JP2008145324A - Method of measuring earth pressure in original position ground - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for accurately measuring static earth pressure and active earth pressure in an original position ground used in design of an underground building frame external wall of a newly constructed structure or an earth retaining wall or the like by using an existing underground building frame outer wall when a structure is newly constructed by dismantling the existing structure having an underground building frame. <P>SOLUTION: In the method for measuring the static earth pressure in the original position ground acting on the existing structure having the underground building frame, a hydraulic jack 5a is installed on a slab 2 of the underground building frame 1, and the load of the hydraulic jack 5a is increased to bear axial force acting on the slab by the earth pressure on the hydraulic jack 5a. The slab 3a of a part of an interval installing hydraulic jack frames 6a, 6a in a state where horizontal deformation is not generated in the underground building frame external wall is dismantled, and the static earth pressure is obtained by measuring load acting on the hydraulic jack 5a. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  In the present invention, when an existing structure having an underground structure is dismantled and a new structure is constructed, the static earth pressure of the in-situ ground used for designing the outer wall of the new structure, the retaining wall, etc. It belongs to the technical field of the method of measuring the main earth pressure accurately using the existing outer wall of the underground structure.

In general, when constructing the underground structure of the structure, measure the main earth pressure so that the outer wall or retaining wall of the built underground structure will not collapse due to the main earth pressure in the in-situ ground. Based on the design, the wall thickness of the outer wall of the underground frame and the retaining wall and the number of reinforcing materials such as H steel are designed. Incidentally, the main earth pressure is the maximum earth pressure at which the ground acts on the outer wall of the underground frame, the retaining wall, etc., and horizontally moves the underground frame and the retaining wall.
For example, in Patent Documents 1 to 3 listed below, hydraulic jacks are installed via H steel between the retaining walls installed when constructing the underground structure of a new structure. And the technique of measuring the main earth pressure which acts on the earth retaining wall with this hydraulic jack is indicated.

JP-A-5-156634 JP 2000-212962 A JP-A-9-178517

The earth pressure measuring methods described in Patent Documents 1 to 3 are effective techniques for measuring the main earth pressure acting on the earth retaining wall that is installed when constructing the underground frame of the new structure. In other words, it is not a technique to measure the static earth pressure and the main earth pressure of the in situ ground acting on the underground structure of the existing structure.
As a method of measuring the earth pressure of the in-situ ground acting on the underground structure of the existing structure, a method of measuring the earth pressure using, for example, a borehole is also considered. However, high measurement accuracy cannot be obtained, and implementation is difficult due to problems such as complicated measurement methods.
In general, the earth pressure at the original position varies depending on the deformation state of the ground and the outer wall of the underground frame, and it is known that passive earth pressure> static earth pressure> main earth pressure as shown in FIG. ing. Therefore, it is generally considered that the main earth pressure in the in-situ ground is between the static earth pressure and the main earth pressure because the ground is once loosened when the underground structure is constructed. However, when designing a new structure, there are no examples of earth pressure measurement in the design of the outer wall and earth retaining wall of the underground frame, and the underground wall and earth retaining wall etc. of the underground frame will not collapse due to changing earth pressure. A large static earth pressure (static earth pressure coefficient 0.5) is used in anticipation of safety.
However, the outer wall of the underground frame or the retaining wall designed using the static earth pressure described above is expensive and uneconomical because the wall thickness increases and the amount of reinforcing bars increases. In other words, if you can measure the exact static and active earth pressure on the in-situ ground acting on the outer wall and retaining wall of the underground structure, you can design and build a new outer wall and retaining wall based on the measurement results. Therefore, construction costs can be greatly reduced.

  The object of the present invention is to construct a new structure by dismantling an existing structure having an underground structure, and to construct a static structure on the in-situ ground used for the design of the outer structure of the new structure, retaining walls, etc. An object of the present invention is to provide a method for accurately measuring the pressure and the main earth pressure using the existing outer wall of the underground structure.

