JP5075888B2 - How to strengthen residential ground - Google Patents

Description

  The present invention relates to a method for reinforcing a residential ground, and more particularly to a method for reinforcing a residential ground when there is no margin in the space around the floor area.

  In Japan, where the population density is high, the number of suitable land as residential areas has decreased in recent years, and soft ground is often reinforced and supplied. For this reason, conventionally, a means for reinforcing a soft ground by mixing a ground reinforcement such as pile driving or a cement-based improving agent or the like has been used. In Europe and other countries, when building railways, roads, etc. on soft ground, there is already a means to reinforce the ground by laying plastic sheets over a wide area and using the force of the sheets. It has been widely adopted for over 40 years. For example, it is widely applied to Eurostar routes, Autobahn, Siberian Railway routes, other port facilities and airfield ground reinforcement.

  However, the conventional means described above have the following problems, particularly in a dense and narrow residential area. The ground reinforcement such as the first pile driving causes a great deal of inconvenience to adjacent houses due to pile driving vibration and noise. In the second ground improvement, the improving agent to be mixed penetrates into the ground water and causes water pollution. In addition, these geotechnical works are costly and require a long construction period.

  In addition, the means for laying the sheet made of the third plastic is to apply a tense force to the entire wide sheet so that the concentrated weight of the construction is suspended by a hammock, so that the concentrated weight of the construction on the ground is It is dispersed throughout the laid sheet. The tension of the sheet is supported by the frictional force between the earth and sand and the whole sheet generated by the weight of earth and sand laminated on the entire large sheet. Therefore, in a dense and narrow residential site, the laying area of the sheet is limited by an adjacent house or the like, so that it is not possible to obtain a frictional force that generates a pressing force on the sheet.

Therefore, in order to solve such problems, the present inventors laid two spunbond nonwoven fabrics on the residential ground so as to cross each other, and fixed both ends of the nonwoven fabric to the ground with piles. The reinforcement method of the residential ground which throws away concrete on the both ends of the nonwoven fabric fixed with the pile and proposed the housing ground was proposed (refer patent document 1). By this method for reinforcing a residential ground, it is possible to provide an inexpensive method for reinforcing a residential ground that has little influence on the surrounding environment even when there is no margin in the space around the floor area.

Japanese Patent No. 3784770

  However, it has been found that the method for reinforcing a residential ground described in Patent Document 1 described above has further points to be improved from the experience of performing a large number of properties. That is, the spunbonded nonwoven fabric has advantages that it is not directional in strength, is strong against acids and bacteria, has high tear strength, and is inexpensive, but has a high elongation rate and low tensile strength.

  By the way, in the field of civil engineering, non-woven fabrics are often used. The first reason is requested from civil engineering specifications related to ground formation. That is, in the ground formation based on the civil engineering specifications, a soft ground improvement sheet is laid on the exposed road floor, and crushed stone is dropped onto the soft ground improvement sheet from a transporter such as a dump truck, for example. In such a case, the spunbonded nonwoven fabric is intertwined with the continuous long fibers that are unique to the nonwoven fabric and are thermocompression bonded together, so even if the crushed stone falls and breaks, only that part remains damaged and a large area Will not be affected. On the other hand, since the woven fabric is calibrated with vertical and horizontal threads, a part of the damage spreads over a large area as it is. For this reason, it is said that it is not preferable in the field of civil engineering to construct a large-scale area.

  The second reason is that in the field of civil engineering, an unpredictable earth pressure may occur, so use a non-woven fabric that stretches more than 40 percent and absorb this earth pressure to increase the amount of total energy absorbed. Designed to do. On the other hand, the woven fabric is characterized in that a high tensile strength can be secured at a low elongation rate, but it breaks at a low elongation rate. Therefore, the woven fabric cannot stretch greatly in the vertical and horizontal directions. Although the woven fabric stretches in an oblique direction, the tensile strength in the oblique direction cannot be ensured. For this reason, woven fabrics are not used in civil engineering work.

  However, the standard for non-uniform settlement for houses is that the slope of the house is less than 5/1000. If a non-woven fabric made of spunbond with high elongation and low tensile strength is laid, It has been found that it may be difficult to ensure a measure of this uneven settlement depending on the degree of softness of the house, or the magnitude and bias of the load on the base bottom of the house.

  In such a case, there are means for stacking a number of non-woven fabrics made of spunbond, but the cost of parts of the nonwoven fabric and the fixing means is increased, and the laying work period becomes longer. In addition, a method of changing the spunbond nonwoven fabric to a woven fabric using reinforcing fibers having a low elongation rate is conceivable, but fixing all four sides of the woven fabric takes time and labor. Moreover, since the unit cost of the reinforcing fiber is high, the part cost of the woven fabric using the reinforcing fiber becomes high.

