JP6259591B2 - Structure for preventing uneven settlement of structures - Google Patents

Description

  The present invention relates to a structure for countermeasures against uneven settlement of structures that can reduce uneven settlement without depending on the basic form of the structure.

  Regardless of the foundation type (direct foundation, pile foundation, combined use foundation), subsidence occurs due to the vertical load of the structure on the ground supporting the structure. The subsidence is affected by the weight of the structure, its shape, the non-uniform characteristics of the ground, etc., so that the subsidence varies from place to place directly under the structure. This phenomenon is called uneven settlement. Since the foundation subsidence gives additional stress to the structure, the foundation structure that can withstand the stress generated in the foundation beam (usually by selecting the foundation type that the amount of subsidence falls below the allowable value) The foundation beam is being designed.

  On the other hand, if the amount of uneven settlement can be reduced, it will be possible to change the pile foundation to a direct foundation, or to reduce the beam back of the foundation beam, making it possible to realize a rational and economical foundation. In recent years, foundation structures that can reduce the amount of uneven settlement have been developed (see, for example, Patent Document 1).

  The foundation structure of Patent Document 1 is a subsidence amplifying material (for example, styrofoam) having a Young's modulus smaller than the Young's modulus of the ground between the foundation plate and the ground at a position where the subsidence amount is relatively small. In addition, the amount of subsidence at the base of the part was increased, and the difference in the amount of subsidence from the part with a large amount of subsidence was reduced.

Japanese Patent No. 3760618

  However, in the foundation structure of Patent Document 1, since the settlement amplifying material is composed of a sheet material or a block material made of foamed polystyrene, styrofoam, or the like, it can only be applied directly to the foundation. In the subsidence amplifying material of Patent Document 1, it is only possible to select a material having a different foaming rate when setting the Young's modulus, and since there are few options for Young's modulus that can be selected, a subsidence amplifying material suitable for structural calculation can be obtained. There was no problem. Further, in the case of a direct foundation, it is difficult to set the laying range of the settlement amplifying material strictly, and it is necessary to lay in a wide range.

  From such a point of view, the present invention is applicable to pile foundations other than direct foundations, and an object thereof is to provide a structure for countermeasures against uneven settlement of structures that can be adapted to structural calculations.

The invention according to claim 1 for solving the above-mentioned problem is a structure for countermeasures against uneven settlement that transmits the load of a structure to the ground through a foundation, wherein the foundation includes a plurality of footing foundations connected by foundation beams, A subsidence amount control means is provided between the footing foundations at the outer four corners and the pile heads of the piles, or inside the footing foundations at the outer four corners of the building, and the subsidence amount control means is provided only at the outer four corners of the building. provided on, each sinking amount control means includes a telescoping jack to stretch in the longitudinal direction, and a regulator for adjusting the hydraulic pressure of the telescopic jacks, based on the subsidence of the footing foundation for building inner substantially adjusted to the same time the telescopic jack constituting the subsidence control means installed in a building outward through said base beam contracts individually the building interior, and the building outer A differential settlement measures structure of the structure, characterized in that to substantially uniformly sinking the upper surface of the footing foundation.

  The set hydraulic pressure value may be a pressure corresponding to the load of the structure borne by the extension jack. When the other portion having a relatively large subsidence sinks and the burden load of the telescopic jack increases, the telescopic jack contracts, and the difference in the subsidence amount from the other part can be reduced. In addition, according to such a configuration, it is possible to install on the pile by using an extension jack as the subsidence amount control means, and it is possible to arbitrarily set the set hydraulic pressure value of the extension jack. A suitable settlement amount control device can be obtained.

  According to such a configuration, the spring member receives the load of the structure at the time of completion and completion and is contracted to a predetermined height. When the burden load on the member is increased, the spring member is further contracted, so that the difference in the amount of settlement with other portions can be reduced. In addition, since a spring member is used as a settlement amount control means, it can be installed on a pile, and a spring having an arbitrary spring constant can be arbitrarily selected, so that a settlement amount control device suitable for structural calculation can be obtained. .

The invention which concerns on Claim 2 WHEREIN: In the dissimilarity settlement countermeasure structure which transmits the load of the structure provided with a high-rise part and a low-rise part to the ground via a foundation, it is between the foundation of the said low-rise part, and the pile head of a pile. A subsidence amount control means, and the subsidence amount control means is a telescopic jack that expands and contracts in the vertical direction or a spring member that expands and contracts in the vertical direction , and the low layer part is pulled downward by the vertical load of the high layer part. This is a structure for countermeasures against uneven settlement of structures characterized by being configured to shrink.

