JPH01165813A - Cylindrical fabric body for knotted pile - Google Patents

Abstract

PURPOSE:To attain improvement of work and economic efficiency for pile creation as well as to attain increase of pile's bearing power, by preparing a portion of expandable diameter made of a fabric having a prescribed breaking elongation in the circumferential direction, in a cylindrical fabric body, into which hydraulic slurry is injected for creation of a pile-shaped substance under the ground. CONSTITUTION:A cylindrical fabric body 1 for knotted pile is made, consisting a portion of expandable diameter B, made of a fabric having a 80% or more or breaking elongation in the circumferential direction, and a portion of non- expandable diameter A. At work execution the cylindrical fabric body 1 is inserted, with its tip 7 clasped by a special jig, into a drilled hole 6. At the upper end of the ground side of the cylindrical fabric body 1, a packer 3 for grounding of hydraulic slurry is installed and, at the same time, the tip of the cylindrical fabric body is secured with a fixing jig 4. Then, cementitious hydraulic slurry 5 such as cement milk, mortar or concrete is pressure-injected with a group pump. With this arrangement, the portion of expandable diameter B can be expanded transversely, forming a pile-shaped substance having the portion of expanded diameter.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a cylindrical fabric body for constructing embedded type flexible foundation piles used for improving soft ground in the field of civil engineering and construction, and more specifically relates to a cylindrical fabric body for constructing hydraulic slurry. By pressurized injection, any part in the longitudinal direction of the pile is expanded and expanded in diameter by the injection pressure.
This invention relates to a cylindrical fabric for knotted piles that dramatically improves the abrasion bearing capacity of piles and enables significant rationalization of pile material costs.

[Conventional technology]

As a method to improve the frictional bearing capacity of piles buried in soft ground, in the field of prefabricated pile embedding methods, prefabricated concrete piles of different diameters with concentric protrusions integrally formed on the outer circumferential surface of the pile are buried in excavation. There is also a method of screwing in a steel pipe pile with ready-made blades, which has plate blades attached in a helical pattern on the outer circumferential surface of the pile. A method for constructing a concrete pile having concentric protrusions, and furthermore, for example, JP-A-57-2471
As proposed in Publication No. 8, methods have been attempted in which piles with irregular cross sections (irregularities) are constructed by casting on site using flexible sleeves.

[Problem that the invention seeks to solve]

However, these conventionally proposed methods have various problems as described below, and are not necessarily rational. In other words, in the case of ready-made concrete piles of different diameters, the manufacturing cost of the pile itself and the cost of transporting it to the construction site are high, and the construction cost and construction period are increased due to the increase in the diameter of the excavated hole for sinking. There are functional defects such as the inability to fully draw out the original purpose of frictional bearing capacity due to loss of ground adhesion, and in the case of ready-made winged steel pipe piles, in addition to significantly higher pile material costs, there are problems such as corrosion. There is a fundamental problem.

Similarly to the former case, when constructing concrete pits using formwork during excavation, the cost of constructing the piles is significantly higher, and there are also problems such as insufficient frictional bearing capacity due to loss of adhesion to the ground. There is a flaw. Furthermore, when a flexible sleeve and steel pipe are used in combination, not only is a double injection pipe required to fill the flexible sleeve with hydraulic slurry, but the injection process is extremely complicated and complicated. It was complicated and lacked practicality. In addition, because the adhesion between the hydraulic slurry hardened body and the steel pipe is weak, it is better to use integrated piles (). There have been a number of problems with piles or pile materials.

An object of the present invention is to provide a cylindrical fabric for knotted piles that enables easy construction, reduction of pile material costs and construction costs, expansion and diameter expansion in arbitrary patterns, and improvement of frictional support. .

[Means for solving problems]

The present inventors focused on the good extensibility function under low stress of low-oriented fiber materials, such as undrawn yarns or low-drawn yarns of thermoplastic synthetic fibers, and applied this to the The inventors have discovered that the above object can be achieved by using it in the enlarged diameter section, and have arrived at the present invention.

