JPH04264228A - Underground subsidence measuring apparatus - Google Patents

Abstract

PURPOSE:To facilitate the forecasting of the total subsidence from the preceding subsidence caused before the reaching of a face by measuring a subsidence of a natural ground continuously as caused by the excavation of a tunnel. CONSTITUTION:A measuring tube 5 is buried into a natural ground 1 on a tunnel 2 and an insertion truck 10 on which a connecting pipe type subsidence meter 11 is mounted at a specified measuring interval is inserted into the measuring tube 5. When the natural ground 1 sinks, the subsidence meter 11 detects a change in the height with respect to a reference water surface of a reference water tank 12 to be sent to and recorded in a recorder 15 with an output cable led out of the measuring tube 5.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an underground subsidence measuring device for measuring subsidence of ground due to tunnel excavation.

0002

2. Description of the Related Art Urban tunnels are generally made of soft ground, have only a small amount of earth cover, and are often located close to some kind of structure.

[0003] For this reason, in addition to stability, such as the self-supporting nature of the face, the influence of displacement (subsidence, etc.) of the ground on above-ground or underground structures is always a problem when tunnels are excavated. In particular, loosening of the ground at the face may sometimes reach the ground surface.

[0004] Settlement is caused by a complex combination of various factors, but it is often caused by the stability of the face surface. These settlements can be significantly reduced by appropriate shoring and the use of auxiliary construction methods.

[0005] Therefore, if the final maximum settlement (total settlement) can be predicted in advance, excessive settlement can be prevented by taking measures in advance. The subsidence behavior of the ground surface in unconsolidated ground 1 with a small earth cover is generally shown in Figure 4.
As shown in FIG. 2, this subsidence phenomenon occurs due to loosening in front of the face 3 before the face 3 of the tunnel 2 arrives, and this subsidence phenomenon continues even after the face 3 has passed.

[0006] Therefore, the preliminary settlement S that occurs before reaching face 3
1 and the subsequent settlement S2 after the face advances, it becomes possible to predict the total settlement S by measuring the amount of settlement in front of the face 3.

[0007] To measure the advance settlement or total settlement,
It is possible to drill a hole on the tunnel route from the ground surface and bury the measuring device in advance, but installation is often difficult in urban areas due to various restrictions. Therefore, as shown in Fig. 5, from the entrance of tunnel 2 or vertical shaft 4 to
A method has come to be used in which horizontal boring is performed in the ground 1 directly above the ground, and the inclination angle of a measuring tube 5 buried in the borehole is measured with a mobile inclinometer 6 to determine the amount of settlement.

[0008]

[Problems to be Solved by the Invention] However, with the method of determining the amount of subsidence by measuring the inclination angle of the measuring pipe, (a) it is difficult to measure in real time, (b) the measurement work takes time, and (c) (d) It is dangerous to work at heights; and (e) It is not possible to provide warnings if necessary.

[0009] The present invention solves this problem in measuring the subsidence of the ground, and it is possible to measure the subsidence of the ground in real time. The purpose of the present invention is to provide an underground subsidence measuring device that is unnecessary, safe, and capable of issuing a warning when necessary.

0010

[Means for Solving the Problems] The present invention provides a measurement pipe buried underground, an insertion cart inserted into the measurement pipe over a predetermined measurement section, and a reference water tank for setting a reference water level for measurement. , a communication pipe connected to the reference water tank and laid on the insertion cart, a sinkage meter attached to the insertion cart at predetermined measurement intervals and connected to the communication pipes, and an output cable of this sinkage meter connected. The underground subsidence measuring device is composed of a recording device and a recording device.

[0011] When performing measurements, a measuring tube of the length necessary for the measurement is buried in a tunnel by boring, and an insertion cart is inserted and fixed into the measuring tube. The subsidence meter is connected to the reference water tank via a communication pipe, and when subsidence occurs, the height of the reference tank relative to the reference water level changes, so by measuring this change in height, the amount of subsidence can be continuously calculated. Detect. The detection data of the amount of subsidence is sent to a recording device and recorded.

