JP2016169546A - Pipe screw pile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pipe screw pile that is connected to a joint pipe with an arbitrary length to enable length adjustment.SOLUTION: A pipe screw includes a hollow pipe that has a tip worked in a pointed shape, and a screw blade that is spirally provided on the outer periphery of the hollow pipe.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a reinforcing pile for fixing a simple building such as a greenhouse to the ground.

  Simple buildings constructed by assembling frame materials are used as greenhouses, cherry houses, barns, and the like. A simple building is constructed by connecting and assembling frame materials such as arch materials, shoulder pipes, ridge pipes, and subsidence prevention pipes that compose the side and roof with connecting parts such as setters and clamps. The end of is inserted into the ground and is fixed to the ground.

  When strong winds such as typhoons and gusts apply a large wind pressure to a simple building, a pulling force is applied to the arch material inserted into the ground. When this pulling force becomes greater than the force that the arch material can withstand without being pulled out (hereinafter referred to as pulling strength), the arch material is pulled out, and in the worst case, the simple building is lifted by the wind and collapses. In order to improve the wind resistance performance of a simple building, a reinforcing pile is embedded in the ground, and the reinforcing pile and a frame material such as a settlement prevention pipe of the simple building are connected (see Patent Documents 1 to 3).

  Various types of reinforcing piles have been proposed. For example, in Patent Document 1, a spiral pile in which a wire rod is formed in a spiral shape, and in Patent Document 2, a vertical wall portion that rises substantially vertically from a flat portion and both side ends thereof. An anchor pile made up of a resistance plate having a main body bar fixed to the resistance plate and a screw pile in which a spiral blade is fixed in the vicinity of the tip is proposed in Patent Document 3. FIG. 4 is a spiral pile described in FIG. 8 of Patent Document 1, and FIG. 5 is a partially enlarged view of FIG. 3 of Patent Document 3, showing a screw pile connected to a frame material.

  Although these reinforcement piles are marketed, all are about 30-70 cm in length. Since all commercially available reinforcing piles cannot be adjusted in length, they cannot be embedded deeply. Therefore, in order to reinforce a simple building using a commercially available reinforcing pile, there is a problem that the number of reinforcing piles to be embedded must be increased. In addition, in the case of soft ground, the pullout strength of the reinforcing pile is often insufficient at a depth of about 30 to 70 cm, and there is a problem that the strength is hardly improved no matter how many the reinforcing piles are increased.

ACT 2-87401 JP 2006-161442 A JP 2008-263883 A

  This invention makes it a subject to provide the pipe screw pile which can adjust length by connecting with the connecting pipe of arbitrary length.

1. A hollow tube having a tip machined into a pointed shape;
A pipe screw having a screw blade spirally provided on an outer periphery of the hollow tube.
2.1. A pipe screw pile, characterized in that the pipe screw described in 1 and a connecting pipe are connected.
3. One or more bolt holes are provided in the hollow tube,
1. The pipe screw and the connecting pipe are connected by the connecting pipe inserted into the hollow pipe being sandwiched between tip ends of bolts passing through the bolt holes. Pipe screw pile as described in.
4). 1. It is embedded in a stratum that is located deeper than the soil and has excellent strength. Or 3. Pipe screw pile as described in.
5. It is constructed by assembling frame materials
1. the frame material; To 4. A simple building, wherein the pipe screw pile according to any one of the above is connected.
6). Calculating a pulling force (T) acting on an arch member that fixes the simple building to the ground at a predetermined wind speed;
Based on the following formula 1, a step of calculating a pulling-out strength calculation value (tRa) of an arch material that fixes a simple building to the ground,
Comparing the pulling force (T) and the pulling strength calculation value (tRa);
A method for evaluating wind resistance performance of a simple building.
"Formula 1"
tRa = 4/15 × (R _F / α) × 2
R _F : Frictional force between arch material and surrounding ground [kN]
R _F = (10/3 × N × Ls + 1/2 × qu × Lc) · φ
ku: uniaxial compressive strength of cohesive soil [kN / m ² ]
que = 12.5N (Terzagi Peck formula)
N: N value. A numerical value indicating the strength of the ground determined by the standard penetration test (JIS A 1219).
Ls: Embedment length of sandy soil [m]
Lc: Embedment length of cohesive soil [m]
φ: Perimeter of arch material [m]
α: Safety factor. 2.0 for cohesive soil and 3.0 for sandy soil.
However, the drawing strength calculation value (tRa) of sandy soil having an N value of less than 10 is assumed to be zero.
7.6. In the wind resistance performance evaluation method according to, when the pulling force (T) is larger than the pulling strength calculation value (tRa),
A reinforcing method for a simple building, comprising connecting a frame material constituting the simple building and a reinforcing pile embedded in the ground.
8). The reinforcing pile is 2. To 4. 6. A pipe screw pile according to any one of the above. Reinforcement method for simple buildings as described in 1.