That is, the present invention provides a cylindrical fabric body with a closed tip, which is used to inject a hydraulic slurry under pressure into the interior and harden it to create a pile-like object in the soil. It is characterized in that it consists of an enlarged diameter part and an enlarged diameter part, and the fibers forming the enlarged diameter part are made of fibers having a breaking elongation of 80% or more at least in the circumferential direction.

According to the present invention, a knotted pile having an arbitrary pattern of expanded diameter portions and having a high frictional bearing capacity can be formed in the soil using an easy construction method and at low cost.

The hydraulic slurry as used in the present invention refers to a cement mixture in a fluidized state, and typical examples thereof include cement milk, mortar, and concrete. The mixing ratio of water and additive materials to be mixed with cement can be determined by comprehensively considering the required material strength of the cured product, operability during injection, material cost, abrasion resistance strength of the fabric, water permeability of the fabric, etc. desirable.

In the present invention, the state in which the tip is closed refers to the end on the deep side of the pile built in the ground, that is, the end on the side opposite to the injection port, as shown by reference numeral 7 in Fig. 4. The closed state refers to the state in which the tip of the cylindrical fabric body 1 for knot piles is tied with a shaved knot or the like or closed with various jigs in order to prevent the injected material from leaking from the end opposite to the injection port. , or a state in which closure with a woven structure, etc. is applied. Any method may be used to close the side end portions as long as the closed portions are not destroyed by the internal pressure of injection of hydraulic slurry from the above-ground side, but considering the manufacturing cost of the cylindrical fabric body,
It is wise to use a tissue occlusion method that can minimize the loss of fabric associated with the provision of occlusion function.

The cylindrical fabric for knot piles of the present invention is a cylindrical fabric whose cross section exhibits a circular cross-sectional structure over the entire length in the fully stretched state, and which partially includes a portion with a large diameter. The initial shape before injection of the injection material is a straight or approximately straight cylindrical shape.

Means for obtaining a cylindrical structure include a seamless type air duct structure as shown in Fig. 6, a vent structure with ears consisting of a single layer and an air duct part as shown in Fig. 7, and a selvedge air duct structure as shown in Fig. For example, a cylindrical structure made by overlapping both ends of a sheet and sewing, gluing, fusing, etc., can withstand the injection pressure of the injection material filled into the cylindrical fabric. Any type may be selected, but from the viewpoint of obtaining high pressure resistance most rationally, it is more preferable to adopt a seamless type air channel structure that does not cause local stress concentration. In addition, the form of the fabric body may be a piece of paper, a knitted fabric, a net-like article, etc. Among them, from the viewpoint of the pressure resistance required in the present invention, the shape stability of the pile hardening body, and the prevention of leakage of the injection material, it is preferable to use a fabric. is most suitable, but it can also be applied to knitted fabrics, net-like fabrics, etc. depending on the combination of tissue structure, density, and lamination.

The non-expanded diameter portion in the present invention is the minimum diameter portion that should withstand the overlying compressive load, as shown in Fig. 1a, for example, and its diameter is determined by the composition of the injection material as well as the compressive strength of the hardened pile material. This is what determines the

In this non-expanded diameter part, the internal pressure of the cylindrical fabric on the ground is 0.
30% of the initial diameter of the cylindrical fabric in a state of 1 kg-f/cJ or more and less than 3.0 kg-f lct&
It is preferable to use a material that does not expand or expand in diameter. The fiber material used for this part is preferably a material with relatively low elongation, and preferably has a breaking elongation of less than 20%. From this point of view, suitable materials include:
There are many fibers to choose from, including polyamide fibers such as high-strength 6-nylon and 6-row nylon, polyester fibers, aramid fibers, polyolefin fibers such as high-strength polyethylene and polypropylene, and carbon fibers. Whether to do so may be determined based on cost, required pressure resistance, etc. These materials may be used alone or in combination. Further, the fineness, texture, and density of the material used are preferably determined by comprehensively taking into consideration the required compressive strength, water permeability, cost, etc. It is desirable that the elongation rate is less than 30% with respect to the initial diameter.
This is because the minimum diameter is inevitably determined by the injectability during slurry injection, and expanding the diameter by 30% or more will significantly increase the cost of the injection material, and the pressure resistance will decrease as the diameter increases.

