JP2003155736A - Method for discriminating support force of back filled soil and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problems in a conventional CBR device at site wherein a large-scale test must be conducted by several persons because measurement is performed by taking a reaction force in a machine body such as a truck, a measuring device has a complicated structure, much time and labor are required for assembly, and the device is expensive. SOLUTION: A bearing power discrimination device 1 provided with a penetration piston 2, an indicator 4 for indicating a penetration amount, and a loading part 6 for loading a weight having a fixed weight as loading load is used, loading load corresponding to a target CBR value or a cone value is calculated, and load is sequentially applied while observing an amount of settlement to discriminate where bearing power is satisfactory or not from the amount of settlement when all the calculated loading loads are applied.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for determining a bearing capacity of backfill soil for easily measuring a roadbed bearing force on site when digging soil is buried.

[0002]

2. Description of the Related Art A roadbed has a required roadbed support force according to the road specifications. . When excavating a trench in a road to lay, modify, repair, maintain, etc. a pipeline, etc., and bury the backfill soil to restore it, it is necessary to secure the prescribed subgrade support according to the specifications of the road. I have to. For this reason, it is necessary to determine at the site whether the excavated soil may be backfilled as it is or whether it is necessary to backfill it with another improved soil.

Conventionally, when measuring such a roadbed supporting force on site, the CBR value was measured using an on-site CBR device, and it was confirmed that the CBR value was a certain value or more.
For example, the road occupation construction summary of Tokyo (Notification No. 4 of 1979)
No. 26) stipulates that the standard value of the improved soil or the improved soil used for backfilling should be 3% or more in the case of restoration of excavation traces due to private use. CBR (California)
The Bearing Ratio) value is the bearing capacity index of the subgrade soil for determining the suitability of the subgrade material. Usually diameter 5c
The penetration piston of m is penetrated to a specified depth, the required load at that time is obtained as a ratio to the standard load at that depth, and this is expressed in percentage, and is represented by the following formula.

CBR value = {(load) / (standard load)} ×
100 (%) When measuring this CBR value in the field, a field CBR device is used. In the conventional field CBR device, a penetration piston is placed on the ground to be measured, and the upper end of the device is brought into contact with a part of heavy equipment such as a truck or power shovel to support the reaction force of the penetration piston, and the penetration is performed by hydraulic pressure or a manual handle. Push the piston into the ground, measure the applied load and the amount of penetration into the ground,
Record this on a chart and use this chart to
It is designed to judge the value.

[0005]

The on-site CBR device uses a machine body such as a truck or a heavy machine as a reaction force device of a penetrating piston, and arranges the on-site CBR device so as to receive a reaction force by these and performs measurement. Therefore, it was a large-scale test in which several people cooperated. In addition, since the loading method of the measuring apparatus is not simple, the measuring apparatus has a complicated structure, and it takes a lot of time to assemble it, resulting in an expensive apparatus. The present invention solves such a problem and develops a measurement technique using a simple method and device,
It is intended to provide this.

[0006]

The present invention has been made to solve the above problems, and calculates a loading load corresponding to a target CBR value or a target cone value, and makes the calculated loading load plural. Divide and sequentially apply the divided loading load to the penetrating piston while observing the subsidence amount, obtain the subsidence amount of the penetrating piston after loading the above-mentioned load load, and judge whether the supporting force is acceptable or not from the subsidence amount. Is a method for determining bearing capacity of backfilled soil. The CBR value is originally a measuring method based on the basic idea of a displacement control method.
This is a method in which a load is applied so as to settle in mm, the movement of the upper end is set to 0 by a reaction force device, and the load speed is controlled while performing measurement. Therefore, it is necessary to support the reaction force of the penetrating device by the reaction force supporting device, and the load is measured while controlling the displacement, and many measurements are plotted to determine the result. For this reason, an expensive device, a troublesome reaction force device, and a lot of manpower are required. The present inventors have developed the above-mentioned novel method of determining whether or not there is a necessary supporting force with a simple device and effort.

The apparatus of the present invention capable of suitably carrying out the above method is a penetration piston for measuring the subgrade supporting force of backfill soil, an indicator for instructing the penetration amount, and a constant amount of a crushing load as a loading load. A bearing capacity determination device for backfilling soil, comprising: a loading unit for loading a soil.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 shows a conventional field CBR device 10
FIG. The on-site CBR device 10 causes a heavy machine 20 such as a truck or a power shovel to support a reaction force of a penetration force of a penetration piston into the ground through a reaction force support member 14 or the like. Then, a load is applied to the on-site CBR device 10 by a manual or hydraulic load device 11, and the amount of sinking into the ground 21 is measured by the penetration amount indicating device 12. At this time, the load is applied by the displacement control method. For example subsidence per minute performs a load controlled to 1 mm, and record the measurement changes, these data load as shown in FIG. 3 - is displayed in subsidence curve 30, the predetermined subsidence alpha ₁ Then, the load P ₁ is calculated. The load P ₁ is compared with the reference load to obtain the CBR value as the roadbed supporting force as described above. Such conventional CBR value measurement requires the use of heavy equipment such as trucks and shovels as a reaction force device, and is a large-scale test performed by several people. The measurement device also has a complicated structure and is troublesome to assemble. Takes a
It was an expensive device.

