JP2006208338A - Method and device for determining ground property - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and device for determining ground properties that minimize time and labor when determining the effect to the ground of a structure, can determine an accurate ground state by the structure, and can visually determine a cause related to the problem investigation in execution of the structure or search for an execution method of a new structure. <P>SOLUTION: In the method for determining peripheral ground properties of a penetration structure, the temperature of the peripheral ground of the structure penetrated into the ground is measured, and the properties of the ground are determined based on the measured temperature distribution. The determining method comprises a ground forming step S1, a structure penetrating step S2, a ground cross section forming step S3, a temperature distribution measuring step S4, and a determining step S5. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a ground property determination method and a ground property determination device for investigating and determining the influence of a columnar, plate-shaped, or massive structure that presses or penetrates the ground on the ground.

  In general, various technologies for penetrating a plate-like structure such as a pile or a sheet pile such as a pile by hammering, vibration, rotation, etc. have been proposed in foundation work. As one of them, a rotary penetrating pile construction method is known in which a pile is penetrated into the ground while rotating. This rotary intrusion pile method can be constructed without vibration and noise, and since there is almost no discharged residual soil, no construction residual soil treatment is required. Furthermore, since no cement milk is used, soil contamination and groundwater contamination In recent years, it has been widely used because it meets the social needs due to the advantages such as the environment-friendly construction method.

  Since foundation works such as the pile method including the rotary penetrating pile method are performed by penetrating the structure into the ground, it is not only difficult to check the construction accuracy in the ground, but also the influence on the surroundings. It is difficult to investigate. For example, some rotary penetrating piles used in the rotary penetrating pile method have a spiral wing at the tip. In the rotary penetration pile method for piles with spiral wings, if the ground through which the spiral wings are compacted due to the penetration speed of the pile penetrating the ground, the properties of the ground compacted by the spiral wings are It may be disturbed.

  Therefore, conventionally, a ground measuring device for confirming the construction accuracy when a structure such as a pile penetrates the ground to be constructed has been proposed. For example, a penetrometer (Non-Patent Document 1), which is a device for measuring the hardness of the ground, is used, or a model experimental device (Non-patented) that can experimentally observe the situation of the surrounding ground of a structure in the ground Document 2) is known.

  A penetrometer measures the hardness of the ground by inserting a needle into the ground. This penetrometer measures the hardness at each measurement point by sequentially inserting the needle into the ground at a certain interval in the target area to be measured.

The model experiment device contains a large number of rod-shaped aluminum particles (1 to 3 mm in diameter) as a ground in a case with a transparent side surface, and is attached to the vertical movement device via a vertical movement device placed at the top of the case. The minutified foundation such as a pile is penetrated into a rod-like aluminum particle group that looks like the ground, or the foundation structure in the rod-like aluminum particle group is pulled out. And the model experiment device observes the ground condition when moving the foundation structure using the vertical movement device from the transparent side, and the position of the rod-like aluminum particles from the line marked on the transparent side in advance It is possible to conduct experiments such as determining whether or not to change, or measuring the supporting force of the foundation structure with respect to the ground, the pulling resistance force, and the like.
Maruto Manufacturing Co., Ltd. website (searched on January 26, 2005) <URL http://www.maruto-group.co.jp/soil/S44.htm> Maruto Manufacturing Co., Ltd. website (searched on January 26, 2005) <URL http://www.maruto-group.co.jp/education_maruto/AMS-822.htm>

However, in the conventional method for measuring the state of the outer peripheral ground of the foundation structure or the observation apparatus, a technical solution described below has been desired.
When measuring the hardness of the ground with a penetrometer, since the operation of inserting the needle into the ground is performed, the area around the ground where the needle is inserted is softened, making it impossible to measure a continuous area. In addition, since it is necessary to measure at a large number of points in the ground measurement area, time and labor are significantly required.

  On the other hand, since the model experimental device uses the rod-shaped aluminum particle group as the ground, it can reproduce only the rough ground state, and since the scale of the device is small, qualitative verification against the theory can be confirmed. It wasn't too much. And since this model experimental device forms the ground with rod-like aluminum particles, a measuring device such as a small penetrometer is also necessary to determine the hardness state on the outer peripheral surface of the foundation structure. It is had.

