JPH07300845A - Preventive method against liquefaction of underground linear structure - Google Patents

Abstract

PURPOSE:To narrow the soil improvement range and compact the soil in a specified strength, in the measures against liquefaction of a continuous urnderground linear structure linearly crossing on the ground of a road, a railroad, or an embedded material, or in the ground. CONSTITUTION:Earth is retained by ready-made steel pipe piles 3 and excavated to the depth of the bottom plate of an underground linear structure. After that, a drain material 5 is laid down at the backside of the steel pipe pile 3. And a soil 6 coping with fluidization is filled back between the structure and the steel pipe pile.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a liquid of a continuous underground linear structure that crosses linearly on or under the ground such as underground buried objects such as roads, railroads, common ditches and excavated roads. It is related to the anti-chemical construction method.

[0002]

2. Description of the Related Art Conventionally, as a construction method of this kind, (a) by installing steel sheet piles or steel pipe piles having a drainage function in the longitudinal direction of a structure, the excess pore water pressure generated in the ground during an earthquake can be eliminated. A method to prevent the ascent and to disperse it to hold the ground and the structure stably. (B) Sand ground surrounded by the solidified ground by solidifying and improving the liquefied ground in the longitudinal direction of the target structure. The method of suppressing the shear deformation and preventing the generation of excess pore water pressure is adopted.

[0003]

However, a steel sheet pile or a steel pipe pile having a drainage function as described in (a) above requires a larger penetration force into the ground than existing steel sheet piles or steel pipe piles, The ground deformation due to the intrusion also becomes large. In addition, to prevent shear deformation in the sand ground at the time of an earthquake as in (b) above and to prevent the occurrence of excess pore water pressure,
In the case of performing only the ground improvement by solidification treatment, it is necessary to improve to a wide range and a deep depth (non-liquefied layer).

Further, it is difficult to solidify the narrow space between the steel sheet pile and the structure to obtain the required strength and compaction. The present invention has been proposed in view of the above problems of the prior art, and the purpose thereof is to use an off-the-shelf steel pipe sheet pile, which makes it possible to narrow the range of ground improvement. The point is to provide a liquefaction countermeasure construction method.

[0005]

[Means for Solving the Problems] In order to achieve the above-mentioned object, according to the method for liquefaction countermeasures for underground line-shaped structures according to the present invention, a steel pipe sheet pile is used for mountain retaining to excavate the structure bottom plate. After that, a drain material is installed on the back surface of the steel pipe sheet pile to narrow the ground improvement range, and the fluidized soil is backfilled between the structure and the steel pipe sheet pile to compact the narrow range with a predetermined strength. It is a thing.

[0006]

According to the present invention, as described above, the off-cutting of steel pipe sheet piles is used to excavate the structure and the bottom slab of the structure is excavated. Compared with a functional steel sheet pile, the ground deformation due to the penetration force into the ground and the penetration of the sheet pile into the ground is reduced.

After the excavation, by installing a drain material on the back surface of the steel pipe sheet pile, the drainage function and solidification of the drain material suppress the rise of pore water in the ground at the bottom of the structure and narrow the range for ground improvement. Further, by filling back the fluidized soil between the structure and the steel sheet pile in parallel with the installation of the drain material, it becomes possible to compact the ground in a narrow range with a predetermined strength.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments shown in the drawings in which the present invention is applied as a countermeasure against the liquefaction of underground wire-like structures used as common grooves will be described below. Ground 2 where underground linear structure 1 is constructed
Then, a ready-made steel pipe sheet pile 3 is penetrated along the longitudinal direction of the structure 1 until it reaches the impermeable layer 4, a mountain retaining wall is constructed, and excavation is performed to the bottom plate position of the structure 1.

Next, a hole for installing the drain material 5 is formed on the back surface of the steel pipe sheet pile 3 only at a place where the drain material 5 is provided to a position deeper than the excavation bottom, and an artificial drain material made of plastic or the like is provided in the hole. Drain material 5 consisting of
It is installed on the back surface of the steel pipe sheet pile 3 up to the position for backfilling.
In parallel with the installation of the drain material 5, for example, backfilling between the steel pipe sheet pile 3 and the structure 1 with fluidized soil 6 in which soil, cement, and water are kneaded is performed to backfill the above work. Repeat until the final position, and compact the ground in a narrow area to the specified strength.

[0010]

EFFECTS OF THE INVENTION According to the present invention, the conventional steel pipe sheet pile without using a steel pipe sheet pile having a drainage function is used for mountain clasping, so that the penetration force into the ground and the penetration of the steel pipe sheet pile can be achieved. It is possible to suppress the deformation of the ground caused by the increase of the ground pressure and suppress the increase of the excess pore water pressure.

Further, according to the present invention, the drainage function of the drain material installed on the back surface of the steel pipe sheet pile and the soil improvement by solidification are used together to narrow the range of the ground improvement, and further, the steel pipe sheet pile and By filling the space between the structures with fluidized soil, it is possible to improve the ground in a narrow area, improve the workability, and improve the liquefaction countermeasure effect of the underground linear structure.

[Brief description of drawings]

FIG. 1 is a side sectional view showing an embodiment when the present invention is applied to a liquefaction countermeasure construction method for an underground wire structure used as a common groove.

FIG. 2 is a plan sectional view of FIG.

[Explanation of symbols]

 1 Underground linear structure 2 Ground 3 Steel pipe sheet pile 4 Impermeable layer 5 Drain material 6 Fluidized soil

Claims (1)

[Claims] 1. A precast steel pipe sheet pile is used for mountain clasping, and after excavating to a structure bottom slab, a drain material is installed on the back surface of the steel pipe sheet pile to narrow the ground improvement range, and the structure and the steel pipe sheet pile are combined. A liquefaction countermeasure method for underground linear structures characterized by filling back fluidized soil in between and compacting a narrow area to a specified strength.