  Therefore, the object of the present invention is to deal with a house having a large area and a large area, which has little influence on the surrounding environment, especially when there is no room in the surrounding area of the floor space, and which cannot be handled by the prior art. Another object of the present invention is to provide an inexpensive method for reinforcing a residential ground that can suppress the inclination of a house to less than 5/1000.

  In order to solve the above-mentioned problems, the inventor of the present application has conducted intensive research and experiments. As a result, instead of the conventional nonwoven fabric, a belt-shaped woven fabric in which warp yarns are arranged in the longitudinal direction is laid, and the warp yarn of this woven fabric is It discovered that the inclination of a house could be suppressed to less than 5/1000 by fixing both ends to the ground by a fixing means.

  Also, by laying a belt-like woven fabric with warp yarns arranged in the longitudinal direction so as to be perpendicular to each other, and fixing both ends of the warp yarns of the woven fabrics stacked above and below to the ground by fixing means, respectively , You can suppress the inclination of the house more. Furthermore, when adopting a fabric foundation, lay a belt-shaped woven fabric with warp threads in the longitudinal direction only in the area where the bottom base of the fabric foundation touches, and so that the warp threads are along the longitudinal direction of the fabric foundation. And the inclination of a house can be suppressed by fixing the both ends of the warp of this woven fabric to a ground with a fixing means.

The warp of the woven fabric is preferably made of reinforcing fibers, and the weft of the woven fabric is preferably made of general-purpose plastic. It is more preferable that the weft is a flat yarn and is woven so as not to cause a gap therebetween.

  Here, “laying a belt-like woven fabric” means that a single or a plurality of woven fabrics having a longer longitudinal direction than the width direction are stacked one on top of the other and arranged in one or a plurality of rows on the ground. The “both ends of the warp yarn of the woven fabric” means both side portions formed by the end portions of the warp yarn in the peripheral portion of the woven fabric. “Laying only the area where the bottom base of the fabric foundation is in contact with this warp thread along the longitudinal direction of the fabric foundation” means that a woven fabric having substantially the same shape as the bottom base of the fabric foundation is used. It means laying on the ground so that the warp of the cloth is parallel to the longitudinal direction of the bottom base of the cloth foundation.

  “Reinforcing fiber” is tough and has high rigidity, for example, vinylon fiber, aramid fiber, carbon fiber, basalt fiber, or high-molecular polyethylene fiber. “Fiber made of general-purpose plastic” means a fiber made of a synthetic resin which is low in material cost and can be easily formed into a fiber shape and is used in a large amount for general purposes. For example, polypropylene, polyester, or polyethylene resin is applicable. “Flat yarn” means a thread having a flat cross section.

Next, the operation of the method for strengthening a residential ground according to the present invention will be described with reference to FIG. That is, the supporting force of the ground when the woven fabric is laid out is three supporting forces, that is, q ₁ : Hammock effect by the tensile force of the woven fabric, q ₂ : Pressing effect by the woven fabric at both ends of the house foundation, and q ₃ : It becomes the one that added the supporting force of the ground itself. Among these, q ₁ : The hammock effect by the tensile force of the woven fabric is expressed by the formula (1) shown in FIG. 1 and is proportional to the tensile force: P of the woven fabric. Here, q _1, the tensile force to the fabric: P is applied, in an extended state by a predetermined size, are supported by sharing the load of the house. Therefore, if the stretch rate of the woven fabric is large, it will be balanced in the stretched state, and the settlement rate of the housing foundation will increase accordingly. Therefore, when the load on the housing foundation or the distribution of the supporting force of the ground is uneven, the inclination of the housing foundation becomes large.

  By laying a belt-like woven fabric with a large tensile strength and a low elongation rate compared to conventional nonwoven fabrics, with warp yarns arranged in the longitudinal direction, and fixing both ends of the warp yarns of this woven fabric to the ground by fixing means, The inclination of a house can be suppressed to less than 5/1000 even for a heavy house that could not be constructed by the prior art, a house with a large foundation area, or an extremely unsupported ground. In addition, it is possible to reduce the laying cost of the woven fabric by fixing the both ends of the warp of the woven fabric to the ground by the fixing means. In addition, when the load applied to the housing foundation is large, or when the ground support force is low, weaving fabrics with warp yarns arranged in the longitudinal direction are stacked one above the other so as to be orthogonal to each other, and the top and bottom weaving By fixing both ends of the warp of the cloth to the ground by fixing means, the inclination of the house can be suppressed. Furthermore, when adopting a fabric foundation, lay a belt-shaped woven fabric with warp threads in the longitudinal direction only in the area where the bottom base of the fabric foundation touches, and so that the warp threads are along the longitudinal direction of the fabric foundation. And the inclination of a house can be suppressed by fixing the both ends of the warp of this woven fabric to a ground with a fixing means.