FIG. 1 is a supporting force determining device 1 according to an embodiment of the present invention.
It is a perspective view explaining. This device 1 is provided with a loading portion 6 on the top of a penetrating piston 2 having a weight 3 attached thereto, and a loading load 7 is placed thereon. Dial gauge 4
Indicates the sinking amount of the penetrating piston 2. The load supporting portion 8 is a cylindrical member that supports the load 7 and is preferably made of acrylic resin or the like so that the condition of the load 7 can be visually checked. As the loading load 7, a load corresponding to the target CBR value or the target cone value is calculated in advance, and the load is divided into a plurality of parts so as to be loaded. Since the body of the supporting force determination device 1 is made of lightweight and sturdy material such as reinforced aluminum and reinforced plastic, it is convenient to carry and very convenient. Place multiple weights on the penetrating piston 2 one after another,
The amount of penetration of the penetration piston 2 into the ground and the loading load at that time are measured. The device of the embodiment is a device for simply measuring the bearing force of the roadbed that has been compacted when backfilling the excavation pit construction, and does not require a reaction force device such as a heavy machine and can be carried and installed and measured by one person. You can The procedure for measuring the supporting force using the device of the present invention is as follows. (1) Calculate the loading load corresponding to the target CBR value or the target cone value. (2) Divide the calculated load into a plurality. (3) While observing the subsidence amount, the divided loading loads are sequentially applied to the penetrating piston. (4) Obtain the subsidence amount of the penetrating piston after all the applied load is applied. (5) From the amount of subsidence, it is judged whether the supporting force is acceptable or not.

For example, in the apparatus of the embodiment, the load corresponding to the CBR value of 3% is 41.1 kg, and if the sinking amount at that time is 2.5 mm or less, the CBR value becomes 3% or more. C
The correspondence with the BR value has been confirmed with 100% accuracy as a result of comparing many actual test values. Therefore, the device of the present invention can make highly reliable determination by simple measurement.

Further, in the apparatus of the present invention, the load for the target CBR value or the target cone value is not calculated in advance, but the load is applied to the penetrating piston and the penetrating amount that the penetrating piston penetrates into the compacted soil. Can also be measured and converted from the measured value into the corresponding CBR value and cone index. Then, it is possible to determine whether or not it can be used as a backfill material based on the obtained CBR value. The loading method using the embodiment apparatus is a simple loading method in which a plurality of weights are placed on the penetrating piston. Moreover, since the device has a compact shape, it is easy to carry and measure.

[0012]

According to the present invention, the CBR value or cone index of backfill soil can be easily and quickly determined, and whether or not the test material can be used as the backfill material can be quickly and accurately determined. For example, the civil engineering construction management standard in Tokyo defines a CBR value of 3% or more and a cone index of 8 or more, and a load corresponding to this can be calculated and easily measured.

Since the loading method is different from that of the conventional apparatus, the apparatus is simple, and since it has no complicated structure, it is easy to manufacture and inexpensive. Conventionally, a reaction force was taken by a truck or a hydraulic jack was used for loading, but in this case, a simple operation of placing a plurality of weights on the penetrating piston is sufficient.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a supporting force measuring device according to an embodiment.

FIG. 2 is a diagram illustrating the use of a conventional field CBR device.

FIG. 3 is a graph showing a load-squat amount curve.

[Explanation of symbols]

1 Supporting force determination device 2 Penetration piston 3 weights 4 dial gauge 5 boxes 6 loading section 7 Loading load 8 load support 10 On-site CBR equipment 11 load device 12 Penetration amount instruction device 13 Subsidence 14 Reaction force support member 20 heavy machinery (reaction device) 21 Ground 30 load-sink curve

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Daisuke Ujiie             1-5-20 Kaigan, Minato-ku, Tokyo Tokyo Gas             Within the corporation F-term (reference) 2D043 AA01 AB03 BA10                 2G061 AA02 AB01 BA06 CA06 EA01                       EA02

Claims (2)

[Claims] 1. A loading load corresponding to a target CBR value or a target cone value is calculated, the calculated loading load is divided into a plurality, and the divided loading load is sequentially applied to the penetrating piston while observing the sinking amount. A method for determining the bearing capacity of backfill soil, comprising: determining a sinking amount of the penetrating piston after applying the above-described load, and determining whether the bearing force is acceptable based on the sinking amount. 2. A penetrating piston for measuring the subgrade supporting force of backfill soil, an indicator for instructing the amount of penetrating, and a loading section for loading a fixed amount of crushing as a loading load. A device for determining the bearing capacity of backfill soil.