  ADVANTAGE OF THE INVENTION According to this invention, while being applicable also to pile foundations etc. other than a direct foundation, the structure for the non-uniform settlement of a structure which can be adapted to structural calculation can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS It is the figure which showed the structure to which the dissimilarity settlement countermeasure structure which concerns on 1st embodiment of this invention is applied, Comprising: (a) is sectional drawing, (b) is a top view of a foundation. It is the schematic sectional drawing which showed the subsidence amount control means of the nonuniform subsidence countermeasure structure which concerns on 1st embodiment of this invention. It is the schematic sectional drawing which showed the modification of the installation structure of a settlement amount control means. It is sectional drawing which showed the settlement distribution by the equal distribution load on an elastic ground. It is sectional drawing which showed the settlement distribution by various foundation structures, (a) is a figure when a footing foundation (without a foundation beam) is used, (b) is a figure when a footing foundation (with a foundation beam) is used. , (C) is the figure before subsidence when the structure for countermeasures for non-settlement is applied to the footing foundation (with foundation beam), (d) is the figure after settlement when the structure for countermeasures for non-settlement is applied to the footing foundation (with foundation beam) FIG. It is the schematic sectional drawing which showed the subsidence amount control means of the nonuniform subsidence countermeasure structure which concerns on 2nd embodiment of this invention. It is sectional drawing which showed the case where the non-settlement countermeasure structure is applied to the structure on a different foundation ground. It is sectional drawing which showed the case where the non-uniform settlement countermeasure structure is applied to the structure of a different shape.

  As shown in FIG. 1, the dissimilarity settlement countermeasure structure 1 according to the first embodiment of the present invention transmits the load of the structure 2 to the ground 4 via the foundation 3. A settlement amount control means 10 is provided between the foundation 3 and the pile head of the pile 5. The foundation 3 of the present embodiment includes a plurality of footing foundations 3a provided at predetermined intervals, and a foundation beam 3b that connects adjacent footing foundations 3a. The footing foundation 3a is schematically shown with a rectangular cross section. The pile 5 is a support pile and extends to the support ground 4b below the surface layer ground 4a and is supported by the support ground 4b (see FIG. 1A).

  The subsidence amount control means 10 acts according to the non-uniform subsidence amount (specific operation will be described later). The settlement amount control means 10 is provided in the base 3 at a position where the settlement amount is relatively small. In this embodiment, it is provided in the lower part of the footing foundation 3a provided in the four corners of the foundation 3 (refer (b) of FIG. 1).

  As shown in FIG. 2, the settlement amount control means 10 includes an extendable jack 11 and a regulator 17. The telescopic jack 11 extends in the vertical direction, and expands and contracts in the vertical direction. The telescopic jack 11 is composed of, for example, a hydraulic cylinder, and includes a cylinder 12 and a piston 13 that moves in the cylinder 12 in the axial direction. The pressure chamber 14 defined by the inner wall of the cylinder 12 and the piston 13 is filled with hydraulic oil. The pressure chamber 14 is connected to a flow path 16 that leads to a storage tank 15 in which hydraulic oil is stored. The telescopic jack 11 is not limited to a hydraulic jack, and the fluid filled in the pressure chamber 14 may be other than hydraulic oil.

  The regulator 17 is a valve that adjusts the hydraulic pressure in the pressure chamber 14 of the telescopic jack 11, and opens when the hydraulic pressure in the pressure chamber 14 exceeds a set hydraulic pressure value. When the regulator 17 is opened, the hydraulic oil in the pressure chamber 14 is released to the storage tank 15 and the telescopic jack 11 is contracted. The set hydraulic pressure value is set to a pressure generated by a load corresponding to the column axial force provided on the extension jack 11 (a pressure corresponding to the load of the structure 2 borne by the extension jack 11). The regulator 17 is composed of, for example, an electromagnetic valve, and is opened by receiving a signal from a pressure sensor (not shown) that measures the fluid pressure in the pressure chamber 14 (a signal when the fluid pressure exceeds a set fluid pressure value). . In addition, the structure which opens the regulator 17 is not limited to this, The administrator who looked at the signal from a pressure sensor (not shown) may make it open manually.

