JP4363597B2 - Solid foundation method - Google Patents

Description

The present invention relates to a stable material with mat foundation construction method to suppress differential settlement.

  In soft ground, due to the nature of cohesive soil, if uneven settlement occurs due to consolidation or plastic deformation, the use of the building will be hindered. In the case of soft ground, there is uneven settlement and the rigidity of the foundation is small, so splitting occurs when an earthquake occurs, causing significant damage to the building. Solid foundations, friction pile driving, or a combination of both is used as a foundation method when some subsidence is allowed. For example, when building a house, etc., excavating the foundation installation part to form underground beams (for example, Patent Document 1), collecting a geological sample of the excavation part and inspecting the composition and moisture content of the ground soil Then, ground improvement materials such as cement milk, mortar, bentonite, water glass, fiber, sand, etc. are added to the excavated part and compacted by a machine to form a groove for installing the foundation to form a foundation structure made of precast concrete Or has been done. (For example, Patent Documents 1 and 2)

Japanese Patent Laid-Open No. 3-96520 (page 2, left column, lines 4 to 20, lines 6 and 7) JP-A-5-280036 (page 3, right column 12-17, page 4, left column lines 33-35, FIG. 2)

  When excavating the foundation of a house foundation to form underground beams instead of the conventional cloth foundation method, the amount of excavated soil increases, the rigidity of the foundation itself is small, and work such as formwork and bar arrangement There are many man-hours. In addition, a solid foundation method in which a foundation structure made of precast concrete is formed by forming a foundation installation groove after compaction, or a foundation structure and a friction pile are used in combination, is expensive and cannot be shortened.

  In general, when building a house, etc., plan excavation of a predetermined width in the area of the site area, and run a machine that compacts the vibrator and soil for the groove (the width is constant) (even manually) The soil inside the groove (lower part) is pressed and compacted for 2 meters or more from the ground surface. As an indicator, the allowable stress level of the ground and the allowable bearing capacity of the foundation pile are obtained according to Notification No. 1113 (hereinafter referred to as Ministerial Ordinance) issued on July 2, 2001, which was promulgated based on Article 93 of the Building Standards Law Enforcement Ordinance. For this purpose, a method for determining the allowable stress level of the ground and the allowable bearing capacity of the foundation pile based on the results of the ground survey by the Swedish sounding method is established.

  The present inventor previously excavated a groove for stabilizing material adjustment with the width and depth adjusted by the strength of the ground near the foundation construction part in Patent No. 2797066 and Utility Model Registration No. 3059058, and at the same time, After replacing the soil with mixed soil, roll the soil replacement part with a rammer, etc. to create a stable material with improved soil quality, and after fixing the solid foundation reinforcement on the top surface of the stabilizer, the concrete We invented a foundation method with a stabilizer that was cast and integrated with a stabilizer and a solid foundation.

The present invention is based on the above-mentioned patent construction method and, as a result of intensive research on the Swedish sounding construction method, was created to further improve the soil strength and prevent the uneven settlement of buildings due to the weakness of the foundation ground. Te, aims at risk of differential settlement less, to provide a low cost solid foundation construction method of assuming an equal subsidence.

In order to achieve the above object, the invention described in claim 1
A solid foundation method for building a solid foundation for buildings on the ground,
A first test step in which a Swedish sounding test is performed as a test for confirming the allowable stress level of the ground at several places where the building foundation (10, 12) of the building is constructed;
In the place where the housing foundation (10, 12) is constructed, the recessed portion (h) is formed so as to include the place where the test was performed in the first test step by performing a construction that applies rolling pressure and vibration. And forming a reinforced ground forming step for strengthening the ground below the recessed portion (h),
A second test step for performing a Swedish sounding test in the same manner as the first test step at the location where the test was performed in the first test step, with respect to the ground reinforced in the reinforced ground creation step,
Filling the indented portion (h) with a cement mixture obtained by mixing on-site soil and cement solidifying material;
A solid foundation construction method including a step of constructing a solid foundation integrated with the cement mixture by placing concrete on top of the cement mixture,
It is said that.

  The invention according to claim 2 is the solid foundation method according to claim 1, further comprising a step of placing a fabric foundation on or near the cement mixture.

  The invention according to claim 3 further includes a step of giving the cement mixture a soil strength by hardening the cement mixture before the step of constructing the solid foundation. Has been.