[0012] Furthermore, an alarm device is provided that outputs an alarm when the detected value of the subsidence meter exceeds a predetermined subsidence limit value, so that when the subsidence limit value is exceeded, an alarm is issued so that countermeasures against subsidence can be taken immediately. There is.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an explanatory diagram showing the overall configuration of an embodiment of the present invention. Here, the measurement pipe 5 is a steel pipe or PVC pipe of about 125Φ and is buried in the ground 1 above the tunnel 2, and an insertion cart 10 is inserted into the measurement pipe 5 over the measurement section L. . Measurement section L is at least 100m
It is desirable to keep it at a certain level. Subsidence gauges 11 are attached to the insertion cart 10 at predetermined measurement intervals P, and each subsidence gauge 11 is connected to a communication pipe 13 whose one end is connected to a reference water tank 12 . An output cable 14 of the subsidence gauge 11 is connected to a recording device 15.

As shown in FIGS. 2 and 3, the insertion cart 10 has a mounting base 20 on which the subsidence gauge 11 is mounted, and each mounting base 20.
It is composed of a holding frame 21 for holding the measurement interval P at a predetermined measurement interval P, and rollers 22 for running. Bearing 23 of roller 22
is attached to the left and right slopes 24 at the bottom of the mounting base 20 so as to be rotatable about the rotation axis 25 in the radial direction of the measuring tube 5, and the insertion cart 10 tilts when inserted into the measuring tube 5. Even if it occurs, it will return to horizontal due to its own weight. In addition, the insertion cart 10 includes an injection hose 2 for injecting mortar.
6 is installed, and can be filled after insertion.

The recording device 15 includes a regulator 30 installed near the measurement site and a data logger body 3 installed in the office.
1, a plotter 32, and a printer 33, and alarms 34 and 35 are connected to the regulator 30 and the data logger main body 31.

The subsidence gauge 11 is a small-capacity water pressure gauge, and when the height of the subsidence gauge 11 based on the reference water level WL of the reference water tank 12 changes due to subsidence, the change in water pressure due to this height change is detected electrically. is detected, and the output cable 14 connects the regulator 3.
Send to 0. The regulator 30 A/D converts the analog signal sent from the subsidence meter 11 and sends it to the data logger main body 31. The data logger body 31 is a computing logger equipped with a CPU and memory, and calculates the amount of subsidence by calculating the digital signal of the water pressure change sent from the regulator 30, and operates the plotter 32 and printer 33 to graph it. and output as characters. Furthermore, based on the relationship between the preceding settlement S1 and the subsequent settlement S2, the state of subsidence of the ground 1 can be simulated from the data of the preceding settlement S1, and the total settlement S can be determined in advance.

The regulator 30 and data logger main body 31 are
Each subsidence limit value can be set in advance, and the subsidence meter 1
If the detection value of 1 exceeds the set subsidence limit value, alarm 3 will be activated.
Send a signal to 5 and 36 to issue an alarm.

[0018]

[Effects of the Invention] As explained above, the underground subsidence measurement device of the present invention can measure the subsidence of the ground in real time, so it can predict the total subsidence in advance based on the preceding subsidence and prevent excessive settlement. Subsidence can be prevented. In addition, it is safe because there is no need to set up special work scaffolding and work at heights during measurement, and it is possible to issue an alarm to the work site and office as necessary.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the overall configuration of an embodiment of the present invention.

2 is a partial longitudinal sectional view of the measuring tube of FIG. 1; FIG.

FIG. 3 is a cross-sectional view of the measuring tube of FIG. 1;

FIG. 4 is an explanatory diagram showing the relationship between progression and subsidence of a tunnel face.

FIG. 5 is an explanatory diagram of a conventional subsidence measuring device.

[Explanation of symbols]

1. Grounds 2 Tunnel 3 Face 5 Measurement tube 10 Insertion trolley 11 Settlement meter 12 Standard water tank 13 Communication pipe 14 Output cable 15 Recording device L Measurement section P Measurement interval S1 Preceding subsidence S2 Subsequent subsidence S Total subsidence WL Standard water level

Claims (2)

[Claims] Claim 1: A measurement pipe buried underground, an insertion cart inserted into the measurement pipe over a predetermined measurement section, a reference water tank for setting a reference water level for measurement, and a reference water tank connected to the reference water tank. , a communication pipe laid on the insertion trolley, a sinkage meter attached to the insertion trolley at predetermined measurement intervals and connected to the communication tube, and a recording device to which an output cable of the sinkagemeter is connected. An underground subsidence measurement device consisting of. 2. The underground subsidence measuring device according to claim 1, further comprising an alarm that outputs an alarm when the detected value of the subsidence meter exceeds a predetermined subsidence limit value.