  In FIG. 2, the settlement amount control means 10 is disposed between the lower end surface of the footing foundation 3 a and the pile head of the pile 5, but is not limited thereto. For example, as shown in FIG. 3, the cylinder 12 portion of the telescopic jack 11 may be embedded in the footing foundation 3a. If it does in this way, the installation space of subsidence amount control means 10 can be omitted, and the height of foundation 3 can be made low.

  Next, the operation effect of the dissimilarity settlement countermeasure structure 1 according to the first embodiment and the operation of the settlement amount control means 10 will be described in comparison with the mechanism in which the dissimilar settlement occurs.

As shown in FIG. 4, when an evenly distributed load acts on the ground 4 (support ground 4b) having a certain Young's modulus, the amount of settlement near the center of the load (the center of the building) increases, and the amount of settlement decreases toward the end. Therefore, the difference in relative subsidence occurs, resulting in non-uniform subsidence. If this is made to correspond to the foundation 3 of the structure 2, it will become as shown to (a) and (b) of FIG. (A) of FIG. 5 has shown the case where an independent foundation is used, and the footing foundation 3a inside a building and the footing foundation 3a outside a building are not connected. In this case, the footing foundation 3a on the inside of the building is subjected to more load than the footing foundation 3a on the outside of the building. Therefore, the amount of settlement of the footing foundation 3a on the inside of the building is the amount of settlement of the footing foundation 3a on the outside of the building. And a relative difference in subsidence amount (dissimilar subsidence amount) δ ₀ occurs.

In FIG. 5B, the footing foundation 3a inside the building and the footing foundation 3a outside the building are connected by the foundation beam 3b. In this case, a part of the vertical load of the footing foundation 3a on the inside of the building is transmitted to the footing foundation 3a on the outside of the building through the foundation beam 3b, so that the vertical load distribution received by the ground 4 changes (the inner load is changed). Therefore, the amount of dissimilar settlement δ ₁ becomes smaller than δ ₀ . Thus, the presence of the foundation beam 3b reduces the amount of uneven settlement of the foundation 3, but the foundation beam 3b generates a cross-sectional force (shearing force and bending moment) associated with the uneven settlement. In a typical design, but the differential settlement amount [delta] ₀ is carrying out the design of the foundation beam 3b to be equal to or less than the allowable value, when the design is difficult, from the spread foundation to reduce the subsidence to pile foundation Since it was necessary to select a change or an increase in the diameter or length of the pile foundation, the construction cost was increased.

  On the other hand, according to the non-uniform settlement countermeasure structure 1 according to the first embodiment (see (c) of FIG. 5), the footing of another position (inside the building) of the foundation 3 where the amount of settlement is relatively large. When the foundation 3a sinks, shear force is transmitted to the footing foundation 3a outside the building (four corners) by the foundation beam 3b, and the vertical load acting on the footing foundation 3a outside the building (four corners) increases. Pressure higher than the set hydraulic pressure is applied. At this time, the regulator 17 is actuated (opened) to release the working oil, so that the telescopic jack 11 is contracted. As shown in FIG. 5 (d), the footing foundation 3a on the outside of the building becomes the footing on the inside of the building. It sinks to the same depth as the foundation 3a. As a result, the shearing force is not transmitted from the foundation beam 3b to the footing foundation 3a outside the building, so that the hydraulic pressure in the pressure chamber 14 returns to the set hydraulic pressure value and the regulator 17 is closed. In the present embodiment, the regulator 17 is constituted by an electromagnetic valve, and the valve is opened and closed in conjunction with the increase and decrease of the hydraulic pressure in the pressure chamber 14, so that the above operation is repeated finely, and the outside of the building (four corners) The footing foundation 3a sinks substantially simultaneously with the sinking of the footing foundation 3a inside the building, and the hydraulic pressure in the pressure chamber 14 is maintained at a constant value (set hydraulic pressure value). That is, the regulator 17 is opened and the telescopic jack 11 is shortened so that the shearing force generated in the foundation beam 3b due to the settlement of the footing foundation 3a inside the building is eliminated, so that the footing foundation 3a and the building inside the building are shrunk. The difference in the amount of subsidence relative to the footing foundation 3a at the outer end (dissimilar subsidence) can be eliminated without limit (δ≈0). When the regulator 17 is manually opened, the unsettled settlement occurs until the regulator 17 is opened, and the unsettled amount can be eliminated by opening the regulator 17. If the time interval for performing the valve opening operation of the regulator 17 is shortened, the difference in the relative subsidence amount (dissimilar subsidence amount) between the footing foundation 3a inside the building and the footing foundation 3a outside the building is eliminated as much as possible (δ ≒ 0).