  Since the pipe screw of the present invention can be connected to a pipe having an arbitrary length, a pipe screw pile having a desired length can be obtained. When building a simple building in a place where the strength of the surface layer is weak and the stratum with excellent strength is located deeply, the pipe screw pile is strengthened by connecting the pipe screw of the present invention to a suitable length of the pipe. It is possible to embed even an excellent formation. By connecting the pipe screw pile embedded up to the stratum having excellent strength and the frame material of the simple building with a clamp or the like, the wind resistance performance of the simple building can be improved. Moreover, since the pipe screw pile of this invention can reach | attain the stratum excellent in intensity | strength by embedding deeply, it can reinforce a simple building, without increasing the number of pipe screw piles.

  The pipe screw and the connecting pipe can be easily connected to each other at a site where a simple building is built to form a pipe screw pile. By providing one or more sets of bolt holes in the hollow pipe of the pipe screw and sandwiching the connecting pipe inserted into the hollow pipe at the tip of the bolt passed through the bolt hole, a strong connection can be achieved. . Many pipe screw piles are needed to reinforce a simple building, but the pipe screw pile of the present invention is composed of separate members for the pipe screw and the pipe at the tip, so Compared with the formed screw pile, it is easy to carry and the space required for carrying and storage can be reduced.

  Furthermore, the drawing strength calculation value (tRa) of the arch material that fixes the simple building to the ground can be easily calculated by the standard index called the N value of the ground. The pulling force (T) acting on the arch material of a simple building due to the wind at a specific wind speed can be calculated from the surface area of the simple building and the wind speed, so the pulling strength calculation value (tRa) and pulling force (T) are By comparing, the wind resistance performance of a simple building can be easily evaluated. Conventionally, a reinforcing pile that is not actually necessary has been provided for reasons of "just in case", but a reinforcing pile is required by comparing the pull-out strength calculation value (tRa) and the pull-out force (T). Therefore, it is possible to reduce costs and labor.

  When it is evaluated that the simple building does not have the desired wind resistance, the wind resistance of the simple building can be improved by connecting the frame material of the simple building and the reinforcing pile embedded in the ground. Since the number of reinforcement piles required to give the desired wind resistance performance is obtained from the calculated pull-out strength of the reinforcement piles, it is possible to reduce unnecessary costs and labor without using reinforcement piles more than necessary. it can. If the N value of the ground surface layer is small, it may not be possible to give the desired wind resistance performance no matter how many commercially available reinforcing piles are added. However, the pipe screw pile of the present invention uses an appropriate length of the pipe. Therefore, it is possible to reliably embed in a stratum having excellent strength, and therefore, desired wind resistance can be imparted.

The figure which shows the pipe screw of this invention. The figure which shows the pipe screw pile of this invention. Sectional drawing of the pipe screw pile of this invention. The figure which shows the conventional spiral pile. The figure which shows a mode that the conventional screw pile is connected with the frame material.

  The inventors of the present invention have focused on the existence of a stratum having excellent strength capable of obtaining a large pulling resistance under the soil where a simple building such as a greenhouse is built, and as a result of diligent efforts, the present invention has been completed. . Although the pulling strength of soil varies greatly depending on the soil quality, the present inventors have succeeded in deriving an equation for calculating the pulling strength of soil by a standard index called the N value of soil as a result of intensive studies. By using the standard index, we realized that a simple building with the required pulling strength could be constructed. The present invention proposes a pipe screw pile capable of imparting necessary strength to a simple building, a simple building reinforced with the pile, and a method of reinforcing the simple building using the pile.

The present invention is described in detail below.
FIG. 1 shows an embodiment of the pipe screw of the present invention. The pipe screw 1 of the present invention is characterized by having a hollow tube 11 having a tip processed into a sharp shape and a screw blade 12 spirally provided on the outer periphery of the hollow tube. The outer diameter and inner diameter of the hollow tube 11 are not particularly limited, but are preferably 19 mm or more and 22 mm or more. Moreover, the cross-sectional shape of the hollow tube 11 is not limited to a circle, and may be a polygon, such as a hexagon or an octagon.

