JP6552847B2 - Wind resistance evaluation method for simple buildings and reinforcement method for simple buildings - Google Patents

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 members such as arch members, shoulder pipes, ridge pipes, and anti-sink pipes that compose the sides and the roof with connected parts such as setters and clamps. The end of is inserted into the ground and is fixed to the ground.

  When large wind pressure is applied to a simple building due to strong wind such as a typhoon or gust, a pulling force is applied to an arch member inserted into the ground. If this pulling force is greater than the force that the arch material can withstand without being pulled (hereinafter referred to as pull-out load resistance), the arch material is pulled out, and in the worst case, the simple building floats up and collapses due to the wind. In order to improve the wind resistance performance of a simple building, it is practiced to embed a reinforcing pile on the ground and connect the reinforcing pile and a frame member such as a settlement preventing pipe of the simple building (see Patent Documents 1 to 3).

  Various reinforcement piles have been proposed. For example, Patent Document 1 discloses a spiral pile having a wire rod formed in a spiral shape, and Patent Document 2 discloses a vertical wall portion that substantially vertically rises from a flat portion and both side ends thereof. Patent Document 3 proposes a screw pile in which a spiral blade is fixed in the vicinity of a tip end of an anchor pile consisting of a resistance plate having a and a body rod fixed to the resistance plate. 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. Any of the commercially available reinforced piles can not be deeply embedded because their length can not be adjusted. Therefore, in order to reinforce a simple building using a commercially available reinforcement pile, there is a problem that it is only necessary to increase the number of reinforcement piles to be embedded. Moreover, in the case of a soft ground, the pullout resistance of the reinforcement pile is often insufficient at a depth of about 30 to 70 cm, and there is a problem that the strength is hardly improved even if the number of reinforcement piles is 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 processed into a pointed shape;
And a screw screw provided in a spiral shape on the 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. The hollow tube is provided with one or more sets of bolt holes,
1. The pipe screw and the connecting pipe are connected to each other 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.
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. Assembled and constructed a frame material,
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 for fixing the simplified 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);
The wind resistance performance evaluation method of the simple building characterized by having.
"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
qu: Uniaxial compressive strength of cohesive soil [kN / m ² ]
qu = 12.5 N (Terzaghi Peck type)
N: N value. A numerical value indicating the strength of the ground determined by the standard penetration test (JIS A 1219).
Ls: Buried length of sandy soil [m]
Lc: Buried length of cohesive soil [m]
φ: Perimeter of arch material [m]
α: Safety factor. 2.0 for cohesive soil, 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 a simple building is constructed in a place where the strength of the surface ground is weak and the excellent strength is deeply located, the pipe screw pile of the present invention can be reinforced by connecting the pipe screw of the present invention with a connecting pipe of appropriate length. 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 the present invention can reach a stratum with excellent strength by deep embedding, the simple building can be reinforced 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. One or more sets of bolt holes are provided in the hollow pipe of the pipe screw, and the connecting pipe inserted into the hollow pipe can be firmly connected by the tip of the bolt passed through the bolt hole. . Reinforcement of a simple building requires many pipe screw piles, but in the pipe screw pile of the present invention, since the pipe screw as the tip and the joint pipe are composed of separate members, they are integrated as in the prior art Compared with the formed screw pile, it is easy to carry and the space required for carrying and storage can be reduced.

  Furthermore, the pullout resistance calculation value (tRa) of the arch material which fixes a simple building to the ground can be easily calculated by the standard index | surface called N value of a ground. Since the pullout force (T) acting on the arch material of the simple building by the wind of a specific wind speed can be calculated by the surface area of the simple building and the wind speed, the pullout resistance calculation value (tRa) and the pullout force (T) By comparing, the wind resistance performance of a simple building can be easily evaluated. In the past, there was a case where an unnecessary reinforcement pile was actually provided for the reason of "just in case", but a reinforcement pile is necessary by comparing the pullout resistance calculation value (tRa) and the pullout 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 performance, the wind resistance performance of the simple building can be improved by connecting the skeleton of the simple building and the reinforcing pile embedded in the ground. Since the number of reinforced piles necessary to impart desired wind resistance performance can be determined from the calculated pull-out resistance value of reinforced piles, unnecessary use of reinforced piles is avoided, and waste costs and labor can be suppressed. it can. If the ground surface N value is small, it may not be possible to provide the desired wind resistance performance no matter how much the number of commercially available reinforced piles is increased, but the pipe screw pile of the present invention uses a junction pipe of an appropriate length. As a result, since it can be reliably embedded in the stratum excellent in strength, desired wind resistance performance 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 present inventors focused on the existence of a stratum excellent in strength with which a large pull-out resistance can be obtained under the soil where a simple building such as a greenhouse is built, and completed the present invention as a result of earnest effort. . Although the pullout resistance of the soil greatly varies depending on the soil quality, the present inventors have succeeded in deriving a formula for calculating the pullout resistance of the soil by the standard index of N value of the soil as a result of intensive research. By using the standard index, we realized that we could build a simple building with the necessary pullout resistance. The present invention proposes a pipe screw pile capable of imparting the required strength to a simple building, a simple building reinforced with the pile, and a method of reinforcing the simple building using the pile.