  Use high-priced reinforcing fibers only for the warp of the woven fabric, use inexpensive general-purpose plastic for the weft, and fix the both ends of the warp of the woven fabric to the ground with fixing means. This makes it possible to reduce the manufacturing cost and laying cost of the woven fabric. By using a flat yarn for the weft of the woven fabric, it becomes easy to weave so that there is no gap between them while reducing the number of wefts, and such a woven fabric without such a gap is laid on the ground When this is done, it is possible to avoid a state in which the ground is exposed in the gap between the wefts, so that the view in the laid state is improved. In addition, it is not necessary to apply the above-mentioned civil engineering specifications for small-scale ground formation for residential buildings, and because crushed stones are laid and spread on the ground by human power, it is due to the fall of cracked stones or crushed stones No breakage or damage to the woven fabric.

It is explanatory drawing about an effect | action of the reinforcement method of a residential ground. It is a partially expanded plan view of a woven fabric. It is an expanded sectional view of the warp and weft of a woven fabric. It is a top view of the ground which laid the woven fabric and fixed both ends. It is sectional drawing of the ground which laid the woven fabric and fixed both ends. It is a top view of the ground which laid so that a woven cloth might mutually cross and fixed both ends. It is a top view of the ground applied to the fabric foundation which laid the woven fabric and fixed both ends. It is sectional drawing of the ground applied to the fabric foundation which laid the woven fabric and fixed both ends. It is a comparison figure of the tensile force and elongation of the woven fabric by this invention, and the nonwoven fabric by a prior art. It is sectional drawing of the ground used for the confirmation test of the reinforcement effect of a ground. It is a top view of the ground used for the confirmation test of the reinforcement effect of the ground. It is the specification of the woven fabric etc. used for the confirmation test of the reinforcement effect of the ground. It is a graph which shows the confirmation test result of the reinforcement effect of a ground.

  First, the woven fabric 1 used in the present invention will be described with reference to FIGS. As shown in FIG. 2, the woven fabric 1 is a prototype made based on the original idea of the inventor of the present application. The woven fabric 1 is a belt-shaped one having a width of 2 m in the longitudinal direction and is reinforced only to the warp 11. A vinylon fiber which is one of the fibers is used, and the weft 12 is woven using an inexpensive flat yarn made of polypropylene. The weft yarns 12 are woven so that there is no gap between them.

  As shown in FIG. 3 (A), the warp yarn 11 is obtained by twisting a plurality of vinylon resin fibers 11a, and the warp yarn having a fineness of 1670 dt is used. Here, the fineness is 1 dt = 10.00 m / g. Note that the warp yarn 11 has less twist of the vinylon resin fiber 11a in order to reduce the elongation rate. On the other hand, as shown in FIG. 3B, the weft 12 is a flat yarn made of polypropylene having a flat cross-sectional shape. The fineness of the warp yarn 11 and the weft yarn 12 is preferably 1000 dt to 1800 dt, respectively.

  Next, a method for reinforcing a residential ground using the woven fabric 1 described above will be described with reference to FIGS. 4 shows a case where the residential ground is looked down from above, and FIG. 5 shows a cross section of the residential ground. Three sides are close to the neighbor and the remaining direction faces the road. Shows a residential area with little room. In this building, a solid foundation 5 is used. Now, in this method of reinforcing the residential ground, first, the portion that becomes the solid foundation 5 of the building is excavated to a predetermined depth, the exposed bottom surface is crushed with a roller, and the cracked stone 6 is 10 Cm above it. Spread the thickness. Then, crushing gravel is thinly laid on it, and the vibrating roller is run about 8 times to make the surface of the crushed stone uniform and spread. Note that crushed stones may be laid instead of the cracked stones 6.

  Next, a plurality of rows of strip-shaped woven fabrics 1 are placed on the cracked stone 6 so as to be larger than the solid foundation 5 of the building, that is, four sides are located between the outside of the solid foundation and the boundary between the adjacent grounds. For example, five rows are laid parallel to each other. The woven fabric 1 is laid so as to overlap approximately 30 to 50 cm on both sides of each other. Then, both ends of the warp yarn 11 of the woven fabric 1 are respectively wound around the iron pipe 2, and the iron pipe is fixed to the ground by an iron pile 3 having hooks on the head at predetermined intervals. The iron pile 3 is piled in a state in which the woven fabric 1 is pulled and a tight force is applied. Next, on the both ends of the woven fabric 1 wound around the iron pipe 2, the discarded concrete 4 is struck to a width of 30 cm and fixed so that the urging force of the woven fabric is not loosened.