The enlarged diameter part in the present invention is a part that plays a role of supporting the upper body without sinking along with the surface friction force of the non-expanded diameter part, and is expanded by the injection internal pressure. This part has the function of dramatically increasing the supporting capacity of the pile by expanding the diameter and increasing the cross-sectional area of the bulb. The shape of the expanded diameter portion is not particularly limited as long as it forms a concentric circle with the non-expanded diameter portion in the expanded state.
As for the number of locations, it is only necessary to provide at least one location.

Here, both the non-expanded diameter part and the expanded diameter part have the same initial diameter before the injection material is injected, or the expanded diameter part is slightly larger in a so-called straight shape, or is extremely similar to a straight shape. It is desirable that In this way, it is easy to sink the cylindrical fabric into the excavated hole, significantly improving construction workability, and reducing the drilling cost due to the reduction in the diameter of the excavated hole, and the fabric cost due to the reduction in the amount of fabric required. Effects such as rationalization can be obtained.

Next, regarding the setting of the diameter ratio in the fully expanded state of the non-expanded diameter part and the enlarged diameter part, which affects the bearing capacity, compressive strength, and injection material cost, the non-expanded diameter part has the minimum diameter that can withstand the overlying compressive load. This is preferable from the viewpoint of injection material and fabric cost.

On the other hand, it is preferable for the expanded diameter part to have a larger diameter expansion capacity in order to increase the supporting force, but from the viewpoint of fully expanding in the ground, it is 0.1 kg-f/cd or more than 3.0 kg-f on the ground.
It is desirable to be able to withstand internal pressures of less than /cd. Therefore,
It is desirable to decide the diameter configuration by taking these and the shear strength limit of the poured pile material into consideration, but according to the inventor's extensive experiments, the diameter expansion ratio of the diameter expansion part should be about 5 times or less at maximum. Furthermore, it has been found that approximately 3 times or less is preferable in practical terms. In addition, when a plurality of diameter enlarged parts are provided as shown in an example in FIG. Furthermore, the overall length of the cylindrical fabric, the individual lengths of the non-diameter portion and the expanded diameter portion, the arrangement pattern of both portions, the number of locations, etc. are determined based on the ground structure data to determine the most suitable design. It is better to do so.

As a means for compositely integrating the non-diameter expanded portion and the expanded diameter portion,
As shown in Fig. 2, only the threads in the circumferential direction of the cylindrical fabric are changed during weaving, as shown in Fig. 3; There is a method of sewing or gluing fabrics made of threads that differ only in the circumferential direction, but other methods may be used as long as they satisfy the required functions. Further, regarding the configuration of both parts, there is no question as to whether or not the fabrics are laminated. Furthermore, the fiber material forming the circumferential direction of the enlarged diameter portion may be one type or a combination of two or more types as long as it satisfies the specified elongation at break.

The circumferential direction in the present invention refers to the opposite elongated direction of the pile, that is, the direction in which the diameter or outer circumference is controlled when the cross-sectional shape is expanded into a circular shape, and corresponds to C in FIG. 6, for example. Taking a seamless cylindrical fabric as an example, this corresponds to the weft direction. The fibers that form at least the circumferential direction are defined here because in order to expand and expand a part of a straight cylindrical body, at least a high elongation behavior in the outer circumference is essential. Although high extensibility is not necessarily required in the longitudinal direction, high extensibility is preferable for smooth and stable diameter expansion.

It is necessary that the elongation at break of the fibers forming the expanded diameter portion of the present invention is 80% or more, preferably 100% or more.

The reason why the elongation at break needs to be 80% or more is that
If it is less than %, the maximum diameter expansion magnification will be less than 1.8 times,
This is because the cost advantage cannot be fully extracted from the relationship between the cost of the injection material and the supporting capacity.