Hereinafter, the present invention will be described in detail.
FIG. 1 shows an embodiment of a 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 pointed shape, and a screw blade 12 helically provided on the outer periphery of the hollow tube. The outer diameter and the inner diameter of the hollow tube 11 are not particularly limited, but the inner diameter is preferably 19 mm or more and the outer diameter 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 to plate with zinc, nickel etc. from the point of rust prevention. It is preferable to plate the inner surface of the hollow tube 11 as water may be accumulated inside the hollow tube 11, and an anticorrosive coating may be applied on the plating of the outer surface and the inner surface of the hollow tube 11. Further preferred. A commercially available product can be used without particular limitation as the anticorrosion paint, and for example, Super Chigi Wagad (manufactured by Watanabe Pipe Co., Ltd., registered trademark) can be used.

  The tip of the hollow tube 11 is processed into a pointed shape, and the hollow tube 11 itself is processed into a shape suitable for digging the ground, so there is no need to connect with a separate member for digging the ground, and the cost is low. It is. The shape of the tip of the hollow tube is not particularly limited, but as shown in FIG. 1, it is easy to lower the cost because the tip of the hollow tube is crushed into a flat shape and processed into a sharp shape by gas melting etc. 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. The area in which the screw vanes 12 and the hollow tube 11 are welded is large as compared with the area in which the screw vanes and the core material are welded in a conventional screw pile, so that 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 to plate with zinc, nickel etc. from a point of rust prevention, and it is more preferable to apply a rust preventive paint 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 on the outer periphery of the hollow tube 11 so as to draw a spiral of one or more cycles.

  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. By connecting the connecting pipe 2 of any length, it is possible to obtain the pipe screw pile 3 of the required length. Although the depth in which the pipe screw pile 3 of the present invention is embedded is not particularly limited, it is preferable to be embedded at 50 cm or more which is a common depth of soil formation. Further, the upper limit of the embedding depth is not particularly limited as long as it can be embedded in a stratum 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 joining pipe 2 into the hollow pipe 11, when the pipe screw pile 3 is embedded in the ground, it is possible to prevent the step between the hollow pipe 11 and the joining pipe 2 from being caught in a stone or the like 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, when the cross sectional shapes of the hollow pipe 11 and the joint pipe 2 are both polygonal and the outer surface of the joint pipe 2 is inscribed in the inner surface of the hollow pipe 11, the joint pipe 2 is embedded 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 line A-A 'of the pipe screw pile of one embodiment shown in FIG. As shown in FIG. 3, a pipe is provided by providing one or more sets of bolt holes 41 penetrating the hollow pipe 11 and sandwiching the junction pipe 2 inserted into the hollow pipe 11 with the tip of the bolt 4. 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. The pipe screw 1 and the joint pipe 2 can be easily connected using only the bolt 4 or the bolt 4 and the nut, so the pipe screw pile 3 can be assembled quickly at 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 piles 3 and the joint pipe 2 of the pipe screw pile 3 of the present invention are composed of different members, Compared to screw piles that are integrally formed, they can be easily transported, and the 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, and when embedding while rotating, and when extracting while rotating in the opposite direction to the time of embedding, 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 of the present invention is a layer with excellent strength by connecting with the connecting pipe 2 of appropriate length even when the strength of the surface ground is weak and the layer with excellent strength is deeply located. 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 of the present invention is enhanced in pullout resistance by being embedded in a stratum excellent in strength, so that a simple building can be reinforced without increasing the number of pipe screw piles 3. Alternatively, the arch member of the simplified building may be a connecting member composed of different members constituting the side portion and the top portion of the simplified building, and the joint pipe 2 of the pipe screw pile 3 may be a member constituting the side portion of the arched member.