  The material of the hollow tube 11 can be used without any particular limitation. For example, metals such as iron, stainless steel, aluminum, and alloys thereof are preferable from the viewpoint of strength, and iron is particularly preferable from the viewpoint of cost. Moreover, it is preferable that it plated with zinc, nickel, etc. from the point of rust prevention. Since water may accumulate inside the hollow tube 11, it is preferable to apply plating to the inner surface of the hollow tube 11, and to apply a rust preventive paint on the outer surface and inner surface of the hollow tube 11. Further preferred. A commercially available product can be used as the rust preventive paint without any particular limitation. For example, Super Chigiwa Guard (registered trademark, manufactured by Watanabe Pipe Co., Ltd.) can be used.

  The tip of the hollow tube 11 is processed into a sharp shape, and the hollow tube 11 itself is processed into a shape suitable for digging the ground, so that it is not necessary to connect to another member for digging the ground, and the cost is low. It is. Although the tip shape of the hollow tube is not particularly limited, as shown in FIG. 1, it is easy to manufacture and low-cost by crushing the tip of the hollow tube into a flat shape and processing it into a sharp shape by gas fusing or the like. is there.

  A spiral screw blade 12 is welded to the outer periphery of the hollow tube 11. In the pipe screw 1 of the invention, the outer diameter of the hollow tube 11 to which the screw blade 12 is welded is larger than the outer diameter of the core material to which the screw blade is welded in the conventional screw pile. Since the area where the screw blade 12 and the hollow tube 11 are welded is larger than the area where the screw blade and the core material are welded in the conventional screw pile, the processing is easy. And the hollow tube 11 can be firmly fixed.

  The material of the screw blade 12 can be used without any particular limitation, but is preferably made of metal such as iron, stainless steel, aluminum, and alloys thereof from the viewpoint of strength, and iron is particularly preferable from the viewpoint of cost. Moreover, it is preferable that it is plated with zinc, nickel, etc. from the point of rust prevention, and it is still more preferable to apply | coat an antirust coating on plating. A commercially available product can be used without particular limitation as the anticorrosive paint. The screw blade 12 has an outer diameter of 100 to 120 mm, and is formed so as to draw a spiral of one cycle or more on the outer periphery of the hollow tube 11.

  FIG. 2 shows an embodiment of the pipe screw pile 3 of the present invention. The pipe screw pile 3 includes a pipe screw 1 and a connecting pipe 2 connected to each other. A pipe screw pile 3 having a desired length can be obtained by connecting the connecting pipe 2 having an arbitrary length. Although the depth which embeds the pipe screw pile 3 of this invention is not restrict | limited in particular, It is preferable to embed 50 cm or more which is the depth of a general soil. Moreover, the upper limit of the embedding depth is not particularly limited as long as it is a depth that can be embedded in a strata excellent in strength, but is usually within 150 cm.

  The diameter of the connecting pipe 2 is not particularly limited, but the outer diameter of the connecting pipe 2 is preferably smaller than the inner diameter of the hollow pipe 11 of the pipe screw 1. By inserting the pipe 2 into the hollow tube 11, it is possible to prevent the step between the hollow pipe 11 and the pipe 2 from being caught by underground stones when the pipe screw pile 3 is embedded in the ground. Can do. In addition, the cross-sectional shape of the connecting pipe 2 is not particularly limited, and may be a circular shape, a hexagonal shape, a polygonal shape such as an octagonal shape, or the like, and may not be the same as the cross-sectional shape of the hollow tube 11. However, if the cross-sectional shapes of the hollow tube 11 and the connecting tube 2 are both polygonal and the outer surface of the connecting tube 2 is inscribed in the inner surface of the hollow tube 11, the connecting tube 2 is inserted when the pipe screw pile 3 is embedded. It is preferable because the force applied to rotate can be transmitted to the hollow tube by the surface.