In the present invention, the fiber having a breaking elongation of 80% or more means:
Breaking elongation is 80% regardless of material composition etc.
It refers to all of the above-mentioned fiber materials, regardless of whether they are a single material or a composite of two or more different materials. In addition, the fineness of the constituent fibers, the number of composite fibers, and even the composition form of the elongation mechanism, which is the key point of the present invention, such as unprocessed yarn, various crimped yarns, covering yarns, core yarns, braided cords, etc. The material is not limited as long as it satisfies the necessary pressure resistance in addition to the extensibility described above. According to the experiments conducted by the present inventors, it is possible to achieve both performance by using low-strength thermoplastic synthetic fibers such as low-magnification drawn yarns, high-speed spun yarns, high-extensibility false-twisted yarns, etc. for the weft or warp yarns. It can be an extremely effective means to satisfy the following. Here, the high-strength, low-magnification drawn yarn of thermoplastic synthetic fiber is 1.5 times to 2.0 Polyamide fibers such as 6-nylon or 6-row nylon obtained by hot drawing or cold drawing at a draw ratio of about
In addition, the elongation at break is approximately 100 to 150%. In addition, high-strength type 6~
Examples include polyamide t-crimped yarn obtained by pre-twisting a drawn yarn of nylon or 6-row nylon in a low twist range and then false twisting the yarn.

According to this method, a high-performance textured yarn having a breaking elongation of about 80 to 100% can be obtained.

Next, an example of a construction pattern in soil of friction piles of different diameters using the cylindrical fabric according to the present invention will be described in detail with reference to the drawings.

FIG. 1 is a schematic diagram showing the usage state (fully expanded state) of the cylindrical fabric for knot piles of the present invention, and FIGS. 2 and 3 show the non-diameter expansion of the cylindrical fabric for knot piles of the present invention. Fig. 4 is a schematic diagram showing an example of a method of integrating the section and the enlarged diameter part, Fig. 4 is a schematic diagram showing the state in which the cylindrical fabric for knot piles of the present invention is inserted into an excavated hole, and Fig. 5 is a schematic diagram showing the completed section. 6, 7, and 8 are longitudinal cross-sectional views showing how the friction piles of different diameters are integrated with the ground in the soil, and FIG. FIG. 2 is a schematic diagram showing an example of a diameter expansion pattern according to another embodiment of the present invention.

The cylindrical fabric body 1 for knot piles of the present invention, as shown in FIG.゛ is provided. The fibers forming the enlarged diameter portion B are made of fibers having a breaking elongation of at least 80% or more in the circumferential direction, as described above. The straight or substantially straight-shaped cylindrical fabric body 1 is formed such that the initial diameters of the non-expanded diameter portion A and the expanded diameter portion B are -.
As shown in the figure, the closed end portion 7 is grasped with a special jig and inserted into an excavated hole 6 which has been drilled with a diameter slightly smaller than the initial diameter of the cylindrical fabric. , a hydraulic slurry injection packer 3 is provided at the upper end of the above-ground side of the cylindrical fabric body.
Attach and secure. - On the other hand, the underground end of the cylindrical fabric is fixed to the hole bottom 9 by a fixing jig 4. Next, a cement-based hydraulic slurry 5 selected from among cement milk, mortar, concrete, etc. is injected under pressure through the Parakara using a pressure pump. The cylindrical fabric body begins to expand while pushing out the surrounding soil wall 8 by the hydraulic slurry injected under pressure, and in the first step, it is shaped into a shape approximating a circular cross section in order to fill the initial diameter of the straight state. Expanded. When the hydraulic slurry is further injected, the enlarged diameter part B made of a highly extensible fiber material having a breaking elongation of 80% or more in the circumferential direction starts to expand in the diametrical direction, and the non-expanded diameter part A starts to expand in the diametrical direction. A projection portion having a large diameter is integrally molded concentrically with the non-diameter expansion portion in the direction. Next, when the injection is completed, the pressure in the cylindrical fabric is slightly reduced, the injection packer is removed, and the injection operation is completed, but the hydraulic slurry filled in the cylindrical fabric will soon harden. As shown in FIG. 5, a friction pile of different diameters, which is completely integrated with the consolidated earth wall 10 and has an extremely high frictional bearing capacity, is completed in the soil. Since the present invention is constructed as described in detail above, it is possible to easily and rationally construct friction piles of different diameters in the soil, and at the same time, it is possible to obtain high frictional bearing capacity at low cost.

