JP2000241307A - Centrifugal model banking device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a centrifugal model banking device that can take account of change in bank with time for carrying out an experiment, based on an actual execution process when performing a centrifugal model experiment. SOLUTION: Sediment stock 10 that store sediment for banking are provided, the plurality of sediment stocks 10 are laminated at upper and lower parts as multiple-stage sediment stocks 10A, 10B, and 10C, a sediment supply port 14 that supplies the sediment to a bank model accommodation part 13 is provided at each of the sediment stocks 10A, 10B, and 10C, and a movable slit 16 that can block and open the sediment supply port 14 is provided at each of the sediment stocks 10A, 10B, and 10C. The movable slit 16 is moved during a centrifugal experiment for successively opening the sediment supply port 14, and the sediment is supplied to the bank model accommodation part 13 from each of the sediment stocks 10A, 10B, and 10C for banking.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a centrifugal model embankment producing apparatus suitable for conducting a model experiment using a centrifugal model experimental apparatus with respect to the behavior of soft ground or the like.

[0002]

2. Description of the Related Art It is generally known that the mechanical properties of the ground greatly differ depending on the so-called earth covering pressure. Therefore, in laboratory experiments, tests on mechanical properties are performed in various conditions by changing the confining pressure, but in model tests that capture the deformation behavior and fracture behavior of soil structures, the confining pressure is determined by the height of the model ground. It is expected that the overburden pressure will be determined, the size will be smaller than the full-scale model, and the deformation behavior will be different from the actual case.

[0003] Therefore, when examining the deformation and fracture behavior of soft ground, especially in a model test for a ground greatly affected by a stress field, a centrifuge model test using a centrifuge model test apparatus has been widely used in recent years. . The centrifugal model experiment has an advantage that the distribution state of the overburden pressure suitable for a full-scale can be reproduced by applying a centrifugal force even on a small model ground.

The centrifugal model experiment uses a centrifugal model experimental device such as a large centrifugal separator, and has a turning radius of 1 m.
The centrifugal force is generated by placing the model ground on this device and rotating it. During rotation, if necessary, photographs of markers installed in the ground, changes in stress state etc. are measured as data using measuring instruments such as displacement gauges, stress gauges, gap precipitation pressure gauges,
The obtained data is used for verification of the design method, verification of the ground improvement method, and the like.

[0005] In particular, in soft ground, the effect of the construction time on the deformation behavior characteristics is large, and simulation of the embankment process is very important even in model tests. Conventionally, when preparing an embankment for a centrifugal model experiment, a method of producing an embankment model in a 1G field (stationary state), or using a sediment hopper installed on the model ground surface in a centrifugal force field by centrifugal acceleration. There is a method of producing embankment at once by supplying earth and sand at one time.

[0006]

However, the production of the embankment in the 1G field is easy to produce a high-precision embankment model, but requires labor for experiments. Also, in consideration of the actual construction process, the embankment is not always prepared from the beginning, but it is a reality that the embankment is sequentially raised with time.

[0007] In addition, since a change in the height of the embankment over time greatly affects the deformation behavior of the soft ground, the method of producing the embankment at one time using a normal earth and sand hopper does not allow the time variation of the embankment to change. Simulation will not be possible.

[0008] The present invention has been made in view of such problems of the prior art.
It is an object of the present invention to provide a centrifugal model embankment manufacturing apparatus capable of conducting an experiment in consideration of a temporal change of embankment in accordance with an actual construction process.

[0009]

The present invention employs the following configuration in order to solve the above problems.

(1) A centrifugal model embankment production apparatus for supplying earth and sand to an embankment model storage section mounted on a platform swingably installed at one end of a rotating arm of a centrifugal model experimental apparatus, for embankment production The earth and sand stock part in which the earth and sand is stored is provided, and the earth and sand stock part is stacked up and down to form a multi-stage type, and the earth and sand supply port for supplying earth and sand to the embankment model storage part is provided in each of the earth and sand stock parts. A closing member capable of closing and opening the earth and sand supply port is installed in each of the earth and sand stock sections, and the earth and sand supply port is sequentially opened by the closing member during the centrifugal experiment, and the earth and sand stock section is stored in the embankment model storage section. The embankment is manufactured by sequentially supplying earth and sand from the river.

