not turn on in muddy water 7, but turns on when entering underwater concrete 5. The output signals of these proximity switches 13 are also input to the display device 12, and it is determined from the outputs of the proximity switches 13 whether or not all of the pressure sensors 1 to 4 are in the underwater concrete 5. The top level when the sensors 1 to 4 are not in the concrete 5 is detected from the output of the proximity switch 13 and displayed.

(Effects of the Invention) As explained in detail above, in the method of the present invention, if the parts of the four pressure sensors attached to the pipes are submerged to appropriate positions in the underwater concrete, the positions of the pressure sensors can be used as reference points. It is possible to accurately measure the concrete top level based on the concrete top level or the muddy water level, and even if the top level rises with concrete pouring, the pipe does not need to be raised accordingly. In principle, there is no need to perform the troublesome measurement operation of adjusting the position of the measuring device (casing) up or down to find the top level, as in the past.

[Brief explanation of drawings]

FIG. 1 is a diagram explaining the principle of the measuring method of the present invention, and FIG. 2 is a schematic diagram of an embodiment in which the method of the present invention is applied to the tremie construction method. 1.2...Outer pressure sensor 3.4...Inner pressure sensor 5...Underwater concrete 6...Pipe 7...Muddy water 8 ...Tremmy tube 9...Bracket 10...
Wire mesh 11...Sensor cable 12...Display device 13...Proximity switch 1st! iiQ

Claims (1)

[Claims] A pipe with a closed bottom is placed almost vertically in unsolidified concrete cast in water, and the upper end of this pipe is opened into the muddy water above the concrete, so that the inside of the pipe is filled with muddy water. , two external pressure sensors installed on the pipe at predetermined intervals in the longitudinal direction measure the pressure in the concrete, and two external pressure sensors installed on the pipe at positions corresponding to the external pressure sensors. A method for measuring the level of underwater concrete, in which the pressure in the muddy water inside the pipe is measured by an inner pressure sensor, and the top level of the concrete is determined by calculating the measured values of these four pressure sensors.