JPH072796Y2 - Mold gauge for stress measurement of support work - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention integrates a plurality of strain gauges necessary for calculating the stress state of the ground bearing steel support of underground cavities such as tunnels. The present invention relates to a stress measurement mold gauge.

[Conventional technology]

Rock bolts, steel supports, and the like are used as hollow support materials when excavating a tunnel.

In general, it is very difficult to accurately predict conditions such as initial rock stress, deformability, cracks, and spring water in advance in rocks or rocks where underground cavities such as tunnels are excavated. Therefore, in order to know whether these supporting materials are exerting the supporting effect as designed, or how much stress is actually occurring in the supporting material and how safe it is against damage. Often, the stress state is often calculated by directly adhering a strain gauge to these steel materials.

When trying to accurately grasp the stress state of steel support,
Generally, a measuring method called “Murayama method” is used. This is from the strain measurement of the support work used in the field,
The major feature is that the magnitude and direction of the stress acting on the support work can be calculated.

[Problems to be solved by the device]

However, with this method, there are three
The strain gauges are bonded in the arrangement shown in the figure. That is, it is necessary to bond one biaxial orthogonal strain gauge [b], two uniaxial strain gauge [c] and four dummy gauges [d] to the support web [a], a total of seven gauges. There is.

Now, if it is attempted to provide such measuring points at five points on one side of the supporting work, it is necessary to perform bonding 70 times in total on both sides including bonding of the dummy gauge. Therefore, a total of 140 adhesions must be done manually by one steel support. In order to set the above-mentioned biaxial orthogonal strain gauge [b] and uniaxial strain gauge [c] that are directly bonded to this inner steel support, it is necessary to mark the positions and then bond them accurately. The work is very complicated and the most labor intensive. Especially, in the case of a small steel support, there is a problem that the work becomes more difficult.

[Means for Solving the Problems]

In view of such circumstances, the present invention proposes that a plurality of strain gauges excluding the dummy gauge are accurately arranged in advance and are molded with a soft plastic to be integrated according to the dimensions of the steel support to be targeted. By using the means, the above-mentioned problems of the prior art are largely solved.

[Action]

According to the mold gauge of the present invention, at least the above-mentioned three strain gauges are integrally molded in a state where they are accurately arranged in accordance with the standard of support work, so that there is no variation in gauge position and reliable measurement accuracy can be obtained. In addition to having a special effect, it also has the effect of making the work of adhering the gauge efficient.

[Embodiment] The construction of the support gauge stress measuring mold gauge according to the present invention will be described in more detail below with reference to an embodiment. In FIG. 1, 1 is a uniaxial strain gauge, and 2 is a biaxial orthogonal strain gauge. They are properly arranged in advance in accordance with the dimensional standards of steel supporters, and 3 is a conductor wire of each of the gauges, and 4 is a flexible poxy resin in which the gauges 1 and 2 are integrally molded.

Then, as shown in FIG. 2, the mold gauge having the above-mentioned structure is bonded to each of the measuring points of the steel supporting bar 5 one by one.
Two dummy gauges 6 are attached to a predetermined position and each gauge is adhered to each measurement point in the same manner.

[Effect of device]

According to the mold gauge for supporting work stress measurement of the present invention having the above-mentioned configuration, it is possible to simplify the marking work of the gauge sticking position of the steel supporting work, which has been conventionally performed in the field, and it is possible to significantly reduce the labor of the site work. In addition to the effect of, the multiple strain gauges that have been placed in precise positions in advance are integrated as they are, so compared to the conventional method of individually bonding the strain gauges It is possible to expect a remarkable effect that the adverse effect of can be removed and the measurement accuracy can be surely improved.

[Brief description of drawings]

FIG. 1 is a plan view of the mold gauge of the present invention, and FIG. 2 is a cross-sectional view of the mold gauge bonded to one measuring point of a steel support, and FIG. 3 is a conventional steel gauge. The front view of the gauge adhered to each of the measurement points of the support work is shown. In the figure, 1 ... 1-axis strain gauge, 2 ... 2-axis orthogonal strain gauge, 3 ... Conductor wire, 4 ... Mold resin, 5 ... Steel support, 6
… Indicates a dummy gauge.

Claims (1)

[Scope of utility model registration request] 1. A biaxial orthogonal strain gauge and two uniaxial strain gauges are arranged in advance at precise positions according to the dimensions of the steel support, and the three strain gauges are softened in that state. Mold gauge for stress measurement of supporting work characterized by being molded into plastic and integrated.