  As described above, according to the dissimilarity settlement countermeasure structure 1, the occurrence of dissimilar settlement can be suppressed. Furthermore, since the shear force generated in the foundation beam 3b can be eliminated as much as possible, the beam of the foundation beam 3b can be reduced, and the amount of beam main reinforcement and the amount of concrete can be reduced. In addition, since it is not necessary to select a change from a direct foundation to a pile foundation or to increase the diameter or length of the pile foundation, an increase in construction cost can be prevented.

  In addition, since the settlement amount control means 10 is constituted by the telescopic jack 11, it can be installed between the footing foundation 3 a and the pile 5. Therefore, the non-uniform settlement countermeasure structure 1 is not limited to applicable foundation types, and can be applied to various foundation types such as a direct foundation, a pile foundation, and a pile foundation (pile raft foundation). . In particular, Patent Document 1 cannot be applied to a pile foundation type in which the weight of the structure 2 is concentrated on the pile 5. Moreover, since the set hydraulic pressure value of the telescopic jack 11 can be arbitrarily set appropriately according to the load condition of the building, a subsidence amount control device that individually eliminates the shearing force generated in the foundation beam 3b is manufactured individually. Obtained.

  In addition, if the groundwater level is high directly below the foundation structure of the structure having a basement, the building load may not be partially transmitted to the ground due to the effect of buoyancy (effective ground pressure becomes 0), In such a part, there is a possibility that the conventional settlement amplifier does not work effectively. In this way, when the groundwater level in the ground 4 is higher than the position of the foundation 3 of the structure 2, the settlement amount control means 10 is provided in a space that is blocked by the bottom of the foundation 3. The water shielded space is constituted by, for example, a basement or a water shield pit partitioned from the ground 4 side. In this way, when the settlement amount control means 10 is provided in the underground room or in the impermeable pit, even if the groundwater level below the structure 2 is high, it is not necessary to be affected by the buoyancy caused by the groundwater.

  Next, the non-uniform settlement countermeasure structure 1 according to the second embodiment of the present invention will be described. In the differential settlement countermeasure structure 1 according to the second embodiment, as shown in FIG. 6, the settlement amount control means 20 is configured by a spring member 21. The subsidence amount control means 20 is provided between the footing foundations 3 a provided at the four corners of the structure 2 and the pile heads of the pile 5, similarly to the subsidence amount control means 10 of the first embodiment. The spring member 21 is configured by a coil spring. The spring member 21 is disposed so as to expand and contract in the vertical direction. When the spring member 21 is installed on a base plate (not shown) laid on the ground 2, the spring member 21 sinks the structure 2 when the sinking amount at the upper end of the spring member 21 does not go through the spring member. It is preferable to have a longitudinal elastic modulus that becomes larger. More preferably, the spring member 21 may have a longitudinal elastic modulus smaller than the Young's modulus of the support ground 4b.

  Specifically, the upper end portion of the spring member 21 is fixed to the lower surface of the footing foundation 3 a, and the lower end portion of the spring member 21 is fixed to the upper end surface of the pile 5. When the structure 2 is completed and completed, the spring member 21 is subjected to a pressure (hereinafter referred to as “initial pressure”) generated by a load corresponding to the column axial force provided on the spring member 21, and has already contracted. This is a state (hereinafter referred to as “initial state”).

  According to such subsidence amount control means 20, when the footing foundation 3a on the inside of the building having a relatively large subsidence sinks, shear force is transmitted to the footing foundation 3a on the outside (four corners) of the building by the foundation beam 3b. A pressure higher than the initial pressure (initial pressure) acts on the foundation 3a. As a result, the spring member 21 is further contracted from the initial state, so that the footing foundation 3a outside the building sinks. The spring member 21 is contracted so that the pressure increased from the initial pressure by the shearing force from the foundation beam 3b and the restoring force of the spring member 21 are balanced. As a result, the difference between the sinking amount of the footing foundation 3a inside the building and the sinking amount of the footing foundation 3a outside the building is reduced, so that uneven settlement can be suppressed. Here, if the spring member 21 has a longitudinal elastic modulus smaller than the Young's modulus of the supporting ground 4b, the amount of contraction of the spring member 21 can be increased. The difference from the sinking amount of the footing foundation 3a outside the building can be further reduced.