  In the present invention, the means for connecting the pipe screw 1 and the connecting pipe 2 is not particularly limited. The bolt 4 is preferably used because it can be easily and firmly connected at a site where a simple building is assembled. FIG. 3 is a cross-sectional view taken along the line A-A ′ of the pipe screw pile according to the embodiment shown in FIG. 2. As shown in FIG. 3, one or a plurality of sets of bolt holes 41 penetrating the hollow tube 11 are provided, and the pipe 2 inserted between the hollow tubes 11 at the tip of the bolt 4 is sandwiched between the pipes The screw 1 and the connecting pipe 2 can be connected. Here, the set of bolt holes means two opposing bolt holes. In this structure, since it is not necessary to provide a bolt hole in the connecting pipe 2, it is low-cost. Also, one or more sets of bolt holes are provided in the connecting pipe 2 so as to penetrate the pipe, and the bolts passed through the bolt holes of the hollow pipe 11 and the connecting pipe 2 are screwed together with nuts. You may connect by.

  It is preferable to provide two or more sets of bolt holes 41 because the pipe screw 1 and the connecting pipe 2 can be firmly connected. Since the pipe screw 1 and the connecting pipe 2 can be easily connected using only the bolt 4 or the bolt 4 and the nut, the pipe screw pile 3 can be quickly assembled on the site where a simple building is built. Moreover, although many pipe screw piles 3 are required for reinforcement of a simple building, since the pipe screw pile 3 of this invention is comprised by the pipe screw 1 and the connecting pipe 2 by a separate member, it is conventional. Compared with a screw pile that is integrally formed, transportation is easy, and a space required for transportation and storage can be reduced.

  The pipe screw pile 3 of the present invention is embedded by being pushed into the ground while being rotated. In the pipe screw pile 3 of the present invention, the pipe screw 1 and the connecting pipe 2 are firmly connected. When the pipe screw 1 is embedded while being rotated, and when the pipe screw 1 is extracted while being rotated in the direction opposite to that when being embedded, the pipe screw 1 And the connecting pipe 2 will not come off. Here, when embedding the pipe screw pile 3 in the ground, if a force is applied to a place away from the connecting pipe 2, the moment increases, so that the connecting pipe 2 can be rotated with a small force. When the cross-sectional shape of the connecting pipe 2 is a polygon, the connecting pipe 2 can be rotated using a commercially available spanner or ratchet wrench. When the cross-sectional shape of the connecting pipe is circular, it can be rotated by a commercially available spanner or the like by attaching a metal fitting having a polygonal cross section to the upper part of the connecting pipe 2.

  The pipe screw pile 3 according to the present invention is a stratum having excellent strength by connecting to the appropriate length of the pipe 2 even when the stratum ground is weak and the stratum having excellent strength is located deep. Can be embedded. By connecting the pipe screw pile 3 embedded in the stratum having excellent strength and the frame material of the simple building with a clamp or the like, the wind resistance performance of the simple building can be improved. The pipe screw pile 3 according to the present invention can reinforce a simple building without increasing the number of pipe screw piles 3 because the pulling strength increases by being embedded in a stratum having excellent strength. Or it is good also considering the arch material of a simple building as a connection member which consists of a different member which comprises the side part and top part of a simple building, and the connecting pipe 2 of the pipe screw pile 3 may be a member which comprises the side part of an arch material.

  Here, the simple building is fixed by inserting the end of the arch material into the ground. From the surface area of the simple building, the wind pressure acting on the simple building at a specific wind speed can be obtained. From this wind pressure, the pulling force (T) acting on each arch material inserted into the ground is obtained, and the pulling strength of the arch material is compared with the pulling force (T). Can be evaluated. The assumed wind speed can be selected as appropriate according to the location where the simple building is installed, the topography, etc. For example, in Kyushu, Shikoku, etc., where damage from typhoons is a concern, 35-50 m / s, surrounded by mountains In areas where there is little damage from strong winds, such as the wind, a range of 20 to 35 m / s can be used.

  The pulling force (T) acting on the arch material at a predetermined wind speed can be calculated from the surface area of the simple building and the wind speed, but the pulling strength of the arch material cannot be obtained unless it is actually measured. However, it is cumbersome to carry a measuring device to the site where a simple building is built, and actually embed an arch material to measure the pulling strength. For this reason, even if it is actually a site that does not require reinforcement piles, the problem is that it is necessary to embed reinforcement piles to reinforce a simple building and to reinforce a simple building, which is a waste of cost and effort. was there.

  As a result of diligent research, the inventors of the present invention have been able to calculate the pulling strength calculation value (tRa) without actually measuring the pulling strength of the arch material. The following formula 1 was calculated based on the description of the bearing capacity calculation formula.