  In addition, after laying the woven fabric 1 and fixing both ends, the cracked stone 6 is laid again on the woven fabric without damaging the woven fabric, and the vibrating roller is run about 8 times. Make the surface uniform and spread. Finally, formwork, bar arrangement, concrete is placed, and the solid foundation 5 is formed. It should be noted that other members such as reinforcing bars can be used instead of the steel pipe 2 as long as they have rigidity and strength capable of applying a pressing force to the woven fabric 1.

  In FIG. 6, a plurality of rows of woven fabrics 101 equivalent to the above-described woven fabric 1 are laid, and a plurality of rows of equivalent woven fabrics are laid in an up and down double so as to be orthogonal to each other. A method for reinforcing a residential ground in which both ends of each warp thread are fixed to the ground with iron pipes 102, steel piles 103, and discarded concrete 104 for a plurality of heavy woven fabrics is shown. Thus, by laying the upper and lower double woven fabrics 101 so as to be orthogonal to each other, the tensile strength of these woven fabrics is enhanced, so that the load applied to the foundation of the building is large or the soft ground Even when the drag of the building is lower, the inclination of the building can be suppressed. 4 and 5 are numbered by adding 100 uniformly to the numbers shown in FIGS. 4 and 5 for the sake of convenience of reference.

  FIG. 7 shows a method for reinforcing a residential ground for a fabric foundation (continuous foundation) 205 employed in a relatively lightweight building. That is, the belt-like woven fabric 201 which is equivalent to the woven fabric 1 described above and larger than the width of the bottom plate of the fabric foundation 205 is disposed only in a range where the bottom plate of the fabric foundation contacts the ground, and the warp yarn is in the longitudinal direction of the fabric foundation. Lay in a grid pattern along the line. Then, both ends of the belt-like 201 are wound around the iron pipe 202, and the portions around which the woven fabric of the iron pipe is wound are fixed to the ground by the iron piles 203 each having a hook at the head, and then the iron pipe 202 is wound. On both ends of the woven fabric wrapped around the pipe, the discarded concrete 204 is beaten to a width of 30 cm, and fixed so that the tension of the woven fabric is not loosened. 4 and FIG. 5 are given the same numbers as the numbers shown in FIG. 4 and FIG. 5 plus a uniform number 200 for the convenience of reference.

  Next, with reference to FIG. 8, the construction procedure of the method for strengthening the residential ground for the cloth foundation 205 will be described. That is, first, a range wider than the ground contact area of the bottom base 205a of the fabric foundation 205 is excavated to a predetermined depth to form an inverted trapezoidal cross-sectional excavated portion 207, and the bottom surface of the excavated portion is covered with a roller. Roll it down and spread the cracked stone 206 on it to a thickness of 10 cm. Then, crushing gravel is thinly laid on it, and the vibrating roller is run about 8 times to make the surface of the crushed stone uniform and spread. Note that crushed stones may be spread instead of the split stones 206.

  Next, the strip-shaped woven fabric 201 is laid on the cracked stone 206 as described above, and both ends of the warp yarn of each woven fabric are fixed to the ground by the iron pipe 202, the iron pile 203 and the discarded concrete 204. . Then, the cracked stone 206 is spread again to a thickness of 10 cm on the woven fabric 201 laid. Then, crushing gravel is thinly laid on it, and the vibrating roller is run about 8 times to make the surface of the crushed stone uniform and spread. Note that crushed stones may be spread instead of the split stones 206. The cracked stone 206 is laid and hardened, the formwork is placed, concrete is cast to form the fabric foundation 205, and finally the excavated portion 207 is backfilled.

  In FIG. 9, the test result which measured the tensile strength and elongation about the woven fabric 1 mentioned above and the nonwoven fabric used by the prior art is shown, respectively. In addition, the woven fabric 1 mentioned above is woven using warp yarn 11 using a high-tensile fiber vinylon manufactured by Unitika Co., Ltd., and weft using a flat yarn made of polypropylene manufactured by Ebara Industries Co., Ltd. On the other hand, the non-woven fabric used was DuPont Co., Ltd. sold as Typer SF49 (registered trademark). This typer SF49 is a spunbonded non-woven fabric, which is a fiber reinforced by uniaxial stretching of a long fiber made of polypropylene, which is heated and bonded by four layers, and the intersection of the fibers is melt bonded. 0.46 mm. The tensile force (KN / m) on the vertical axis is the tensile force per unit width (1 m) in the direction perpendicular to the warp 11, and the elongation (mm) on the horizontal axis is the length in the direction parallel to the warp 11. The amount of elongation per 100 mm.

