KR19990073866A - Natural hemp fiber vertical drainage and consolidation promotion method using the same - Google Patents

Abstract

The present invention relates to a vertical drainage method that is used for early settlement and strength enhancement of large-scale soft ground, and more particularly, to a consolidation promotion method using a vertical drainage material made of natural hemp fiber.

The natural hemp fiber drainage material used in the present invention is not inferior in performance in comparison with the conventional plastic drainage material (PD material), and is not significantly affected by long-term application or deformation and uses petrochemical materials. Unlike PD materials, natural materials are used, and after a predetermined period of time after drainage functions, they are decomposed by bacteria in the ground and finally have an environmentally friendly characteristic of assimilation with soil.

The present invention consists of a core made of natural palm fiber and a filter material of jute material surrounding the core, and is manufactured in various forms such as circular, eight-shaped, and plate-shaped according to the diameter of the core and the arrangement of the cores.

Description

Natural Jute fiber Drainage Material and Ground Improvement with a Vertical Drain System using the same

The present invention relates to a vertical drainage method that is used for the early settlement and strength enhancement of large-scale soft ground. More specifically, the present invention relates to a consolidation promoting method using a vertical drainage formed of natural hemp fibers.

Sand drain method has been used as a method for improving the ground by drainage to prevent premature settlement of large-scale soft ground and to increase strength. The sand drain method is a typical method of vertical drainage method, which promotes drainage effect by artificially placing sand piles in the ground using sand as a permeable material. However, the sand drain method is lacking in recent years. As a material to compensate for some of the problems, the plastic board draining method (Plastic Board Drain, PD material method) wrapped around the plastic core with fabric fibers has been widely used in Korea, and the results have been confirmed at many sites. However, even in the plastic drain method, a firm reliability for efficiency and applicability is not secured.

The reason for the lack of reliability is the problem of PD material itself. Firstly, the water-permeability of band-type PD material is greatly influenced by the side pressure in proportion to the thickness of the weak layer to be improved. Over time, it is difficult to apply for a long period of time because the small size of the granules smaller than the air gap of the filter passes through the filter material and accumulates in the drain material, or the larger size of the granules blocks the air gap of the filter. There is a problem.

In addition, as the ground is settled and deformed vertically, the performance of the drainage material is greatly reduced by bending or bending the drainage material.

There is a need for the development of a new type of drainage material that can overcome the performance limitations of drainage materials such as low water flow capacity, long-term applicability, and drainage function of PD materials. As a material, it can cause problems that pollute the ground environment. The present invention has been developed to overcome the limitations of such PD material.

An object of the present invention is to provide a drainage material for use in the consolidation promotion method of soft ground and a method for constructing the material using the material.

Another object of the present invention is a problem of lack of efficiency and reliability of the band-shaped plastic drain method (Plastic Board Drain Method, hereinafter referred to as 'PD material method') wrapped with a conventional plastic core with textile fibers. It is to provide a natural hemp fiber vertical drainage to solve and the consolidation promotion method using the same.

Still another object of the present invention is to provide an environmentally friendly drainage method that is decomposed by microorganisms and finally assimilated with soil after a certain period of time after fulfilling the function of drainage using natural materials.

1 is a view showing a natural hemp fiber vertical drainage having a circular cross section as an embodiment of the present invention.

2 is a view showing a natural hemp fiber vertical drainage having an eight-shaped cross section as another embodiment of the present invention.

3 is a view showing a natural hemp fiber vertical drainage having a plate-shaped cross section as another embodiment of the present invention.

4 is a view showing a method of construction as a natural hemp fiber vertical drainage material of the present invention.

<Description of Major Symbols in Drawing>

10; Natural hemp fiber drainage 11, 11 'of circular cross section; Round core

12; Two-ply filter material 13; suture

20; Natural hemp fiber drainage with 8-sided cross section

30; Natural hemp fiber drainage with plate cross section

41; Pouring equipment 42; Mandrel

43; Soft ground 44; Sand layer

45; Fill layer

The natural hemp fiber drainage material used in the present invention is not inferior in performance in comparison with the conventional PD material, and is excellent in its material characteristics such as not being greatly influenced by long-term application or deformation, such as an indoor test. It is confirmed through. In particular, one of the notable characteristics of this natural hemp fiber drainage is that unlike the PD material using petrochemical materials, it is decomposed by the bacteria in the ground after a certain period of time after the drainage function is completed by using natural materials. It is environmentally friendly to assimilate with soil.

The raw material of natural hemp fiber drainage is made of palm bark which is abundant in Southeast Asia, and its material cost is low, and the material itself has excellent engineering properties. The characteristics and advantages of this natural hemp fiber drainage method are as follows.