"Formula 1"
tRa = 4/15 × (R _F / α) × 2
R _F : Frictional force between arch material and surrounding ground [kN]
R _F = (10/3 × N × Ls + 1/2 × qu × Lc) · φ
ku: uniaxial compressive strength of cohesive soil [kN / m ² ]
que = 12.5N (Terzagi Peck formula)
N: N value. A numerical value indicating the strength of the ground determined by the standard penetration test (JIS A 1219).
Ls: Embedment length of sandy soil [m]
Lc: Embedment length of cohesive soil [m]
φ: Perimeter of arch material [m]
α: Safety factor. 2.0 for cohesive soil and 3.0 for sandy soil.
However, the drawing strength calculation value (tRa) of sandy soil having an N value of less than 10 is assumed to be zero.

  Since the arch material embedding length (Ls, Lc) and the arch material circumference (φ) are known from the standard and design of the simple building, the N value of the ground on which the simple building is built and its classification (cohesive soil) If it is known whether it is sandy soil or not, it is possible to calculate the pulling strength calculation value (tRa) using the above formula 1. In addition, as will be described in detail below, the pulling strength calculation formula of Formula 1 is such that the pulling strength calculation value (tRa) calculated from the calculation formula is smaller than the pulling strength value obtained by actual measurement, Designed to be on the safe side.

  The N value is a value obtained by a standard penetration test described in JIS A 1219 and represents the strength of the ground. The N value is a value represented by the number of hits required to drop a weight of 63.5 kg for 75 cm, hit the ground, and drive 30 cm. The greater the N value, the stronger the ground, and the greater the pulling strength.

  The N value can be known by a Swedish sounding test described in JIS A 1221. In addition, Table 1 shows a guideline for the N value described in “Guidelines for safety of underground pipe-type pipe houses (issued by the Japan Facility Horticultural Association)” (hereinafter referred to as horticultural standards).

  The ground is subdivided and classified into many types, but in order to calculate the drawing strength calculation value (tRa), it is only necessary to determine whether the soil is clayey or sandy. Cohesive soil is soil having a proportion of fine particles (particles having a particle size of 0.074 mm or less) of more than 50%, and is highly viscous and difficult to pass water. Sandy soil refers to soil with a coarse fraction (particles having a particle size of 0.074 mm or more) of more than 50%, which is not viscous and is rough and easy to pass water. When the same arch material is inserted at the same depth into viscous soil and sandy soil having the same N value, the viscous strength of the viscous soil is greater. That is, for clay soil and sandy soil, the clay soil has a high pulling strength and the arch material is difficult to be removed, and the sandy soil has a small pulling strength and the arch material is easily removed. Even if it is a cohesive soil, if it contains a lot of sand, treat it as sandy soil for safety.

  By comparing the pulling force (T) that acts on the arch material of a simple building at a given wind speed and the pulling strength calculation value (tRa), how much wind speed the simple building can withstand to wind speed Can be evaluated. When the pulling force (T) is smaller than the pulling strength calculation value (tRa), it is not necessary to provide a reinforcing pile because the arch material alone has sufficient wind resistance. By comparing the pulling force (T) and the pulling strength calculation value (tRa), it is possible to determine whether or not reinforcement is necessary without measuring the pulling strength, so this is not actually necessary. This saves the cost of purchasing a certain stake and the time it takes to embed it.

  When the pulling force (T) is larger than the pulling strength calculation value (tRa), the desired building has the desired wind resistance performance by connecting the reinforcing pile embedded in the ground and the frame material of the simple building. be able to. As the reinforcing pile, a conventional spiral pile, a screw pile, or the screw pipe pile of the present invention can be used. Here, the pulling strength of the spiral pile and screw pile is described in the “horticultural standards”. The pipe screw pile 3 of the present invention has a pulling strength equivalent to that of the screw pile due to its shape.

Below, although the case where the pipe screw pile 3 of this invention is used as a reinforcement pile is explained in full detail, the conventional spiral pile and a screw pile can also be used with the same method.
In the actual ground where a simple building is built, the value of the pull-out strength of the pipe screw pile 3 is not found to be measured, but it is complicated to actually measure. Since the pulling strength increases as the ground is harder (the N value is larger), it is assumed that the N value of the ground is proportional to the pulling strength, and the pulling strength calculation value (tRp) of the pipe screw pile 3 is calculated. The possible formula was calculated. In addition, since the pulling proof strength (short term) of the screw pile is 2000N in the horticultural standard, it is set as the upper limit of the calculated pulling proof strength (tRp). The drawing strength calculation formula of the pipe screw pile 3 is shown in Formula 2.