  As shown in FIG. 9, the woven fabric 1 used in the present invention has a tensile strength of about 8 times when stretched by 5 percent as compared with the nonwoven fabric used in the prior art, and the maximum tensile strength of the nonwoven fabric. The elongation at is about 0.4% of the nonwoven fabric. Therefore, it was confirmed that when the woven fabric 1 of the present invention is laid, it can be suppressed to an extremely small amount of elongation as compared with the case of laying the nonwoven fabric of the prior art.

  The test result compared with the prior art example about the effect of the reinforcement method of the residential ground by this invention is shown in FIGS. As shown in FIGS. 10 and 11, in this comparative test, first, a corner of a material storage place in a residential area was excavated by 50 cm, and a ground corresponding to a soft ground was created by embankment thereon. This created ground was divided into A, B, and C areas of about 2 m square each. Regions A, B, and C are not subjected to rolling pressure.

  For area A, leave the woven fabric and non-woven fabric without laying, and for area B, lay two layers of non-woven fabric made of spun ponds 2m wide and 2m long according to the conventional example. The four sides were fixed to the ground with iron pipes and iron piles. For the region C, one sheet of woven fabric 1 having a width of 2 m and a length of 2 m according to the present invention was laid, and the two ends of the warp of the woven fabric were fixed to the ground by the iron pipe 2 and the iron pile 3. In addition, in FIG. 12, the specification of the nonwoven fabric made from spun pond by a prior art example and the woven fabric 1 by this invention is shown, respectively.

Now, for the regions A, B, and C described above, a ground plate loading test in accordance with JGS 1521 was performed. In this test, a loading board with a diameter of 30 cm is pressed perpendicularly to the ground, and the load is increased or decreased stepwise with a hydraulic jack, and the amount of settlement at each load is measured. In this test, the actual load was changed to six levels of 1.0, 2.0, 3.0, 4.0, 5.0, and 6.0 kN (load strengths of 31.8, 63 , 95.5, 127.4, 159.2, and 191 kN / m ² ), the amount of settlement was measured at two locations, and the average value was obtained.

  FIG. 13 is a graph showing the test results described above, with the vertical axis representing the amount of ground subsidence and the horizontal axis representing the load intensity. As shown in this graph, it was confirmed that the residential ground reinforcement method using the woven fabric 1 according to the present invention can obviously reduce the amount of settlement of the soft ground compared to the conventional reinforcement method using the nonwoven fabric.

  The method for reinforcing a residential ground according to the present invention relates to a residential building because there is little influence on the surrounding environment when there is no margin in the surrounding space of the building floor, and the inclination of the house can be suppressed to less than 5/1000. It can be widely used in industry.

1, 101, 201 Woven fabric 11 Warp yarn 2, 102, 202 Iron pipe (bar-shaped member)
3, 103, 203 Steel pile (pile)
4, 104, 204 Discarded concrete 5, 105, 205 Solid foundation, Fabric foundation

Claims (5)

Lay up and down the belt-shaped woven fabric with warp in the longitudinal direction so as to be orthogonal to each other ,
A method for reinforcing a residential ground, characterized in that both ends of the warp yarns of the woven fabric stacked above and below are fixed to the ground by fixing means , respectively . A belt-shaped woven fabric with warps arranged in the longitudinal direction is laid only in the area where the bottom of the fabric foundation touches down, and this warp yarn is laid along the longitudinal direction of the fabric foundation ,
Method for reinforcing housing ground, characterized in that fixed to the ground the both end portions of the warp yarns of the upper Kio fabric by fixed means. In Claim 1 or 2, the warp of the woven fabric is made of reinforcing fibers,
The method for reinforcing a residential ground, wherein the weft of the woven fabric is made of general-purpose plastic . Lay a belt-shaped woven fabric with warp in the longitudinal direction,
A method for reinforcing a residential ground in which both ends of the warp of the woven fabric are fixed to the ground by a fixing means,
The warp of the woven fabric consists of reinforcing fibers,
The weft of the woven fabric is made of general-purpose plastic. The method for reinforcing a residential ground according to claim 3 or 4, wherein the weft is a flat yarn and is woven so as not to cause a gap therebetween.

Images