  In this way, the present invention integrates a stabilizer and a solid foundation by placing a solid foundation on the upper surface of a soil improvement foundation part or a ground improvement part (stabilizer) having a soil strength and placing concrete. Therefore, it is a new and appropriate method for strengthening the limited ground as the foundation of a house.

  Normally, when applying vibration and rolling pressure, a rammer was used. However, the rammer is used only for rolling after backfilling and leveling the ground, and compacting the ground to a predetermined depth. not being used.

  The present invention plans a groove having a predetermined width in the area of the site area to be constructed, and runs a vibrator and a machine for compacting the soil before the construction of the housing foundation construction part. Swedish sounding as defined by Notification No. 1113 on July 2, 2001, which was promulgated under Article 93 of the Building Standards Law Enforcement Ordinance with the effect of rolling and compacting the soil below 2 meters above the surface. In accordance with the construction method, a ground survey is conducted to determine the allowable stress level of the ground and the allowable bearing capacity of the foundation. Based on the results, the allowable stress level of the ground and the allowable bearing capacity of the soil improvement foundation (that is, the stabilizer) are determined. After confirming, filling the soil that was indented by the rolling pressure of the upper groove of the soil improvement foundation with the soil mixed with ground soil and cement solidification material, and compacting, 1 kilometer deeper than 2 meters from the bottom of the foundation new Soil improvement foundation which scuttled reinforced so as not to following down the (stable material) build. Further, the solid foundation construction method is characterized in that a solid foundation reinforcement is arranged on the upper surface of the stabilizer, and the ground improvement portion (stabilizer) and the solid foundation are integrated by placing concrete.

To explain in more detail, before the construction of the housing foundation construction part, as a machine that compacts the vibrator and the soil, for example, using a Swedish sounding machine, after confirming the strength of the ground, the foundation construction part on the recessed ground by the sounding test The soil is mixed with soil and cement solidified material, and the Swedish sounding method is performed at the same place as before construction to confirm the effect. In this way, the minimum soil strength σc = 3.0 t / m ² (long-term) based on the above-mentioned ministerial ordinance can be expected by compacting the soil portion by rolling and imparting soil strength to improve the soil quality. It becomes the ground, and a solid foundation for the house is created above the predetermined groove. At this time, due to vibration and rolling pressure, the part that is recessed from the ground surface is finally mixed with soil and cement solidified material on the ground and given rolling strength by rolling pressure etc. to the predetermined ground surface to give strength. . In order to give vibration and rolling pressure, it is usually done with one machine, the working time per machine is adjusted by the ground, and sufficient measures are taken for soundproofing measures etc. to the neighborhood.

  As described above, according to the present invention, after testing the strength of the ground using a machine that compacts the vibrator and the soil before construction of the housing foundation construction part, for example, a Swedish sounding machine, a predetermined groove is planned on the ground beforehand. Then, by operating a machine with the effect of vibration and rolling in the groove, the ground is strengthened so that it does not fall below 1 kilonewton self-sink at a depth of 2 meters or more as specified in the Ministerial Ordinance. Fill the part below the standard ground with soil mixed with soil of the foundation construction part and cement solidified material, and make a stable material with the soil strength by compaction, and solid foundation reinforcement on the upper surface of the stabilizer Since it is placed and integrated with concrete, the soil surrounded by the ground improvement part (stabilizing material) and the solid foundation by the stable ground becomes a rigid body, and the uneven settlement of the building can be prevented.

  Traditionally, it has been instructed to confirm the ground survey of the house by the work called the Swedish sounding test, but most of the survey remains only before the construction, and there is nothing that has been confirmed after the construction. Although there were difficulties such as time and cost, the present invention is mainly intended to produce an effect up to 2 meters deeper than the lower end of the foundation, so that soil improvement can be reliably achieved at low cost. In addition, materials during field work can be presented to the architect in real time by scanning the image data via the Internet and the contents of the construction can be confirmed without attending the site.

It is sectional drawing of the solid foundation by this invention construction method.