"Formula 2"
Calculated pulling strength in cohesive soil tRp = 2000/3 x average N value
(2000 if average N value> 3)
Calculated pulling strength in sandy soil tRp = 2000/8 × average N value
(2000 if average N value> 8)
In addition, an average (N value) means the average of the N value measured in several places of the ground which builds a simple building.

  Similar to the pulling strength calculation formula of the arch material of Formula 1, the pulling strength calculation formula of the pipe screw pile 3 of Formula 2 is smaller than the pulling strength value obtained by actual measurement, that is, the safety side. It is calculated as follows.

  When the pulling force (T) of the arch material of the simple building is larger than the pulling strength calculation value (tRa), the pulling strength calculation value (tRp) of the pipe screw pile 3 obtained by the above equation 2 is used to calculate the pulling strength. The number of pipe screw piles 3 required to make up for the shortage (T-tRa) is obtained. Specifically, where n is the number of arch materials to be inserted into the ground in a simple building and m is the number of pipe screw piles 3 required, the number (m) of pipe screw piles 3 required by Equation 3 below is obtained. It is done.

"Formula 3"
m ≧ n (T−tRa) / tRp (where m is an integer)
m: Number of pipe screw piles n: Number of arch materials to be inserted into the ground in a simple building

  By embedding the number of pipe screw piles obtained in the above equation 3 at regular intervals, and connecting the pipe screw piles embedded in the ground with the frame materials such as the subsidence prevention pipes and arch materials constituting the simple building, Can be reinforced so as to have a predetermined wind resistance.

  Here, when the drawing force (T) is larger than the drawing strength calculation value (tRa), the N value of the ground surface layer on which the simple building is built is often small. Therefore, even if it reinforces with the conventional commercially available reinforcement pile of about 30-70 cm in length, a reinforcement pile is only embedded in the ground with a small N value, and wind resistance performance may not improve so much. Since the pipe screw pile 3 of the present invention can be embedded up to a stratum having a large N value by adjusting the length of the connecting pipe 2, it is preferable to use the pipe screw pile 3 of the present invention as a reinforcing pile. . As described above, since the pulling strength differs greatly between the viscous soil and the sandy soil, the pipe screw pile 3 has a N value of 2 or more in the clay soil, and the N value of 4 or more in the sandy soil. It is preferable to embed up to the formation.

  The arch material from φ19.1 to φ42.7 and the pipe screw pile of the present invention were used as test specimens. A pull-out test was conducted in which the test specimen was embedded in soil to a depth of 300 to 500 mm and the pulling strength was measured while pulling out in the vertical direction. Table 2 shows a list of test specimens. All of the test specimens used were manufactured by Watanabe Pipe Co., Ltd., and “Tough” in Table 2 means the trade name “Tough Pipe”.

<Pullout test 1>
Location: 501 Nishihara, Nakanoya, Omitama City, Ibaraki Prefecture
Soil: Cohesive soil N value = 2.4 ... Embedding length 500mm
N value = 2.3 ... Embedded length 300mm

<Pullout test 2>
Location: Nishikawa soil, Futtsu City, Chiba Prefecture: Cohesive soil N value = 2.4 ... Embedding length 500mm
N value = 0.8 ... Embedded length 300mm

<Pullout test 3>
Location: Matsutake Valley, Sanmu-shi, Chiba Soil: Cohesive soil (sandy clay)
N value = 3.0 ... embedding length 500mm
N value = 2.6 ... Embedded length 300mm

<Pullout test 4>
Place: Matsutake Valley, Sanmu-shi, Chiba Soil: Sandy soil average N value = 11.5 ... Embedding length 500mm

  2/3 of the maximum value of the pulling force measured when each test piece was pulled in the vertical direction was taken as the pulling strength (short term) experimental value. Moreover, the drawing strength calculation value (tRa) was calculated by the above formula 1, and the test ratio of the drawing strength experiment value to the drawing strength calculation value (drawing strength experiment value / drawing strength calculation value) was obtained. The results are shown in Table 3. In addition, although the soil quality of the pull-out test 3 was a viscous soil, since many sands are mixed and the property as a sandy soil is considered to be dominant, the drawing strength calculation value was calculated as a sandy soil.