  In addition, when a construction problem occurs in the foundation structure at the site, a means for visually searching for the cause for investigating the problem with the construction situation or a construction method using a new foundation structure There has been a demand for a means by which the ground disturbance for searching for a hint can be visually determined.

  The present invention was devised in view of the above-mentioned problems, minimizes time and labor when determining the influence of the structure on the ground, and can accurately determine the state of the ground due to the structure. And the ground property determination method and ground property determination apparatus which can determine visually the cause which concerns on the construction problem investigation of a structure, or the search of the construction method by a new structure are provided.

  According to the present invention, it has been found that the temperature distribution state of the ground section and the ground hardness state of the ground section are correlated, and the temperature distribution is formed so as to correspond to the ground hardness distribution. It was made. In other words, for example, piles are penetrated into the ground (pressed against the ground), and the hardness of the ground distribution is measured by measuring the hardness of the ground at a number of measurement points with a measuring device such as a penetrometer in the cross section of the ground that has been penetrated (pressed ground). Check the condition. Then, the temperature distribution in the cross-section of the ground (pressed ground) through which the pile has penetrated under the same conditions is measured, and when compared with the hardness distribution examined in advance, the temperature distribution state is almost in accordance with the ground hardness state. The present invention has been achieved by finding that it is compatible. Therefore, in order to solve the above-described problems, a ground property determination method and a ground property determination device having the following configurations are provided. In addition, it is desired that the soil particles have a temperature distribution clearly appearing and reflect the properties of the ground in an easy-to-understand manner because of the property of measuring the temperature distribution of the ground cross section.

  The ground property determination method is a ground property determination method for measuring the temperature of the ground cross section in the ground pressed by the structure, and determining the property of the ground from the measured temperature distribution, and artificially in the bottomed formwork A ground formation step for forming and storing the ground, a structure pressing step for pressing the structure to be pressed against the ground from the opening side of the bottomed formwork against the ground according to preset construction conditions, and the structure A ground section forming step for opening at least a part of a side surface of the bottomed formwork of the ground pressed by an object to form a ground section of the ground pressed by the structure; and infrared heat for the ground section of the ground A temperature distribution measuring step of measuring the temperature distribution of the ground cross section within a preset time after pressing the structure against the ground by the image device; and the measured temperature of the ground cross section. Distribution from image showing, and the nature of the ground and include a determining step in Color of distribution and rate, a.

  In the ground property determination method as described above, first, the ground is artificially formed in the bottomed form to have a certain compaction hardness by the ground formation step, and preset by the structure pressing step. The ground is pressed by the structure under construction conditions, for example, a predetermined time with a predetermined pressing force. The structure at this time is, for example, a T-shaped leg, a columnar support, or the like. Next, the ground pressed by the structure in the ground section forming step is used to open a side surface of the bottomed formwork and remove (cut) a part of the ground to form a ground section. In addition, the cross-sectional position of the ground cross section may be appropriately changed depending on the purpose of determination, such as a vertical cross section at the center of the structure or other than that. When the ground section is formed, the temperature distribution of the ground section is measured by an infrared thermal imager (thermography) in the temperature distribution measuring step. Further, in the determination step, for example, since it is known that the hardness distribution and the temperature distribution of the ground section substantially correspond to each other, the structure of the ground is determined from the distribution state and ratio for each color in the measured temperature distribution image. The influence of the supporting force or the like due to the change in the hardness state is determined.

  The ground property determination method is a method for determining the peripheral ground property of the penetrating structure by measuring the temperature of the outer peripheral ground of the structure penetrating into the ground and determining the property of the ground from the measured temperature distribution. A ground formation step for artificially forming and storing the ground in the bottom mold, and a structure penetration step for penetrating the structure penetrating into the ground from the opening side of the bottomed mold according to preset construction conditions And opening at least a part of the side surface of the bottomed formwork of the ground into which the structure has penetrated, and removing a part of the ground so that at least a part of the structure in the ground or the periphery of the penetration part appears. A ground cross-section forming step for forming a ground cross-section, and an infrared thermal imager for the ground cross-section of the ground, within a preset time after the structure has penetrated the ground And measuring temperature distribution measurement step, the image showing the temperature distribution of the ground section was measured, and the properties of the ground and include a determining step in Color of distribution and rate, a.

