JP2679235B2 - Soft ground reclamation method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a soft ground reclamation method, and more particularly to a geotextile post-tension method.

(Prior art) Conventionally, as a countermeasure against soft ground, a replacement method that replaces soil, a ground improvement method that hardens soft soil, a sand pile method that raises the bearing capacity of the ground and aims for drainage, old soda floor The construction method such as doing is known. In any case, when soft soil is filled with soil particles in the water and the embankment is placed on top of this, the shape of the embankment is not stable and soil particles on the soft soil contact each other to cause excess soil. It takes a considerable amount of time to settle down while eliminating water, and it is said that it will take 10 to 80 years until the final settlement. For this reason, the above soft ground countermeasures have been taken, and recently, sheet-like geotextiles have been laid and the soil layer is separated by the tensile force of the sheet, and the slippage of the upper embankment is prevented and the shape of the embankment is stabilized quickly. The method is taken.

(Problems to be solved by the invention) When a sheet-like geotextile as described above is laid, separation of the embankment and soft ground and slip failure of the embankment are prevented, but the soft ground is affected by the load applied on the geotextile by the embankment. Had a problem that the shape of the soil could not be determined forever as the soil subsided and the embankment continued to subside.

The present invention is to provide a method for laying a geotextile which can prevent or delay consolidation settlement of the soft ground when laying the geotextile as a countermeasure against the soft ground and can use the embankment quickly.

(Means for Solving the Problem) That is, the present invention is a method for laying a geotextile, which is a soft ground reclamation method characterized by converting and supporting the passive earth pressure of the embankment itself. The geotextile here is not only woven fabrics, knitted fabrics and braids made from fiber yarns, fiber tapes and slit films, but also non-woven fabrics such as spunbond method, needle punching method, resin processing method and melt blow method, as well as geo-processed resin. Any of nets or plastic grids molded with resin, or sheet-like materials used for civil engineering such as films or resin-coated geomembranes may be used. As described above, these are laid on the soft ground as a measure against the soft ground, and are used for the purpose of separating the upper layer by the tensile force of the sheet or preventing slip failure of the embankment.

The resistor is preferably a concrete plate, and may be a plastic plate or a metal plate, and the shape may not be plate-like but curved inward, but the embankment load is the passive earth pressure of the embankment itself. The size and strength that can convert and support the required strength and strength are those that can receive the required passive earth pressure against the calculated vertical load of the embankment, and the safety factor is 2
It should be doubled.

The method of fixing to the geotextile may be tied to the resistor with a rope or may be tightened with a bolt, but it is desirable to wind the sheet around the resistor for the purpose of construction. The method of fixing the resistor is, for example, in FIG. 1, placing the resistor 2 on both sides of the embankment 5 to which a vertical load is applied, winding the geotextile 3 around the resistor 2, submerging the resistor 2 in the soft ground, and softening the geotextile 3 in the soft ground. Lay it on the surface and put it on. After assuming that the resistor 2 has been attached, the resistor 2 is fixed, and the pre-embankment 4 is performed inside the resistor 2 so that the resistor does not move in the embankment in the subsequent step.

(Operation) According to the configuration of the present invention, when the load of the embankment 5 is applied to the geotextile 3, the vertical load is converted into the passive earth pressure of the embankment 5 itself by the resistor 2 fixed to the geotextile 3, and The load is not directly applied to the soft ground and is widely relaxed.

(Example) Example 1 N value was 2 for the ground bearing capacity of the soft ground to the extent that one person stands and sinks. A 4m high embankment on top of this, 6m on the top and 22m on the bottom
It was decided to construct a 6m wide road with a trapezoidal cross section.

On the other hand, a concrete plate having a height of 2 m, a length of 8 m and a thickness of 20 cm was prepared as a resistor. At the construction site, a depth of 1m to fill the resistor with 18m width on both sides of the planned road along the center line.
I made a moat and built a geotextile with a resistor wrapped with geotextile for 1 m, and put on a hypothetical resistor.

After this, pre-filling was performed inside the resistor up to a height of 50 cm above the resistor with an upper base width of 2 m and a slope of 1: 2.

As a result, after fixing the resistor, embankment with a height of 4m is performed and a width of 6m.
A road with a slope of 1: 2 was constructed.

After the construction, the subsidence of the road was measured over time, but in the embankment of the same class where normal geotextile was laid, it was 1 in the first year.
Although a subsidence of about 10 mm is seen annually, the construction method of the present invention subsided at about 3 mm in the first year of the first year.

(Effect of the invention) When embankment was loaded on soft ground, not only the original upper layer separation of geotextile and the prevention of slip fracture, but also consolidation settlement of soft ground was prevented, the embankment was stabilized quickly, and utilization of the upper part could be accelerated.

[Brief description of the drawings]

 FIG. 1 is a sectional view of a soft ground reclamation part. 1 ... Soft ground, 2 ... Resistor 3 ... Geotextile.

Claims (1)

(57) [Claims] 1. A method of laying geotextiles, which comprises converting a load of embankment into a passive earth pressure of the embankment itself by a resistor fixed in advance by geotextiles and supporting the soft ground reclamation method.