  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 determined. From this wind pressure, the pullout force (T) acting on one arch material inserted into the ground is obtained, and the pullout resistance of the arch material is compared with the pullout force (T), and it is necessary to reinforce the simple building Can be evaluated. The assumed wind speed can be appropriately selected according to the place where the simple building is installed, the topography, etc. For example, in Kyushu, Shikoku, etc. where damage by typhoon is a concern, the surrounding area is surrounded by mountains The range of 20 to 35 m / s can be used in the area where there is little strong wind damage such as

  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 complicated to carry measurement equipment to the site where a simple building is to be built, to actually embed an arch material, and to measure the pull-out resistance. Therefore, even if it is a site where reinforcement piles are not actually needed, reinforcement piles are embedded "for just in case" to reinforce simple buildings, which is a problem of wasting unnecessary cost and labor. was there.

  The inventors of the present invention reported on the Ministry of Land, Infrastructure, Transport and Tourism No. 1113 of 2001 as a formula that can calculate the pull-out resistance calculation value (tRa) without actually measuring the pull-out resistance of the arch member as a result of earnest research. 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
qu: Uniaxial compressive strength of cohesive soil [kN / m ² ]
qu = 12.5 N (Terzaghi Peck type)
N: N value. A numerical value indicating the strength of the ground determined by the standard penetration test (JIS A 1219).
Ls: Buried length of sandy soil [m]
Lc: Buried length of cohesive soil [m]
φ: Perimeter of arch material [m]
α: Safety factor. 2.0 for cohesive soil, 3.0 for sandy soil.
However, the pull-out resistance calculation value (tRa) of the sandy soil whose N value is less than 10 is 0.

  The embedded length (Ls, Lc) of the arch material and the circumferential length (φ) of the arch material are determined by the standard and design of the simple building, so the N value of the ground on which the simple building is built 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. As described in detail below, in the pullout resistance calculation formula of Formula 1, the pullout resistance calculation value (tRa) calculated from the calculation formula is a value smaller than the pullout resistance value obtained by actual measurement, that is, Designed to be on the safe side.

  The N value is a value determined by the 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 impacts required to drop a 63.5 kg weight by 75 cm, strike it on 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 the Swedish-type 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. A viscous soil is a soil in which the proportion of fine particles (particles having a particle size of 0.074 mm or less) is more than 50%, and the viscosity is high and it is 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 into the same depth to the same N-value cohesive soil and sandy soil, the cohesive soil is larger in pullout resistance. 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.

  How much wind speed can a simple building have withstanding wind resistance by comparing the pulling out force (T) acting on the arch material of the simple building at a given wind speed and the calculated pulling out resistance value (tRa)? 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 pullout force (T) with the calculated pullout resistance value (tRa), it can be determined whether reinforcement is necessary without measuring the pullout resistance, so it is actually unnecessary. This saves the cost of purchasing a certain stake and the time it takes to embed it.

  If the pullout force (T) is larger than the pullout resistance calculation value (tRa), the simplified building can be made to have a desired wind resistance performance by connecting the reinforced pile embedded in the ground and the skeleton 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 pullout resistance equivalent to that of the screw pile because of 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 an actual ground where a simple building is to be built, it is not clear that the value of the pullout resistance of the pipe screw pile 3 will not be measured, but it is complicated to measure in practice. The harder the ground is (the larger the N value), the higher the pullout resistance, so it is assumed that the N value of the ground and the pullout resistance are proportional, and the calculated pullout resistance value (tRp) of the pipe screw pile 3 is calculated. The possible formula was calculated. In addition, since the pullout resistance (short-term) of the screw pile is 2000 N in normal upland soil according to horticulture standards, this value is set as the upper limit of the calculated pullout resistance value (tRp). A formula for calculating the pullout resistance of the pipe screw pile 3 is shown in Formula 2.

"Formula 2"
Calculated pull-out strength in cohesive soil tRp = 2000/3 × 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 multiple places of the ground which builds a simple building.

  In the same way as the pullout strength calculation formula of the arch member of Formula 1, the pullout strength calculation formula of the pipe screw pile 3 of Formula 2 is also a smaller value than the pullout strength value obtained by actual measurement, that is, the safety side It is calculated as follows.

  When the pullout force (T) of the arch member of the simple building is larger than the pullout resistance calculation value (tRa), the pullout resistance calculation value (tRp) of the pipe screw pile 3 determined by the above equation 2 is used to The number of pipe screw piles 3 required to compensate for the shortage (T-tRa) is determined. Specifically, assuming that the number of arch members inserted into the ground in a simple building is n and the number of required pipe screw piles 3 is m, the number (m) of required pipe screw piles 3 is calculated by the following equation 3 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 members inserted into the ground in simple buildings

  A simple building is obtained by embedding at a fixed interval the number of pipe screw piles obtained by the above equation 3 and connecting the pipe screw pile embedded in the ground and a skeleton material such as an anti-sink pipe or arch material that constitutes a 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 reinforcement pile of about 30-70 cm in length, a reinforcement pile is only embedded in the ground with small N value, and wind resistance may not be improved very much. In the pipe screw pile 3 of the present invention, it is preferable to use the pipe screw pile 3 of the present invention as a reinforcement pile because the length of the joint pipe 2 can be adjusted and embedded up to the formation having excellent strength of N value. . As described above, since the pullout resistance is significantly different between the cohesive soil and the sandy soil, the pipe screw pile 3 has the N value of 4 or more in the sandy soil until the formation where the N value is 2 or more in the cohesive soil It is preferable to embed up to the formation.