  According to the ground property determination method described above, first, in the ground formation step, the ground is artificially formed in the bottomed formwork. The ground at this time is preferably compacted with a mallet, a weight or the like so as to be in a certain state. When the ground is formed, a structure corresponding to, for example, a pile, a sheet pile, an anchor, a caisson, or the like is inserted into the artificially formed ground under predetermined construction conditions. The construction conditions at this time are impact, press-fit, penetration speed including vibration, rotational speed, and the like.

  Moreover, penetration here is forcing a structure into the ground from the ground surface by combining any one or a plurality of means including striking, press-fitting, and vibration. In addition, the ground surface here includes not only the surface direction perpendicular to the vertical direction but also the surface direction in which a structure such as a side surface of a vertical hole or a slope of the ground penetrates in the field. Further, in the ground section forming step, a part of the ground is removed by cutting or the like to form a ground section. The ground cross section at this time may be any cross section such as a vertical cross section, a horizontal cross section, an inclined cross section, or a vertical cross section adjacent to the structure at a position where a part of the structure in the ground is exposed. Absent. Next, in the temperature distribution measurement step, the temperature distribution of the ground cross section is measured by an infrared thermal imager. And it is known that the temperature distribution of the ground section in the measured image corresponds to, for example, the hardness distribution of the ground. For this reason, in the determination step, the distribution state and ratio by color in the image of the temperature distribution of the outer peripheral ground (ground cross section) of the structure appear as differences in hardness, density, etc. between the peripheral ground and the structure outer peripheral ground, for example. It is possible to determine the influence of property disturbance, support force, etc. on the ground of the structure.

Further, in the ground property determination method, in the ground formation step, the ground is a mixed soil in which silica sand and clay are mixed at a ratio of 9: 1 to 1: 9, and the mixed soil has a moisture content. It was formed by adding so as to have any ratio in the range of 3 to 30%.
In this way, silica sand and clay are mixed in a predetermined range to make a mixed soil, and water is added at a predetermined ratio to make the ground, so that the temperature distribution can be easily displayed by the infrared thermal imager. It becomes possible. The ratio of silica sand to clay is preferably in the range of 8 to 2 to 2 to 8, more preferably 3 to 7 to 7 to 3. And it is more preferable that the moisture content of the water at that time is either 5 to 20%.

The ground property determination method may be configured such that the ground cross section exposed in the ground cross section forming step is a cross section in which a half circumferential surface around the axis of the structure is exposed around the structure.
In this way, the cross section of the ground that exposes the half circumference surface of the structure, that is, the state of the outer peripheral ground in a wide field of view showing both sides that are symmetric from the center of the structure, is measured by an infrared thermal imaging device. Can be determined by obtaining

Further, in the ground property determination method, the structure is a pile in the structure penetration step, and the construction condition allows the pile to penetrate the ground at a preset penetration speed.
Thus, the structure used by the ground property determination method is a pile, and the property of the ground can be determined from the temperature distribution in the ground cross section when the pile penetrates at a predetermined speed.

Further, in the ground property determination method, the extraction operation step is performed between the structure penetration step and the ground cross-section formation step, in which the penetration structure is operated in a direction of being extracted from the ground with a preset force.
Thus, in the ground property determination method, once the structure that has penetrated the ground is pulled in the direction of pulling out from the ground by applying a force in the pulling operation step, the ground property with respect to the pulling force applied to the ground is also indicated by temperature distribution. be able to.