(2) In the above item (1), the closing member is a movable slit having a supply hole formed at an equal interval with the earth and sand supply port, and the movable slit is moved by moving the movable slit. A means is provided, and the movable slit is moved by remotely operating the slit moving means during a centrifugal experiment to open the earth and sand supply port.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is a front view schematically showing a centrifugal model embankment producing apparatus according to one embodiment of the present invention. As shown in the figure, the centrifugal model embankment production apparatus of the present embodiment is provided with a slit moving means 12, an embankment model storage unit 13 and the like, centering on a soil and sand stock unit 10. The earth and sand stock part 10 is divided into three layers vertically.
A, 10B, and 10C are stacked and arranged in a multistage manner, and a predetermined amount of earth and sand for embankment production is stocked in each of the earth and sand stock units 10A to 10C. A partition member 15 is provided in each of the earth and sand stock sections 10A to 10C in the vertical direction, and finely partitions the inside of each of the earth and sand stock sections 10A to 10C.

A sediment supply port 14 is formed below each of the sediment stock parts 10A to 10C, and the sediment stored in the sediment stock parts 10A to 10C falls downward from the sediment supply port 14. . Above the earth and sand supply port 14, a movable slit 16 is disposed as a closing member, and the movable slit 16 can be slid in the horizontal direction by the slit moving means 12. Movable slit 1
6, a plurality of supply holes 18 are formed at regular intervals with the above-mentioned earth and sand supply port 14, and the movable slit 16 stops at a position where the supply hole 18 coincides with the earth and sand supply port 14,
The earth and sand in the earth and sand stock sections 10A to 10C is the earth and sand supply port 1
4 and the supply hole 18, and is dropped into the embankment model storage unit 13 and supplied.

The slit moving means 12 includes a movable slit 1
6 and a driving unit 20 which also has a supporting function, and the driving unit 20 supports the movable slit 16 movably in the horizontal direction. The slit moving means 12 is connected to the slit control means 22 and controls the movement of the movable slit 16 with respect to the slit moving means 12. The slit control means 22 is capable of being remotely operated, and has a
Any of the movable slits 16 of A to 10C can be slid and moved. A model ground is formed in the box-shaped embankment model storage unit 13, and is mounted on a centrifugal model test device described later to perform a centrifugal experiment.

FIG. 2 is a front view of a centrifugal model experiment apparatus for performing a centrifugal experiment using the above-described centrifugal model embankment production apparatus. The centrifugal model experimental device is configured to include a vertical rotating shaft 24, a rotating arm 26, platforms 28A and 28B, a driving motor 30, and the like. Rotating shaft 24
Is capable of changing the rotation speed by a driving motor 30 to apply a desired gravity (G) to platforms 28A and 28B swingably attached to the end of the rotating arm 26. Is available. On one platform 28A, the aforementioned FIG.
The embankment model storage unit 13 indicated by is indicated. On the other platform 28B, a counterweight 32 is mounted to maintain balance during rotation.

Next, the operation when the behavior of the ground is examined by a centrifugal experiment using the centrifugal embankment manufacturing apparatus configured as described above will be described.

The model ground is placed in the embankment model storage section 13. The form of the model ground is, for example, embankment work, excavation work, underground structure (culvert, earth retaining) formed on soft ground. Such as civil engineering work in general. Here, an embankment experiment will be described as an example.

First, the embankment model storage unit 13 (width 20 cm to
Clay ground (height 1) simulating soft ground within 200cm)
0 cm to 50 cm), and an embankment model using sandy soil is prepared thereon. Further, as shown in FIG. 2, the embankment model storage unit 13 in which the embankment model has been manufactured is mounted and fixed on a platform 28A. Further, a predetermined amount of earth and sand corresponding to the final embankment shape is put into each of the earth and sand stock sections 10A, 10B, and 10C.