  The arch members from φ19.1 to φ42.7 and the pipe screw pile of the present invention were used as test bodies. A pull-out test was conducted to measure the pull-out resistance while the test body was embedded in the soil to a depth of 300 to 500 mm and pulled 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>
Place: Nakamitani character Nishihara 501, Omitama City, Ibaraki Prefecture
Soil quality: cohesive soil N value = 2.4 ··· Embedding length 500 mm
N value = 2.3 ... embedded length 300 mm

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

<Pullout test 3>
Location: Sanbu City, Chiba Prefecture Matsugayaguchi Soil Quality: Cohesive soil (sand mixed cohesive soil)
N value = 3.0 ... embedding length 500mm
N value = 2.6 ··· embedded length 300 mm

<Pullout test 4>
Location: Sanbu-shi, Chiba Matsugayaguchi soil quality: Sandy soil average N value = 11.5 ... embedded length 500mm

  Two thirds of the maximum value of the drawing force measured when drawing each test piece in the vertical direction was taken as a drawing resistance (short-term) experimental value. In addition, the draw-out resistance calculation value (tRa) was calculated by the above-mentioned equation 1, and the verification ratio of the pull-out resistance experimental value to the draw-out resistance calculation value was calculated (extraction resistance test value / extraction resistance calculation value). The results are shown in Table 3. Although the soil quality in pull-out test 3 was viscous soil, it is thought that the sand mixture is abundant and the property as sandy soil is dominant, so the pull-out resistance calculation value was calculated as sandy soil.

"Verification of pullout strength calculation formula 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 pull-out test 3 performed on sandy clay soil, verification ratio fell below the standard value 1.0 in 8 of 11 tests. Also, no. 29 showed 10 N which is the lowest pull-out resistance experimental value through all the tests, and there was almost no pull-out resistance.
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.

  There was almost no pull-out resistance in the pull-out test 3 conducted on a sand mixed cohesive soil having an N value of 3.0, and the pull-out test 4 conducted on a sandy soil having an N value of 11.5 had no problem in the formula. In the case of sandy mixed clay soil and sandy soil treated as sandy soil, the pullout resistance was set to 0 when the N value was less than 10.

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

"Verification of pullout strength calculation formula of pipe screw pile"
Table 4 shows pull-out resistance (short-term) experimental values of pipe screw piles and calculated pull-out strengths (tRp) of pipe screw piles calculated from the pull-out resistance calculation formula expressed by the above equation 2.

  The experimental values of the pullout resistance (No. 25, 37, 38, 42) of the pipe screw piles measured in the pullout tests 2 to 4 are the pullout resistance calculation calculated by the formula represented by Formula 2 at the same N value. 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 pipe 12 screw blade 2 joint pipe 3 pipe screw pile 4 bolt 41 bolt hole

Claims (3)

Calculating a pulling force (T) acting on an arch member for fixing the simplified 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);
The wind resistance performance evaluation method of the simple building characterized by having.
"Formula 1"
tRa = 4/15 × (R _F / α) × 2
R _F : Frictional force between arch material and surrounding ground [kN]
RF = (10/3 × N × Ls + 1/2 × qu × Lc) · φ
qu: Uniaxial compressive strength of cohesive soil [kN / m ² ]
qu = 12.5 N (Terzaghi Peck type)
N: N value. A numerical value indicating the strength of the ground determined by the standard penetration test (JIS A 1219).
Ls: Buried length of sandy soil [m]
Lc: Buried length of cohesive soil [m]
φ: Perimeter of arch material [m]
α: Safety factor. 2.0 for cohesive soil, 3.0 for sandy soil.
However, the pull-out resistance calculation value (tRa) of the sandy soil whose N value is less than 10 is 0. The wind resistance performance evaluation method according to claim 1 , wherein 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. A hollow tube having a tip end of the reinforcement pile which is crushed into a flat shape and processed into a sharp shape;
Simple of claim 2 in which the pipe screw and Tsugikan having an outer peripheral screw blade provided in one period or more helically of the hollow tube, characterized in that a pipe screw pile connected How to reinforce the building.