  The ground property judging device is a ground property judging device for judging the property of the outer peripheral ground of the structure penetrating into the ground or the property of the ground pressed against the ground by the structure based on the temperature distribution. A bottomed mold for storing the formed ground, a penetration mechanism for pressing or penetrating the structure into the ground in the bottomed mold according to preset construction conditions, and the structure by the penetration mechanism For a ground pressed by an object or a ground that has penetrated the structure, a part of the ground is removed to form a ground cross section in a state where a part of the side surface of the bottomed formwork is released, or A removal mechanism for removing the ground so as to expose at least a part of the structure penetrating the ground to form a ground cross section; and a temperature distribution of the ground cross section formed by removing with the removal mechanism. Measured and said An infrared thermal image device to be displayed on the screen in different colors distribution and percentage of board section and configured to include a.

  The ground property judging device constructed in this way is a foundation that artificially forms the ground in the bottomed formwork and puts the ground into a fixed state, and supports the pile, pillar, sheet pile, caisson, etc. by the penetration mechanism. The structure is penetrated or pressed into the ground formed at a penetration speed or a rotational speed that is a preset construction condition. Furthermore, the ground property determination device opens a part of the side surface of the bottomed formwork and removes a predetermined portion of the ground where the structure has penetrated or pressed by a removal mechanism to form a ground cross section or penetrate into the ground. A ground section is formed so that a part of the structure is exposed. Then, when the ground cross section is formed, the ground property determination device measures the temperature distribution of the ground cross section with an infrared thermal imager (thermography), and determines the property of the ground from the image obtained by measuring the temperature distribution. . In addition, since it is known that the temperature distribution of the ground cross section in the measured image corresponds to, for example, the hardness distribution of the ground, the infrared thermal imaging device uses the measured image to determine the color in the image of the temperature distribution of the ground cross section. From other distribution states and ratios, for example, the influence of ground property disturbance, support force and the like on the ground structure can be determined.

The ground property determination method and the ground property determination device according to the present invention have the following excellent effects.
The ground property judgment method is to measure the temperature distribution of the ground section formed by cutting the ground that has penetrated or pressed a structure such as a pile, sheet pile, anchor, caisson, etc. And the ratio and the ground hardness distribution have been found to correlate, so without much time and effort, the ground condition due to the pressing of the structure, or the outer peripheral ground of the structure. It is possible to continuously determine the state. Therefore, in the ground property determination method, the influence of the structure on the ground such as the supporting force of the structure on the ground can be determined. In addition, since the ground property determination method can visually determine the property of the ground, for example, when a construction problem in a structure occurs on site, to investigate the problem with the construction status It is possible to visually determine the cause of the ground, or to visually determine the properties of the ground to search for hints when exploring the construction method with a new structure, and the effect of the structure on the ground It becomes.

  The ground property judgment method can measure the state of temperature distribution more clearly by forming the ground by adding a predetermined ratio of water to mixed soil with a predetermined ratio of silica sand and clay, so that the structure It is possible to more accurately determine the influence of the object on the ground and the properties of the outer peripheral ground of the structure.

  The ground property is determined by measuring the temperature distribution by forming the ground cross section so that the semi-circumferential surface around the axis of the structure is exposed, and measuring the temperature distribution is easy and easy to see and is continuous from the center of the structure. It is possible to determine the properties of the ground to be used.

  The ground property determination method determines the properties such as the disturbance of the outer peripheral ground of the pile by measuring the temperature distribution of the ground cross section when the structure is a pile and the penetration speed etc. which is the construction condition is preset. be able to.

  The ground property judgment method applies a force in the direction of pulling out the structure that has penetrated the ground from the ground with a predetermined force by the pulling operation step, and then measures the temperature distribution of the cross section of the ground, thereby grounding the structure when pulling out the structure. Properties in the ground such as pressure distribution and frictional resistance can be determined.

  The ground property judgment device determines the properties of the outer periphery of the structure, such as piles, sheet piles, anchors, caissons, etc., or the properties and effects of the ground when a structure such as a column presses the ground. It can be determined by measuring the distribution. In addition, since this ground property judgment device is in a state closer to the actual environment, it is suitable as a teaching material when learning earth pressure of a retaining wall, basic support theory, etc. as an experimental device. It is also suitable as an object design support means.