Next, the present invention will be explained using specific examples, but the present invention is not limited to these in any way.

Example 1 Using a shuttle loom, the warp yarns had a breaking elongation of 18% and a strength of 10.
5g/d 6 row nylon 1260d, 4 plied twisted yarns (8
0T/M), the non-expanded diameter part of the weft is the same as the warp, and the expanded diameter part is a high-strength type 6-row nylon undrawn yarn, drawn at a draw ratio of 1.70 times.The apparent fineness is 3910d, and the elongation at break is 3910d. 138%, low drawn yarn with a strength of 5,3 g/d (
80T/M) respectively, and the warp x latitude density is 15 x 15
Book/inch, texture is plain weave, initial diameter is 30cmφ, total length is 5
．． A straight-shaped seamless cylindrical fabric was woven with a length of 5 m and a non-expanded diameter part for closing the tip at 0.5 m on the distal end side, followed by a 1 m expanded diameter part and a 4 m non-expanded diameter part.

Next, a 0.5 m portion from the leading edge of the cylindrical fabric was used to close the leading end with a shaved knot. This cylindrical fabric with its tip closed is fixed in the excavation of soft ground with an N value of 3, which has been excavated through a hole diameter of 20 cm, by the method shown in Fig. 4, and cement/ Good quality mortar with a sand ratio of 1:2 was injected under pressure using a pressure pump with a discharge capacity of 801/min, and the injection operation was terminated when the internal pressure in the cylindrical fabric reached 5.0 kg-f/cA. Once the injection was completed, the internal pressure was reduced slightly, the backer was removed, and all pile driving was completed.The time required from sinking the cylindrical fabric to completion of the pile driving was approximately 10 minutes, making the pile driving extremely quick. Ta.

Thereafter, when the piles integrated with the earthen wall were cured for 28 days and a loading test was conducted, an extremely high frictional bearing capacity of 22 tons/piece was obtained.

After that, we pulled the antibody out of the soil and confirmed its shape, and found that it had a total length of 5m and a bulbous protrusion with a diameter of 66cmφ with a roughly circular cross-section at the tip, and a diameter expansion magnification of 2.2.
A friction pile with a different diameter, which is a big brother, has been completed. Furthermore, no leakage of mortar from the gaps between the fabric threads integrated on the surface of the cured product was observed.

The injection mortar cost per ton of supporting force was 0.70 in Example 1, which was extremely low, assuming that the 30 cmφ straight straight shape of Comparative Example 1, which will be described later, was 1. In addition to this, since the supporting force per pile was twice that of the straight type of Comparative Example 1, it is clear that this is extremely advantageous in terms of construction cost and tubular fabric cost.

Comparative Example 1 Using the same loom as in Example 1, 6-row nylon 1260d with a breaking elongation of 18% and a strength of 10.5 g/d and 4 twisted yarns (80T/M) were used for the warp and weft, respectively, and the warp
Weft density is 15 x 15 pieces/inch, texture is plain weave, initial diameter is 3
0cmφ, total length including 0゜5m of tip closure part is 5.5m
A straight-shaped seamless tubular fabric was woven. Next, after closing the tip in the same manner as in Example 1,
．． The injection operation was completed when the internal pressure of 0 kg-f/cnl was reached, and the same evaluation as in Example 1 was conducted.

The injection mortar cost per n also became relatively high.