As a means for solving the problems of the prior art, the earth pressure measurement method in the in-situ ground according to the invention described in claim 1,
A method for measuring static earth pressure on an in-situ ground acting on an existing structure having an underground structure,
Installing a hydraulic jack 5a on the slab 2 of the underground housing 1;
Increasing the load of the hydraulic jack 5a and causing the hydraulic jack 5a to bear the axial force acting on the slab 2 by earth pressure;
The axial force acting on the slab 2 is borne by the hydraulic jack 5a, and the slab 3a is disassembled between the hydraulic jack mounts 6a and 6a in a state where horizontal displacement does not occur on the underground outer wall 4 and the hydraulic jack It is characterized in that a static earth pressure is obtained by measuring a load acting on 5a.

The invention described in claim 2 is the earth pressure measurement method in the in-situ ground described in claim 1,
When installing the hydraulic jack 5 a on the slab 2 of the underground skeleton 1, a measuring device 7 for measuring the displacement of the outer wall 4 of the underground skeleton 1 is installed in the indoor part S of the underground skeleton 1 or the outer wall 4 of the underground skeleton 1. An inclinometer 8 for measuring the displacement of the basement is installed in the cored underground substructure S, and the horizontal displacement of the basement outer wall 4 is measured by the measuring instrument 7 or the inclinometer 8 while the basement outer wall 4 is The load of the hydraulic jack 5a is increased to the limit not horizontally displaced, and the axial force acting on the slab 2a due to earth pressure is borne on the hydraulic jack 5a.

Invention of Claim 3 is the earth pressure measuring method in the in-situ ground described in Claim 1 or 2,
After obtaining the static earth pressure with the hydraulic jack 5a installed on the slab 2, the load of the hydraulic jack 5a is lowered to horizontally displace the underground outer wall 4 and the jack load when the hydraulic jack load settles to a constant value. The main earth pressure is obtained by measuring

  The earth pressure measurement method in the in-situ ground of the present invention can accurately measure the main earth pressure and the static earth pressure in the in-situ ground using the underground structure 1 of the existing structure. The newly constructed underground frame outer wall 4 designed and constructed using this can reduce the wall thickness compared to the conventional underground frame outer wall constructed with safety in mind, and can greatly reduce the amount of rebar, greatly increasing costs. Can be reduced. In addition, when building a retaining wall, etc., if designed using the measured main earth pressure, the wall thickness can be reduced compared to the conventional outer wall of the underground frame, and the H-shaped steel used as a reinforcing material can be reduced. This can greatly reduce the cost.

  A hydraulic jack 5 a is installed on the slab 2 of the underground housing 1. The load of the hydraulic jack 5a is increased, and the axial force acting on the slab 2 due to earth pressure is borne on the hydraulic jack 5a. The axial jack force acting on the slab 2 is borne by the hydraulic jack 5a, and the slab 2a between the hydraulic jack mounts 6a, 6a is disassembled in a state where no horizontal displacement is caused on the underground outer wall, and the hydraulic jack 5a is disassembled. Measure the load acting on the soil and obtain the static earth pressure.

Hereinafter, the present invention will be described based on the embodiments shown in FIGS.
The earth pressure measurement method in the in-situ ground of the present embodiment is an existing structure having an underground structure 1, dismantling the existing structure leaving only the underground structure 1, and using the remaining underground structure 1. This is a method of measuring the static earth pressure and the main earth pressure of the in-situ ground acting on the outer wall 4 of the underground frame 1.