Hereinafter, typical configurations of a ground property determination method and a ground property determination device according to the present invention will be described with reference to the drawings. In addition, although demonstrated here using a pile as an example as a structure, it is not limited to this.
FIG. 1 is a schematic diagram illustrating an example of a ground property determination device used in the ground property determination method, and FIGS. 2A to 2E are schematic diagrams schematically illustrating each step in the ground property determination method.

  As shown in FIG. 1 and FIG. 2, the ground property determination device 10 is a rotating mechanism that holds a pile (structure) 12 above the installation position of the bottomed formwork 30 containing the ground B and rotates it at a predetermined speed. 13, an elevating mechanism 14 for raising and lowering the rotating mechanism 13, a removing mechanism 15 for removing a part of the ground B of the bottomed mold 30 to form a ground section BS, and the removing mechanism 15 and the elevating mechanism It mainly includes a frame 11 that supports the mechanism 14, the rotation mechanism 13, and the like at predetermined positions, and an infrared thermal imaging device (thermography) 20 disposed in front of the bottomed mold 30.

  The rotation mechanism 13 includes a load cell unit 13a for rotating the pile 12 to be held at a predetermined speed, a torque meter 13b for measuring the torque of the pile 12 rotated by the load cell unit 13a, and a torque value measured by the torque meter. The data logger 13c etc. which record etc. are provided.

  The elevating mechanism 14 supports the load cell unit 13a and the torque meter 13b, and elevates and lowers a support part 14a that elevates and lowers via the slide columns 14b and 14b, an elevating motor 14c that elevates and moves the elevating support part 14a at a predetermined speed, It has. In addition, the raising / lowering mechanism 14 raises / lowers the raising / lowering support part 14a by rotating at least one of the slide pillars 14b and 14b, and raises / lowers the sliding pillars 14b and 14b by moving the raising / lowering support part 14a by the slid. It doesn't matter if you do.

The removal mechanism 15 includes a ground removal plate 15a that abuts the ground B and removes (cuts) a part thereof, holding movement units 15b and 15b that detachably hold the ground removal plate 15a, and the holding movement unit 15b. Rotate at least one of the left and right guides 15c and 15c for engaging and moving the guide 15b and the guides 15c and 15c to move the holding and moving portions 15b and 15b to engage with the guides 15c and 15c up and down. A drive motor 15d to be moved is provided. When the drive motor 15d is provided on the left and right, the guides 15c and 15c are rotated in synchronization with each other.
Further, it is convenient that a plurality of holding positions are formed in the holding moving parts 15b and 15b so that the holding position of the ground removal plate 15a can be appropriately changed in the plane direction. Further, the ground removal plate 15 a is formed such that its center is curved along the curvature of the pile 12. The ground removal plate 15a is formed as a plate, but may be a string-like ground removal portion such as a wire.

The infrared thermal imaging device 20 is a device that detects infrared radiation energy emitted from an object, converts it into an apparent temperature, and displays an image of the temperature distribution. The infrared thermal measurement unit 21 and the infrared thermal measurement unit And a measurement display unit 22 for displaying an image of the state measured at 21.
This infrared thermal imager 20 can be viewed as surface temperature distribution with respect to the ground cross section, and can be displayed as visualization information. In addition, the temperature can be measured in a non-contact manner away from the object, and the temperature can be measured in real time. Can do.

  The ground property determination device 10 may be configured such that the pile 12 is detachably engaged at the position of the holding mechanism 17. Further, the installation position of the bottomed mold 30 may be a slide surface of the slide mechanism L2 that can move the bottomed mold 30 in a straight line. Furthermore, you may arrange | position the infrared thermal measurement part 21 of the infrared thermal imaging device 20 so that a movement on the slide rail L1 is possible. That is, after the pile 12 is inserted into the ground B of the bottomed formwork 30 and the ground section BS is formed, the pile 12 is disengaged from the position of the holding mechanism 17 and the bottomed formwork 30 is moved by the slide mechanism L2. Then, at the moved position, the ground rail BS is measured by the infrared thermal measurement unit 21 of the infrared thermal imaging device 20 that faces by moving the slide rail L1. In this way, by changing the measurement position to the penetration position of the pile 12, the next operation for measuring the bottomed mold 30 can be quickly performed.