Example 2 A straight-shaped seamless tube woven in exactly the same manner as in Example 1 except that high-strength 66-nylon undrawn yarn (apparent fineness 6630 d, breaking elongation 410%) was used as the weft in the expanded diameter part. When filling the mortar with a woven fabric until the internal pressure reached the point of 5.0 kg-f/cd in the same manner as in Example 1 and Comparative Example I, the required pouring time was approximately 12 minutes, indicating extremely rapid pouring. was completed. Also, the result of the loading test is 2
As a result of 7tb, the cross-sectional shape at the tip is approximately circular and the diameter is 83.
■A superior friction pile of different diameters with a diameter expansion ratio of 2.8 times, which integrates a φ bulb-like protrusion, has been completed. Also, as in Example 1, no mortar leakage was observed from the gaps between the fabric yarns, and the supporting force was 1 t.
The mortar cost index per on was also 0.75 and Example 1
Although it was slightly higher than that of Comparative Example 1, it was reasonable when compared with Comparative Example 1. Furthermore, since the bearing capacity per pile is extremely high, it can be said that the practical value is higher than that of Example 1.

Comparative Example 2 A semi-drawn yarn (80T/M) with an apparent fineness of 2720 d and a breaking elongation of 61%, which was made by stretching an undrawn yarn of high tenacity 66-nylon at a stretching ratio of 2.45 times, was used as the weft of the enlarged diameter part. When the same mortar injection evaluation as in Example 1.2 and Comparative Example 1 was performed using a straight-shaped seamless cylindrical fabric produced in the same manner as in Example 1 except for this, the maximum diameter of the bulb part was 4.
5 cmφ, diameter expansion ratio 1.5 times, bearing capacity per pile is 14 tb, cost index is 0.95, which tends to be slightly better than the straight type of comparative example 1, but bearing capacity per pile The rate of increase in the mortar cost index was as small as about 25%, and the rate of decrease in the poured mortar cost index was also as small as 5%, which was not satisfactory in practical terms.

〔Effect of the invention〕

According to the present invention, the expanded diameter portion is housed with a small initial diameter and is configured to expand and expand due to the injection internal pressure, thereby reducing the diameter of the excavation hole and making it easier to sink the cylindrical fabric. , it is possible to enlarge the diameter of any part, reduce the cost of the injection material, and obtain a high frictional bearing capacity, resulting in a friction pile with different diameters that is excellent in both functionality and economy. If the cylindrical fabric of the present invention is used, it can be effectively used as a means for rationally manufacturing ready-made concrete piles of different diameters, and the range of use is extremely wide.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing the usage state (fully expanded state) of the cylindrical fabric for knot piles of the present invention, and FIGS. 2 and 3 are non-diameter enlarged portions of the cylindrical fabric for knot piles of the present invention. Fig. 4 is a schematic diagram showing an example of the method of integrating the cylindrical fabric for knot piles of the present invention with the enlarged diameter part, and Fig. 5 is a schematic diagram showing the state in which the cylindrical fabric for knot piles of the present invention is inserted into an excavated hole. 6, 7 and 8 are schematic diagrams illustrating the method of forming a cylindrical fabric body into a cylinder, and FIG. It is a schematic diagram which shows an example of the diameter expansion pattern of another Example of this invention. DESCRIPTION OF SYMBOLS 1... Tubular fabric body for knot piles, 2... Sewing part, 3...
Hydraulic slurry injection packer, 4...fixing jig, 5
... Hydraulic slurry, 6... Excavation hole, 7... Blocked part, 8... Earth wall, 9... Hole bottom, IO... Consolidated earth wall, 11... Hydraulic slurry A: Non-expanded diameter portion, Ao: Non-expanded diameter portion for tip closure, B: Expanded diameter portion, C: Circumferential direction, P: Tonosho. Agent Patent Attorney Takeshi Kawakita Fig. 1 Fig. 2 Fig. 1 section pile cylindrical fabric Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 8 Fig. 7 Fig. 9

Claims (1)

[Claims] (1) Inject hydraulic slurry under pressure and harden it,
A cylindrical fabric body with a closed tip for creating a pile-like object in soil, the cylindrical fabric body consisting of a non-expanded diameter portion and an expanded diameter portion, and fibers forming the expanded diameter portion. A cylindrical fabric for knot piles, characterized in that the fabric is made of fibers having a breaking elongation of 80% or more at least in the circumferential direction.