  Moreover, according to the uneven settlement countermeasure structure 1 which concerns on 2nd embodiment, since the settlement amount control means 20 is comprised by the spring member 21, it can install between the footing foundation 3a and the pile 5. FIG. Therefore, the applicable subsidence countermeasure structure 1 is not limited to applicable foundation types, and can be applied to various foundation types such as a direct foundation, a pile foundation, and a combination foundation thereof. In addition, since the value of the elastic coefficient can be arbitrarily set by replacing the spring member 21 with a desired spring constant, the spring member 21 is arbitrarily selected according to the ground conditions to be installed, and the optimal amount of settlement The control means 20 can be obtained separately.

  Furthermore, also in this embodiment, when the groundwater level in the ground 4 is higher than the position of the foundation 3 of the structure 2, the spring member 21 is water-impervious, such as a basement or a water-impervious pit, at the bottom of the foundation 3. It should be provided in the designated space. As described above, when the spring member 21 is provided in the basement or in the water-impervious pit, even if the groundwater level below the structure 2 is high, it is not necessary to be affected by the buoyancy due to the groundwater.

  As mentioned above, although the form for implementing this invention was demonstrated, this invention is not the meaning limited to the said embodiment, A design change is possible suitably in the range which does not deviate from the meaning of this invention. For example, in the above-described embodiment, the settlement amount control means 10 (20) is provided at the lower part of the footing foundation 3a provided at the four corners of the structure 2, but is not limited thereto. The position where the subsidence amount control means 10 (20) is provided is appropriately set according to the shape of the structure 2, the weight of the upper part, and the shape of the ground 4.

  For example, as shown in FIG. 7, when the support ground 4b is inclined below the structure 2 and a part of the structure 2 is supported by the pile 5, the vertical load of the structure 2 is Since the portion becomes larger and becomes smaller at the end portion, the settlement amount control means 10 may be installed at the lower portion of the foundation 3 outside the building. If the subsidence amount control means 10 is installed at such a position, the same operation and effect as in the above embodiment can be obtained.

  Moreover, as shown in FIG. 8, when the structure 2 is provided with the high layer part 2a and the low layer part 2b, the subsidence amount control means 10 should just be installed in the lower part of the foundation 3 of the low layer part 2b. If the subsidence amount control means 10 is installed at such a position, the lower layer part 2b is pulled downward by the vertical load of the high layer part 2a and the subsidence amount control means 10 is contracted. A working effect can be obtained.

  Furthermore, in the said embodiment, although the pile 5 is a support pile supported by the support ground 4b, this invention is applicable even if it is a friction pile.

DESCRIPTION OF SYMBOLS 1 Non-uniform settlement countermeasure structure 2 Structure 3 Foundation 3a Footing foundation 3b Foundation beam 4 Ground 5 Pile 10 Sinking amount control means 11 Telescopic jack 17 Regulator 20 Sinking amount control means 21 Spring member

Claims (2)

In the structure for countermeasures against uneven settlement that transmits the load of the structure to the ground via the foundation,
A plurality of footing foundations are connected by foundation beams, and a settlement amount control means is provided between the footing foundations at the outer corners of the building and the pile heads of the piles, or inside the footing foundations at the outer corners of the building. And
The subsidence amount control means is provided only at the four corners outside the building,
Each subsidence amount control means includes a telescopic jack that expands and contracts in the vertical direction and a regulator that adjusts the hydraulic pressure of the telescopic jack, and based on the subsidence amount of the footing foundation inside the building , the base beam is substantially simultaneously The telescopic jacks constituting the subsidence amount control means installed on the outside of the building are adjusted so as to shrink individually , and the upper surface of the footing foundation inside the building and the outside of the building is submerged substantially uniformly. Features a structure to prevent uneven settlement of structures. In the structure for countermeasures against uneven settlement that transmits the load of a structure with a high-rise part and a low-rise part to the ground via the foundation,
Between the foundation of the lower layer and the pile head of the pile, a settlement amount control means is provided,
The settlement amount control means is a telescopic jack that expands and contracts in the vertical direction, or a spring member that expands and contracts in the vertical direction ,
The structure for preventing uneven settlement of a structure, wherein the lower layer portion is configured to be pulled downward and contracted by a vertical load of the higher layer portion.

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