First, it is a material having a predetermined function as a drain. The water permeability, filtering effect, and tensile strength of the material can be used as a vertical drainage, and the uprightness is so strong that there is little cutting or bending when pouring. In particular, the tensile strength of natural hemp fiber drainage is about 500 kgf / material width or more (tension rate 500mm / min, JIS K6745), which is much higher than that of general PD materials (about 30-50kgf / material width). Have.

Second, the improvement of the surrounding ground can be made homogeneous. Unlike general PD materials, natural filter of natural hemp fiber drainage does not only block the inflow and outflow of fine-grained soil and pass the pore water, but the outer filter is easily mixed with the surrounding soil. Induces the discharge of pore water in one state. Therefore, since normal PD material is generated faster than pore water discharged from the ground near the drainage material, the adjacent land of PD material is improved faster and its density is increased, so that the homogeneous improvement is not achieved. There is an advantage that the improvements can be made in a balanced manner.

Third, it is a drain material using materials that are environmentally superior and assimilated with soil. The material is jute as a filter material and the core part is palm fiber. After its function as a drainage material, it is biodegraded by bacteria in the ground and assimilated and disappeared in the soil, so that existing petrochemical products remain in the ground even after a long time. The problem of pollution can be solved.

Fourth, less influence due to deformation. If settlement occurs in the target ground to be improved, the drainage material placed in the upright can be bent or bent due to the vertical deformation. However, the natural hemp fiber drainage does not significantly reduce the water-permeability even in the bent state. Even if the settlement in the vertical direction is deformed depending on the degree of deformation of the ground, the degree of bending is smaller than that of other PD materials.

Hereinafter, the present invention will be described in detail by embodiments of the present invention.

1, 2 and 3 show the cross-sectional shape and size of natural hemp fiber drainage as an embodiment of the invention.

1 is an elevation view and a cross-sectional view of a drain 10 having a circular cross section as a first embodiment. A thin natural palm fiber having a diameter of about 2 mm and having a circular core 11 twisted in a circular shape so as to have a diameter of about 20 to 24 mm, and having two layers of jute material filter material 12 on the circular core 11. After wrapping in a circular shape, one side of the filter material is sutured (13). The natural hemp fiber drainage of circular cross section is about 33-38 mm in diameter.

When the natural hemp fiber drainage is manufactured in a circular shape as shown in FIG. 1, the mandrel, which is a device that protects the drainage material and can be placed upright to a predetermined depth when placing the drainage material in the ground, is as it is. There is an advantage that can be used, since the diameter is smaller than 40mm, when the diameter of the mandrel is reduced, the influence of disturbance caused to the surrounding ground is reduced, thereby maximizing the drainage effect.

2 is an elevation view and a sectional view of a natural hemp fiber drainage 20 having an eight-shaped cross section as a second embodiment. The eight-shaped natural hemp fiber drainage is 20-24 mm in diameter and seals at least two drainages of circular cross section which are slightly smaller than the circular drainage of FIG. The diameter of the drain and the number of drains in the circular cross section can be adjusted according to the design.

3 is an elevation and sectional view of the natural hemp fiber drainage 30 having a plate-shaped cross section as a third embodiment. As a single natural palm fiber, a plurality of circular cores 11 'having a diameter of about 2 to 4 mm are arranged and sutures 13 are interposed between the circular cores 11'. Natural hemp fiber drainage with plate cross section can be adjusted in thickness and width according to design.

2 and 3, the material used in the conventional PD material method is a plate-shaped material is designed to be used as it is without modifying the existing pour equipment by considering the cost does not rise.

Example 1

The natural hemp fiber drainer of the present invention was prepared in a circular cross section. A natural palm fiber with a diameter of about 2 mm was twisted to form a core, and the core was wound with two layers of filter material, and one side was sewn to prepare a drainage material having a diameter of 31 to 33 mm.

Example 2

Twist about 2mm of natural palm fiber to make a core, and wrap the core with two layers of filter material to form a circle with a diameter of 20 to 24mm, and then seal the two to make an 8-shaped natural hemp fiber drainage. Was an average of 8.3 cm 2.

Example 3

Three natural palm fiber cores with a diameter of 2 to 4 mm are spaced apart, and the core is wound with two layers of filter material and sewn between the core and the core to be 110 mm wide (± 2 mm) and 8 mm thick (± 2). Mm) of plate-like natural hemp fiber drainage was produced and the average cross-sectional area was 8.15 cm 2.