  First, as shown in FIG. 1, before dismantling the remaining underground structure 1 of the existing structure, on the upper surface of the upper slab 2 of the underground structure 1 near the underground structure outer wall 4 at both ends. The hydraulic jack 5a provided with the mounts 6a and 6a is installed. A necessary number of the hydraulic jacks 5a are appropriately installed according to the magnitude of the axial force acting on the upper slab 2. And the light wave measuring machine 7 which measures the horizontal displacement of the outer wall 4 of the said underground skeleton 1 is installed in the indoor part S of the underground skeleton 1. Reference numeral 7a in FIG. 1 indicates the light wave target. As shown in FIG. 7, instead of the light wave measuring device 7, an inclinometer 8 for measuring the horizontal displacement of the outer wall 4 of the underground housing 1 may be installed in the cored underground housing S. Good (invention of claim 2).

  When the installation of the hydraulic jack 5a and the light wave measuring device 7 is completed, the behavior of the horizontal displacement of the underground outer wall 4 due to the static earth pressure of the original ground is measured by the light wave measuring device 7 installed in the room S of the underground housing 1. However, the load of the hydraulic jack 5a is increased, and the axial force acting on the upper slab 2 due to earth pressure is borne on the hydraulic jack 5a.

  Thereafter, as shown in FIG. 2, while the hydraulic jack 5a is installed in a state where the axial force acting on the upper slab 2 is borne by the hydraulic jack 5a and the horizontal displacement of the underground outer wall 4 is not generated. The upper slab 2 of the part 2a is disassembled using a concrete cutter or the like. When the upper slab 2a is dismantled, the horizontal displacement behavior of the underground skeleton outer wall 4 is measured by the light wave measuring machine 7 so that the underground skeleton outer wall 4 is not horizontally displaced by the dismantling of the upper slab 2a. The load of the hydraulic jack 5a is increased to the limit that the outer wall 4 of the casing is not displaced horizontally.

Next, as shown in FIG. 3, hydraulic jacks 5 b provided with pedestals 6 b and 6 b at both ends are installed on the upper surface of the lower slab 3 of the underground casing 1 and in the vicinity of the outer wall 4 of the underground casing. The necessary number of the lower hydraulic jacks 5b is also installed according to the magnitude of the axial force acting on the lower slab 3.
Thereafter, the horizontal displacement behavior of the underground outer wall 4 is measured by the measuring device 7, the load of the hydraulic jack 5b is increased, and the axial force acting on the lower slab 3 is loaded on the hydraulic jack 5b by earth pressure. Let

Next, as shown in FIG. 4, the axial force acting on the lower slab 3 is borne by the lower hydraulic jack 5 b, and no horizontal displacement occurs on the underground outer wall 4, so that the hydraulic jack of the lower slab 3 is not generated. The lower slab 3 of the portion 3a between the frames 6b and 6b is disassembled with a concrete cutter or the like. When the lower slab 3 is dismantled, the horizontal displacement behavior of the underground skeleton outer wall 4 is measured by the light wave measuring instrument 7 so that the underground skeleton outer wall 4 is not horizontally displaced by dismantling the lower slab 3. The load on the upper and lower hydraulic jacks 5a and 5b is increased as long as the underground outer wall 4 is not horizontally displaced.
Finally, the load acting on the hydraulic jacks 5a, 5b installed on the upper slab 2 and the lower slab 3 is measured using a pressure gauge, a load meter, etc., and the earth pressure distribution is triangular or trapezoidal depending on the ground conditions. Assuming the distribution, the static earth pressure is obtained.

  After obtaining the static earth pressure with the hydraulic jacks 5a and 5b installed on the upper slab 2 and the lower slab 3, as shown in FIG. 5, the hydraulic jacks 5a and 5b installed on the upper slab 2 and the lower slab 3 are used. The outer wall 4 of the underground skeleton is horizontally displaced by reducing the load of each. The loads acting on the hydraulic jacks 5a and 5b of the upper slab 2 and the lower slab 3 when the loads of the hydraulic jacks 5a and 5b of the upper slab 2 and the lower slab 3 are respectively settled to a constant value are expressed as pressure gauges and load gauges. Etc. to determine the main earth pressure (the invention according to claim 3).