  As described above, the present invention plans a groove of a predetermined width in the site area surface to be constructed, and runs a vibrator and a soil compacting machine for the groove before the construction of the housing foundation construction part, In line with the method stipulated by Notification No. 1113 on July 2, 2001, which was announced based on Article 93 of the Building Standards Law Enforcement Ordinance with the effect of rolling compaction 2 meters deeper than the bottom of the foundation, Conduct a ground survey to determine the allowable stress level of the ground and the allowable bearing capacity of the foundation. Based on the results, confirm the allowable stress level of the ground and the allowable bearing capacity of the soil improvement foundation (that is, the stabilizer). By filling and compacting the soil that is mixed with on-site soil and cement-solidifying material into the recessed part due to the rolling pressure of the groove on the upper part of the improved foundation, the subsidence of 1 kilonewton is less than 2 meters deep from the bottom of the foundation. Strengthened to avoid Building quality improvement foundation (the stable material).

  At this time, the Swedish sounding method is applied to several parts of the foundation construction before the work that gives rolling pressure and vibration, and the test results of the Swedish sounding method at the same place as before the work are verified after the completion of the work. After confirming that it meets the above-mentioned ministerial ordinance, the ground improvement foundation part and the solid foundation by the stable ground are integrated by placing reinforcing bars on the part that becomes the solid foundation on the upper surface of the stable ground. The soil surrounded by the soil improvement foundation or the ground improvement part (stabilizer) and the solid foundation becomes a rigid body, and can prevent uneven settlement of the building.

  Next, the present invention will be specifically described with reference to the drawings. FIG. 1 is a cross-sectional view of one embodiment of the present invention.

  As shown in the figure, a groove with a predetermined width is planned in the area of the site area to be built, and a vibrator and a soil compaction machine are driven for the groove (width 50 to 60 cm) before the construction of the housing foundation construction part. It was regulated by Notification No. 1113 on July 2, 2001 that was promulgated based on Article 93 of the Building Standards Law Enforcement Ordinance with the effect of compacting the soil of the groove to a depth of 2 meters or more at the bottom of the foundation In order to determine the allowable stress level of the ground and the allowable bearing capacity of the foundation, the allowable stress level of the ground and the allowable support of the soil improvement foundation (ie, the stabilizer) 11 are based on the results. Check the power. At this time, the Swedish sounding method is applied to several parts of the foundation construction before the work that gives rolling pressure and vibration, and the test results of the Swedish sounding method at the same place as before the work are verified after the completion of the work. After confirming that it conforms to the ministerial ordinance, the ground improvement foundation and the solid foundation are integrated by placing reinforcing bars and placing concrete on the solid foundation on the upper surface of the stable ground.

  The recessed part h that has been lowered from the standard ground by vibration rolling pressure when checking the strength of the ground by the Swedish sounding before construction is filled with soil material mixed with on-site soil and cement solidified material and rolled with rammer etc. The solid foundation 10 and the foundation rising 12 can be integrated after the improved soil stabilizer 11 having soil strength. The solid foundation 10 and the foundation rising 12 can be integrated by placing a cloth foundation (not shown) on or near the ground improvement foundation (stabilizing material 11).

As shown in FIG. 1, the load P from the roof, the final installation surface (determining the position of soil improvement according to the conditions of the initial installation surface) S, the bottom area Am ^{2 of the} ground improvement or line improvement part, the same depth H ( Determined by survey), the inner area surrounded by the ground improvement part (A), and the weight of the entire building is Wton, the ground reaction force of the bottom area of the ground improvement part, σc is W / σc (ton / m ² ) It becomes. The soil quality will be improved so that it will be less than the expected soil strength from the results of the Swedish sounding method (the solid foundation exists as a surplus). In addition, illustration of a solid basic bar arrangement etc. is abbreviate | omitted in the figure.

  As mentioned above, after confirming the strength of the ground by Swedish sounding before construction, a groove (width 50 to 60 cm) is planned in advance in the ground, and a machine with the effect of vibration and rolling pressure is operated in the groove. The ground will be strengthened so that it will not fall below 1 kilonewton self-sink 2 meters deeper than the bottom of the foundation specified in the Ministerial Ordinance. Filled with the soil which mixed the soil of the foundation construction part and the cement solidified material in the recessed part h which was lowered from the standard ground by vibration and rolling pressure to make the GL height, and the soil part was compacted to give soil strength. A stabilizer is made, and a solid foundation reinforcement is placed on the top surface of the stabilizer, and concrete is cast and integrated.