A prototype according to the present invention was prepared and tested for physical properties. The test was carried out for the physical properties test and drainage capacity test of drainage material. The physical property test of drainage material is presented in <Table 1> and the drainage capacity test is shown in <Table 2>.

Physical property test value of drainage material (filter) Test Items Test result Test Methods FHWA ^{Note 1)} Minimum Standard Density (g / ㎡) 550-600 ASTM D3776 Grab tensile (kN)-dry sample 0.704 ASTM D4632 0.356 Grab tensile (kN)-wet sample 0.672 ASTM D4632 Tensile Strength (Ravelled Strip, kN)-Dry Sample 1.389 KS K 0520 Tensile Strength (Ravelled Strip, kN)-Wet Sample 1.223 KS K 0520 Mullen Burst Strength (kN / ㎡) 2050 ASTM D3786 898 Trapezoidal Tear (kN) 0.158 ASTM D4533 0.111 Elongation at Break (%)-Dry Sample 7.28 ASTM D4362 Elongation at Break (%)-Wet Sample 11.84 ASTM D4362 Permeability (m / sec) 3 x 10 ^-3 ASTM D4491 Aperture of size (㎛) 200 ASTM D4754 90-120

Note 1) The criteria set forth in the specification prescribed by the Federal Highway Authority (FHWA).

Note 2) The sample used for the test is the result of using a single layer of drainage material.

According to Table 1, the wastewater of the present invention satisfies all the minimum physical properties suggested by the US Highway Corporation, and shows no problem in using it as the wastewater.

Discharge Capacity Test Circle 8 figure Plate type Water discharge capacity (㎥ / year) 50 at 410,300 kPa pressure at 100 kPa pressure 300 at 100 kPa pressure 35 at 300 kPa pressure 16 at 200 k300 pressure at 100 kPa pressure Unit weight (g / m) 430 350 210

The construction method for promoting the consolidation of the soft ground using the natural hemp fiber drainage of the present invention according to FIG.

Similarly to the consolidation promotion method using the conventional vertical drainage as shown in Figure 4a, the sand layer 44 is laid in consideration of the ground pressure of the pouring equipment 41 on the surface of the soft ground 43. Natural hemp fiber drainage (10, 20, 30) is mounted to the pouring equipment 41 and inserted into the mandrel (mandrel, 42). And after pouring to a predetermined depth in the state which bonded the anchor (not shown) to the lower end of the natural hemp fiber drainage 10, 20, 30, a mandrel is drawn out. When drawing the mandrel, the drain is anchored in the ground by the drain bottom anchor and only the mandrel is drawn.

As shown in FIG. 4b, the natural hemp fiber drainage is poured into the required portion in the ground and then is deposited on the sand layer 44. The sedimentary soil creates vertical pore water pressure in the ground, causing the pore water in the ground to move to the relatively low pressure water drainage, and the pore water flows out through the drainage to the upper surface layer.

Provides the drainage material used for the soft consolidation promotion method of soft ground and the construction method using the above material, and the lack of efficiency and reliability of the band-type plastic drain process that wraps the existing plastic core with textile fibers The natural hemp fiber vertical drainage to solve the problem and to provide a consolidation promoting method using the same.

In addition, the present invention contributes to environmental conservation by preventing the contamination of the ground by environmentally friendly drainage method that is decomposed by microorganisms and finally assimilated with soil after a certain period of time after using the natural material as the drainage material after the drainage function. .

Claims (4)

A circular core 11 in which several strands of natural palm fibers are braided in a circle; Wow A two-ply jute material filter material 12 surrounding the circular core 11 in a circular shape and sealing one side thereof; Natural hemp fiber drainage of circular cross section, characterized in that configured as. At least two seals (13) made of a circular core (11) braided in multiple strands of natural palm fibers and a two-ply jute material filter material (12) wrapped in a circular shape. Natural hemp fiber drainage 20 of the eight-shaped cross section. A circular core 11 'having at least three arranged as a single natural palm fiber having a diameter of about 2 to 4 mm; And A two-ply jute material filter material wrapped around the circular cores 11 'in a plate shape and sealed between the circular cores; Plate-like natural hemp fiber drainage, characterized in that consisting of (30). Laying a sand layer 44 on the surface of the soft ground 43; Mounting any one of the natural hemp fiber drainage selected from claim 1, claim 2, claim 3 in the pouring equipment 41 and inserted into the mandrel (42); Fixing the natural hemp fiber drainage into the ground as the mandrel (42); Drawing the mandrel (42); Pile up soil on the sand layer 44; And Draining the ground gap water to the upper surface layer through the natural hemp fiber drainage; Consolidation promotion method using a natural hemp fiber drainage, characterized in that it comprises a.