Next, the ground property determination method will be described by appropriately using the ground property determination device according to the present invention. Of course, in the ground property determination method, it is not always necessary to use the ground property determination device shown in FIG.
As shown in FIG. 2, the ground property determination method SA includes a ground formation step S1, a structure penetration step S2, a ground cross-section formation step S3, a temperature distribution measurement step S4, and a determination step S5.

  As shown in FIG. 2A, the ground formation step S <b> 1 artificially forms the ground B in the bottomed mold 30. 2 (a) and 2 (c), here, the bottomed mold 30 is a cylindrical cylindrical body having a mold bottom 31 with an open top, and faces the side wall so that the side wall is split into two. The flange portions 32 and 32 are provided at the position of the side wall. Therefore, when the bottomed mold 30 moves the flanges 32 and 32 in a direction away from each other by removing the bolts and the like that fix the flanges 32 and 32 that are the side mold ends, the bottomed mold 30 is half of the side wall. Can be removed and the ground B housed inside can be exposed.

  Here, the ground B formed in the bottomed mold 30 is a mixed soil in which silica sand and clay are mixed at a predetermined ratio in a range of 1 to 9 to 9 to 1, and 3 to 30% of the mixed soil is formed. It is formed by adding so as to have a water content of water. The mixed soil preferably has a ratio of silica sand to clay of 2 to 8 to 8 to 2, more preferably 3 to 7 to 7 to 3, particularly 3 to 7 Most preferably in the range of 4 to 6.

And the ratio of the moisture content of the water added to the mixed soil is preferably 5 to 20%, more preferably 6 to 15%, and most preferably 7 to 10%.
Therefore, it is more preferable that the ground B has a water content of 7 to 10% in the range of 3 to 7 to 4 to 6 of silica sand and clay. In addition, when the temperature distribution to be described later is measured when the ratio of silica sand and clay is 3 to 7 and the water content of the added water is 7%, the state of the temperature distribution is displayed most clearly. .

  In the ground formation step S1, the ground B accommodated in the bottomed formwork 30 is compacted to a predetermined hardness by a weight or a mallet when it is formed. And if the ground B is artificially formed in the bottomed formwork 30, the pile (structure) 12 will be penetrated into the said ground B by predetermined construction conditions as structure penetration step S2.

  In this structure penetration step S2, as shown in FIG. 2 (b), in order to penetrate the pile 12 into the ground B under predetermined construction conditions, if the penetration speed, the rotational speed, or the hitting is necessary If the hammering mechanism or the press-fitting by vibration is performed, the pile 12 is penetrated into the ground B through the vibration mechanism.

For example, as shown in FIG. 1, as an example, the rotation mechanism 13 including the load cell unit 13a and the torque meter 13b and the elevating mechanism 14 as the press-fitting mechanism are adjusted so as to have a predetermined penetration speed at a predetermined rotation speed. And the pile 12 has penetrated the ground B artificially formed in the bottomed formwork 30.
Note that the pile 12 used here (see FIG. 10 (a)) has a drilling blade formed such that its tip becomes thinner from the body portion toward the tip, and the An example in which the body portion directly above has a spiral wing will be described.

  When the pile 12 penetrates into the ground B, as shown in FIG. 2 (c), in the ground cross section forming step S3, a part of the pile 12 or the ground around the penetration part penetrating the pile 12 is exposed. Remove the ground of the part. This ground section forming step S3 may be performed here by using the removal mechanism 15 in the ground property determination device 10 or by using a ground cutting tool or the like manually by the operator. In addition, when removing a part of ground B, the side wall of the bottomed formwork 30 is removed and a part of the ground B is removed.

  The position of the cross section of the ground cross section BS formed in the ground cross section forming step S3 is determined according to the purpose of measurement. For example, in the ground section forming step S3, when the ground section BS is formed by removing a part of the ground so that the half circumferential surface of the pile 12 is exposed, the properties of the left and right ground of the pile 12 are set to be the maximum area. it can.