As described above, assuming that the bottom area of the soil improvement part or the line improvement part is Am ² and the weight of the whole building is Wton, the ground reaction force σc of only the improved bottom area is σc = W / A (ton / m ² Therefore, from the result of the Swedish sounding test, the solid foundation part exists as a surplus by improving the soil so that it will be less than the assumed ground strength. After placing a solid foundation reinforcement on the upper surface of the soil quality improvement part (stabilizer) 11, placing a solid foundation 10 and forming a foundation rising portion 12, an upper structure is constructed as usual. The foundation rising portion 12 may be a normal formwork, and may be removed after the concrete is cast. However, a finishing material (not shown) with good adhesion to the concrete is directly placed on the outer periphery of the foundation rising portion. It is possible to omit the work of removing the formwork after hardening the concrete by using it as a frame and placing a discarded formwork inside and placing concrete for forming the foundation rising portion. In the figure, the symbol P is a load from the upper house, and H is the depth of the soil improvement part, which is determined by ground survey.

Table 1 shows Swedish sounding test results at a predetermined station position before the ground improvement [load W, half rotation speed Na, penetration depth D (m), penetration amount L (cm) and penetration situation, estimated column diagram, Load Wsw / kN, half rotation speed Nsw per 1 m penetration amount, converted N value, converted qu (kN / m ² )]. Table 2 shows test results after ground reforming, and shows that the converted N value and converted qu after ground reforming at a penetration depth of 1 m or more are greatly improved.

  In FIG. 1, the load P transmitted from the shed is transmitted to the tip of the ground improvement due to the knots formed in the ground, and some subsidence occurs. At that time, the generated movement of the soil enters the inside (A) of the ground improvement and is compressed, and since the surroundings are restrained, the ground becomes hard. Therefore, the horizontal position of the tip of the improved ground becomes the installation surface in six months to one year after construction. That is, although it becomes the form equivalent to what improved the ground over the whole, rather than the case where the whole is improved by the same depth, the familiarity of the ground becomes better and it becomes an economically superior foundation construction method.

In addition, when using together a stabilizer and a field placement pile (illustration omitted), a required number of field placement piles is constructed in the solid foundation construction area which is a soft ground. In this case as well, a soil improvement part (stabilizer) having a soil strength similar to that described above is prepared by planning a continuous soil improvement part groove surrounding the soil reinforced by the site-placed pile. After the solid foundation reinforcement is fixed on the top surface of the stabilizer, concrete is placed on the stabilizer, the top of the pile placed on the spot, and the solid foundation part to be integrated. In-situ piles are constructed by mixing and agitating soil cement (for example, 300 kg / m ³ ) in excavated soil in a drilled pile hole and filling the slurry with water added thereto. Since this site-casting pile has the purpose of not a support pile but a stabilizing material, the solid foundation concrete is arranged by arranging the upper surface of the stabilizer with the improved soil with soil strength and toughness and the top of the site-casting pile. To complete the construction of the foundation.

  As described above, according to the present invention, since the reinforcement is arranged on the top of the stabilizer formed by improving the soil quality on the foundation of the building and integrated with the solid foundation, the stabilizer is surrounded by the solid foundation. The soil becomes a rigid body. Moreover, when using a stabilizer and an in-situ pile in combination, it becomes remarkably stronger than the surrounding soil, and it is possible to reliably prevent uneven settlement of the building.

10 Solid foundation 11 Ground improvement part (stabilizer)
12 Foundation rising part S Final ground surface H Depth of reinforced ground h Recessed part

Claims (3)

A solid foundation method for building a solid foundation for buildings on the ground,
A first test step in which a Swedish sounding test is performed as a test for confirming the allowable stress level of the ground at several places where the building foundation (10, 12) of the building is constructed;
In the place where the housing foundation (10, 12) is constructed, the recessed portion (h) is formed so as to include the place where the test was performed in the first test step by performing a construction that applies rolling pressure and vibration. And forming a reinforced ground forming step for strengthening the ground below the recessed portion (h),
A second test step for performing a Swedish sounding test in the same manner as the first test step at the location where the test was performed in the first test step, with respect to the ground reinforced in the reinforced ground creation step,
Filling the indented portion (h) with a cement mixture obtained by mixing on-site soil and cement solidifying material;
A solid foundation construction method including a step of constructing a solid foundation integrated with the cement mixture by placing concrete on top of the cement mixture. The solid foundation construction method according to claim 1, further comprising a step of placing a fabric foundation on or near the cement mixture. The solid foundation construction method according to claim 1, further comprising a step of giving soil strength to the cement mixture by solidifying the cement mixture before the step of constructing the solid foundation.

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