"Verification of calculation formula for pulling strength of arch material"
In the pull-out tests 1 and 2 performed on the clay, the test ratio was higher than the reference value 1.0 in 20 of 24 tests and lower than the reference value in 3 tests.
Looking at the distribution of the test ratio, many were collected between 2.0 and 4.0, and the average value of 24 tests was 3.4. Therefore, it was confirmed that there was no problem in the calculation formula.

In the pull-out test 3 performed with sandy clay, the test ratio was less than the standard value 1.0 in 8 of 11 tests. No. 29 shows 10N which is the lowest experimental value of pulling strength through all tests, and there was almost no pulling strength.
In the pull-out test 4 performed on sandy soil, the verification ratio exceeded the standard value 1.0 in all tests, and it was confirmed that there was no problem in the calculation formula.

  The pull-out test 3 performed on sandy soil with an N value of 3.0 has almost no pulling resistance, and the pull-out test 4 performed on sandy soil with an N value of 11.5 has no problem in the calculation formula. In the case of sand-mixed viscous soil and sandy soil treated as sandy soil, the pulling strength when the N value is less than 10 was set to zero.

  From the above results, the measured value of the pulling strength of the arch material shows a larger value than the pulling strength calculation value (tRa) calculated from the pulling strength calculation formula represented by Equation 1, that is, the drawing strength calculation value. It was confirmed that (tRa) is located on the safe side with respect to the actually measured pulling strength value.

“Verification of the calculation formula for pulling strength of pipe screw piles”
Table 4 shows experimental values of the pulling strength (short term) of the pipe screw pile and the calculated pulling strength (tRp) of the pipe screw pile calculated from the drawing strength calculation formula expressed by the above formula 2.

  The experimental value of the pull-out strength (No. 25, 37, 38, 42) of the pipe screw pile measured in the pull-out tests 2 to 4 is the pull-out strength calculation calculated by the formula expressed by Formula 2 when the N value is the same. It exceeded the value (tRp), and it was confirmed that this calculation formula is safe with respect to the test value.

1 Pipe screw 11 Hollow tube 12 Screw blade 2 Pipe 3 Pipe screw pile 4 Bolt 41 Bolt hole

Claims (8)

A hollow tube having a tip machined into a pointed shape;
A pipe screw having a screw blade spirally provided on an outer periphery of the hollow tube.   A pipe screw pile, wherein the pipe screw according to claim 1 and a connecting pipe are connected. One or more bolt holes are provided in the hollow tube,
3. The pipe screw and the connecting pipe are connected by sandwiching the connecting pipe inserted into the hollow pipe at a tip portion of a bolt passing through the bolt hole. Pipe screw pile as described in.   The pipe screw pile according to claim 2 or 3, wherein the pipe screw pile is embedded in a stratum superior in strength located deeper than the soil. It is constructed by assembling frame materials
A simple building in which the frame material and the pipe screw pile according to any one of claims 2 to 4 are connected. Calculating a pulling force (T) acting on an arch member that fixes the simple building to the ground at a predetermined wind speed;
Based on the following formula 1, a step of calculating a pulling-out strength calculation value (tRa) of an arch material that fixes a simple building to the ground,
Comparing the pulling force (T) and the pulling strength calculation value (tRa);
A method for evaluating wind resistance performance of a simple building.
"Formula 1"
tRa = 4/15 × (R _F / α) × 2
R _F : Frictional force between arch material and surrounding ground [kN]
R _F = (10/3 × N × Ls + 1/2 × qu × Lc) · φ
ku: uniaxial compressive strength of cohesive soil [kN / m ² ]
que = 12.5N (Terzagi Peck formula)
N: N value. A numerical value indicating the strength of the ground determined by the standard penetration test (JIS A 1219).
Ls: Embedment length of sandy soil [m]
Lc: Embedment length of cohesive soil [m]
φ: Perimeter of arch material [m]
α: Safety factor. 2.0 for cohesive soil and 3.0 for sandy soil.
However, the drawing strength calculation value (tRa) of sandy soil having an N value of less than 10 is assumed to be zero. In the wind resistance performance evaluation method according to claim 6, when the pulling force (T) is larger than the pulling strength calculation value (tRa),
A reinforcing method for a simple building, comprising connecting a frame material constituting the simple building and a reinforcing pile embedded in the ground.   The said reinforcement pile is the pipe screw pile in any one of Claim 2 to 4, The reinforcement method of the simple building of Claim 7 characterized by the above-mentioned.