FIG. 3 is a front view showing a state in which the centrifuge model test apparatus is operated. In the drawing, the platforms 28A and 28B swing upward as indicated by arrows due to the centrifugal force generated by the rotation of the rotating shaft 24, and a predetermined gravity (G) is generated in the embankment model. For example, if the centrifugal acceleration is 50 G and the model ground depth is 20 cm, 20 c
It corresponds to the behavior reproduction of the actual ground of m × 50 = 10 m.

During the rotation of the centrifugal model experiment apparatus, the slit moving means 12 of the embankment producing apparatus is controlled
Is operated to slide the movable slit 16 in order from the bottom. First, the earth and sand charged in the earth and sand stock part 10C is supplied to the embankment model storage part 13 to form the embankment. Next, the movable slit 16 is opened in the order of the earth and sand stock units 10B and 10A, and the stored earth and sand is supplied to the embankment model storage unit 13. During the supply of sediment, photographs of markers installed in the ground are taken as necessary, and changes in stress state and the like are measured using measuring instruments such as displacement gauges, stress gauges, and pore precipitation pressure gauges. The measured data is used for verification of design method, grasp of failure mode and study of design method, verification of ground improvement method, etc.

As described above, according to the present embodiment, the earth and sand stock unit 10 storing the earth and sand is of a multi-stage type, and the embankment is produced gradually in accordance with the actual construction procedure. Therefore, it is possible to perform an experiment while modeling the actual construction process in a centrifugal force field, and it is possible to simulate a temporal change in the embankment construction process, thereby enabling a highly accurate experiment.

In addition, since the embankment can be produced during the rotation, it is not necessary to temporarily stop the rotation of the centrifugal model test apparatus when producing the embankment, which was conventionally required, so that the embankment is not affected by the stress release. Experiments to simulate ground behavior are possible.

In this embodiment, the movable slit 16 is used as a closing member for closing and opening the earth and sand supply port 14. However, the present invention is not limited to this, as long as the earth and sand supply port 14 can be closed and opened. Any member may be used.

[0025]

As described in detail above, according to the centrifugal model embankment manufacturing apparatus of the present invention, when conducting a centrifugal model experiment, the temporal change of the embankment process is also taken into account in accordance with the actual construction process. Experiment can be performed.

[Brief description of the drawings]

FIG. 1 is a front view schematically showing a centrifugal model embankment manufacturing apparatus according to an embodiment of the present invention.

FIG. 2 is a front view of a centrifugal model experiment apparatus for performing a centrifugal experiment using the centrifugal model embankment production apparatus of FIG. 1;

FIG. 3 is a front view showing a state in which the centrifuge model test apparatus of FIG. 2 is operated.

DESCRIPTION OF SYMBOLS 10 earth and sand stock part 10A 10B 10C earth and sand stock part 12 slit moving means 13 embankment model storage part 14 earth and sand supply port 15 partition material 16 movable slit 18 supply hole 20 drive part 22 slit control means 24 rotation axis 26 rotation arm 28A, 28B Platform 30 Driving motor 32 Counterweight

Claims (2)

[Claims] 1. A centrifugal model embankment production apparatus for supplying earth and sand to an embankment model storage section mounted on a platform swingably installed at one end of a rotating arm of a centrifugal model experimental apparatus, comprising: Establish a sediment stock section where sediment is stored,
This earth and sand stock part is stacked up and down to make a multi-stage type,
A sediment supply port for supplying sediment to the embankment model storage part is provided in each of the sediment stock parts, and a closing member capable of closing and opening these sediment supply ports is installed in each of the sediment stock parts. A centrifugal model embankment manufacturing apparatus, characterized in that the earth and sand supply port is sequentially opened by a closing member and earth and sand are sequentially supplied from each of the earth and sand stock sections to the embankment model storage section to produce an embankment. 2. The method according to claim 1, wherein the closing member is a movable slit having a supply hole formed at an equal interval with the earth and sand supply port, and a remotely movable slit moving means for moving the movable slit is provided. 2. The centrifugal model embankment production apparatus according to claim 1, wherein the movable slit is moved by remotely controlling the soil during the centrifugal experiment to open the earth and sand supply port. 3.