  Thereafter, all the remaining underground structures 1 are dismantled, and a new structure having an underground outer wall is constructed using the measured static earth pressure. That is, the new underground outer wall 4 designed and constructed using the static earth pressure measured by the earth pressure measurement method of the present embodiment is thinner than the conventional underground outer wall constructed in anticipation of safety. And the amount of reinforcing bars can be greatly reduced, and the cost can be greatly reduced.

  In addition, when building a retaining wall, etc., if designed using the measured main earth pressure, the wall thickness can be reduced compared to the conventional outer wall of the underground frame, and the H-shaped steel used as a reinforcing material can be reduced. This can greatly reduce the cost. In addition, the existing underground skeleton outer wall 4 can also be used as a retaining wall when a new underground skeleton is constructed.

  In addition, as shown in FIG. 6, the earth pressure measuring method of a present Example measures a stationary earth pressure and a main earth pressure accurately by repeating the said procedure, even in the case of an underground frame with many stories. be able to.

  FIG. 8 shows a method for measuring the earth pressure at a depth half the depth of the underground outer wall 4 from the ground. The specific configuration is substantially the same as the earth pressure measurement method of the first embodiment described above, but is different in that the hydraulic jack 5a is installed only on the upper surface of the upper slab 2 of the underground frame 1.

  The present invention has been described based on the embodiments. However, the present invention is not limited to the illustrated embodiments. As long as it does not deviate from the gist and technical idea of the present invention, it will be mentioned here that various embodiments can be realized according to modifications and applications of those skilled in the art.

It is sectional drawing which shows the state which installed the hydraulic jack, the mount, and the measuring machine in the upper stage slab. It is sectional drawing which shows the state which disassembled the upper stage slab. It is sectional drawing which shows the state which installed the hydraulic jack and the mount frame in the lower slab. It is sectional drawing which shows the state which disassembled the lower slab. It is sectional drawing which shows the state which reduced the load of the upper side and the lower hydraulic jack. It is sectional drawing which shows the earth pressure measuring method in case there are many levels of underground structures. It is explanatory drawing which shows the earth pressure measuring method of Example 2. FIG. It is sectional drawing which shows the earth pressure measuring method of Example 3. It is explanatory drawing which shows the magnitude | size of the earth pressure which acts on the outer wall of an underground skeleton.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Underground frame 2, 3 Slab 4 Underground frame outer wall 5a, 5b Hydraulic jack 6a, 6b Hydraulic jack mount 7 Measuring machine 8 Inclinometer

Claims (3)

A method for measuring static earth pressure on an in-situ ground acting on an existing structure having an underground structure,
Installing a hydraulic jack on the slab of the underground structure;
Increasing the load on the hydraulic jack and causing the hydraulic jack to bear the axial force acting on the slab by earth pressure,
The axial force acting on the slab is borne by the hydraulic jack, the portion of the slab between the installation of the hydraulic jack stand is disassembled without causing horizontal displacement on the outer wall of the underground enclosure, and the load acting on the hydraulic jack is measured. A method for measuring earth pressure on an in-situ ground characterized by obtaining static earth pressure.   When installing a hydraulic jack on the underground slab, install a measuring instrument to measure the displacement of the outer wall of the underground enclosure, or install an inclinometer to measure the displacement of the outer wall of the underground enclosure. Installed inside the underground structure, while measuring the horizontal displacement behavior of the outer wall of the underground structure with the measuring device or inclinometer, increasing the load of the hydraulic jack to the extent that the outer wall of the underground structure is not horizontally displaced, 2. The method for measuring earth pressure on an in-situ ground according to claim 1, wherein an axial force acting on the slab is applied to the hydraulic jack.   After obtaining the static earth pressure with a hydraulic jack installed on the slab, reduce the load of the hydraulic jack to horizontally displace the outer wall of the underground building, and measure the jack load when the hydraulic jack load settles to a constant value. 3. A method for measuring earth pressure on an in-situ ground according to claim 1 or 2, wherein main earth pressure is obtained.

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