JPS6254924B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for measuring the amount of ground subsidence.

BACKGROUND ART Conventionally, methods using a continuous subsidence meter, a method using a T-shaped subsidence meter, etc. are known to measure the amount of ground subsidence.

Among the known methods, one that allows multi-point measurement for each layer is a method in which a sinking element is fixed to the hole wall using a spring. This method has a problem in that it is difficult to securely fix the sinking element to the borehole wall.

In addition, since conventional subsidence meter sondes rotate freely in the borehole, the positional relationship between the subsidence sensor and subsidence meter sonde is not constant, and the position at which the subsidence meter sonde detects the subsidence element is uncertain, causing measurement errors. It had become one of the

The present invention has been made in view of the above-mentioned problems, and is capable of multi-point measurement of the amount of ground subsidence by layer, easy to install a subsidence element, and even with a guide groove.
The purpose of the present invention is to provide a measurement method that can regulate the rotation of a subsidence meter sonde and measure ground subsidence with high accuracy, and a device for implementing this method.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below based on the drawings.

The method for measuring the amount of ground subsidence according to the present invention involves drilling a hole 2 of a predetermined depth in the ground 1 where the amount of subsidence is to be measured, and filling the hole 2 with a material similar to that of the ground 1, such as bentonite cement. After filling the filler 3, a bottomed cylindrical extensible measurement tube 5 with a sinking element 4 such as a metal ring fixedly interposed therein is inserted and installed at each predetermined measurement position in the length direction, and this measurement tube A subsidence meter sonde 6 is inserted into the measuring tube 5, and while the subsidence meter sonde 6 is moved up and down along the measuring tube 5, the position of the subsidence element 4 fixedly interposed at a predetermined measurement position is sequentially detected, and its depth is measured. By measuring with a measurement tape 7 that is integrally attached to the subsidence meter sonde 6, the amount of displacement of each subsidence element 4 is detected as the amount of ground subsidence in a predetermined stratum.

The measurement tube 5 includes an outer telescopic tube 8 and an inner tube 9 with a guide groove.
It is formed into a double tube consisting of a double tube and is integrally attached at the lower end. Note that lubricant is injected between the inner peripheral surface of the outer telescopic pipe 8 and the outer peripheral surface of the inner pipe 9, so that the inner pipe that occurs when the outer telescopic pipe 8 expands and contracts in accordance with the sinking or rising of the ground 1. This is intended to reduce the frictional force with 9.

Further, the subsidence gauge sonde 6 has a pulley portion 10 that guides the descending movement inside the inner pipe 9 along the guide groove.
and a sensor section 11 that detects the sinking element 4 attached to a predetermined position on the outer circumference of the outer telescopic tube 8, and the sensor section 11 includes, for example, an oscillation section, primary and secondary coils, a detection amplification section, etc. Subsidence element 4
This is to detect the position of. That is, since the sensor section 11 is configured as shown in the block diagram shown in FIG. 3, when the coil section passes through the sinking element 4, a difference occurs in the electromagnetic induction voltage of the secondary coil, and after this signal is detected, The signal is amplified and transmitted to the display meter 12 on the ground, and the position of the sinking element 4 is detected.

As described above, the present invention involves filling a hole of a predetermined depth in the ground where the amount of subsidence is to be measured with a filler having similar properties to the ground, and then applying the filler to a predetermined measuring position in the longitudinal direction. Insert and install a measuring tube formed into a bottomed cylindrical tube with several sinking elements fixedly interposed therein, and formed into a double tube consisting of an outer expandable tube and an inner tube with a guide groove.
The pulley part is inserted from the ground along the guide groove in the inner pipe, and while the rotation in the hole is restricted and the subsidence meter sonde is moved downward, the positions of the subsidence elements affixed to predetermined measurement positions are sequentially detected, By measuring the depth with a measuring tape, the amount of displacement of each subsidence element is detected as the amount of ground subsidence in a predetermined stratum. The outer telescopic pipe expands and contracts by sensitively following the subsidence or uplift of the ground through the filler, and accurately transmits the amount of ground displacement to each subsidence element attached to the outer circumference of the outer telescopic pipe. This makes it possible to improve measurement accuracy, and by setting the number of subsidence elements and their attachment positions in various ways, multi-point measurement for each layer becomes possible.

Furthermore, since the pulley section moves up and down along the guide groove of the inner tube, the rotation of the subsidence gauge sonde in the horizontal plane is restricted, and the positional relationship between the subsidence element and the subsidence gauge sonde in the hole is always constant. Because it is held in
The reproducibility of detected subsidence positions has improved, making it possible to measure with high accuracy.

In the present invention, since only the measurement tube and the sinking element are buried in the soil, stable measurement over a long period of time is possible.

As described above, according to the present invention, it is possible to measure the amount of settlement of a reclaimed land, monitor uneven settlement, and by installing it horizontally, it is possible to measure not only the amount of settlement but also the amount of ground displacement in an extremely wide range, such as the amount of horizontal compression of the ground. This invention has tremendous effects on the measurement of

[Brief explanation of the drawing]

FIG. 1 is a schematic explanatory diagram of the present invention, FIG. 2 is a sectional view taken in the direction of the arrows in FIG. 1, and FIG. 3 is a block diagram of a sensor section of a subsidence meter sonde according to the present invention. 1 is the ground, 2 is the hole, 3 is the filler, 4 is the subsidence element, 5 is the measurement tube, 6 is the subsidence meter sonde, and 7 is the measurement tape.

Claims (1)

[Scope of Claims] 1. A bottomed hole in which a hole dug in the ground is filled with a filler having properties similar to those of the ground, and an appropriate number of sinking elements are fixedly interposed at predetermined positions in the length direction within the filler. A cylindrical extensible measuring tube is inserted and installed, and the position of each settling element is detected by a sinking meter sonde suspended from the ground within the measuring tube, and the depth of each is measured with a measuring tape. A method for measuring the amount of ground subsidence, characterized by measuring the amount of displacement of a subsidence element as the amount of ground subsidence in a predetermined stratum. 2. A hole drilled in the ground is filled with a filler having properties similar to those of the ground, and an appropriate number of sinking elements are fixed and interposed at predetermined positions in the lengthwise direction of the filler. A measurement tube is inserted and installed, and the position of each of the above-mentioned subsidence elements is detected by a subsidence meter sonde suspended from the ground into the measurement pipe, and the displacement of each subsidence element is determined by measuring the depth of each with a measuring tape. It is a device for measuring the amount of ground subsidence in a predetermined stratum, and includes a measuring pipe formed of a double pipe consisting of an outer expandable pipe and an inner pipe with a guide groove and integrally attached at the lower end thereof; A filler is filled between holes dug in the ground, a sinking element is fixedly interposed on the outer periphery of the outer expandable tube of the measurement tube, and a guide groove of the inner tube is formed inside the inner tube of the measurement tube. It is characterized by comprising a subsidence meter sonde which has a pulley part that moves up and down along the subsidence meter and is capable of detecting the position of each of the subsidence elements, and a tape for measuring the position detected by the subsidence meter sonde. Equipment for measuring the amount of ground subsidence.