In addition, as shown in FIG. 3A, for example, the ground cross-section BS to be formed has a fan-shaped column with a small width and a fan-shaped column having the same width so that a part of the pile 12 is exposed in the axial direction. Remove (cut out) to form the ground section BS ₁ or, as shown in FIG. 3 (b), the ground section BS ₂ around the penetrating portion of the penetrated pile 12 is exposed. It doesn't matter. Further, as shown in FIG. 3 (c), as the ground section BS _3, the slope of a predetermined angle from the vertical may be formed so as to be exposed when the pile 12 and the vertical. Furthermore, as shown in FIG. 3 (d), as ground section BS _4, it and so that the inclined surface and a vertical surface is formed at the same time, or, as shown in FIG. 3 (e), the side surface of the pile 12 The ground section BS ₅ may be formed so that both vertical sections of the exposed portion and the unexposed portion are exposed.

  When the ground section BS is formed, as shown in FIG. 2 (d), in the temperature distribution measurement step S4, the formed ground section BS is subjected to temperature distribution by the infrared thermal imager (thermography) 20, and the pile 12 penetrates. After that, the measurement is performed within a preset time. In this temperature distribution measurement step 4, measurement is performed within 15 minutes as a preset time after the pile 12 is penetrated. Since the pile 12 is penetrated and the ground section BS is formed and measured as quickly as possible, it is possible to clearly recognize the state of heat generated in contact with the soil grains when the pile 12 penetrates. It is desirable that it is within 10 minutes, more preferably within 5 minutes after penetration.

  Then, as shown in FIG. 2 (e), when the temperature distribution of the ground section BS is measured and displayed on the screen of the measurement display unit 22 in the determination step S5, the state of the ground section BS indicating the temperature distribution is displayed. Before the pile 12 is penetrated, it shows the properties of the ground due to the temperature distribution that changes in temperature compared to the almost uniform temperature distribution, so the pile in the underground of the pile 12 It can be determined as the properties of the outer peripheral ground. In the determination step S5, the present inventors have newly confirmed that the temperature distribution state and the hardness distribution state, which is the property of the ground, show a correlation.

  The correlation between the ground hardness distribution and the temperature distribution will be described with reference to FIGS. As shown in FIG. 4, a frame M having a mesh m having a predetermined width is arranged as a scale guide on the ground section BS where the temperature distribution is measured, and a handy type pocket penetrometer (at the intersection of the mesh m ( The hardness of the ground section BS is measured by a ground hardness measuring device P. Then, as shown in FIGS. 5A and 5B, when comparing the state of the image G1 of the temperature distribution and the state of the image Gs of the ground hardness distribution in the ground section BS, a certain hardness range and temperature It can be seen that the color range with the distribution appears in the same distribution state. That is, the image Gs obtained by measuring the ground section BS at a number of measurement points with the ground hardness measuring instrument P and the image G1 indicating the temperature distribution measured by the infrared thermal image device 20 are substantially in a distributed state.

For example, as shown in FIG. 5 (a), the area ranges of a hardness (high hardness) that is greater than or equal to a value in a predetermined range, a hardness (small hardness) in a predetermined range, and a hardness that is less than or equal to a value that is low in hardness. As shown in FIG. 5 (b), the temperature is a temperature that is a predetermined range of values (red), a predetermined range of values (pink), and a lower temperature (light blue). Each area position and range is shown to correspond approximately. Therefore, if the temperature distribution of the ground section BS is measured, for example, the ground hardness state which is the property of the ground section BS can be determined, and as a result, the supporting force of the ground with respect to the structure can be determined. In FIG. 5A, “no stress transmission” indicates a hardness of 0.15 (N / mm ² ) or less, and “low hardness” indicates 0.15 to 0.30 (N / mm ² ). The “high hardness” range is shown as a range of 0.30 to 0.40 (N / mm 2). And in FIG.5 (b), "light blue" is a range whose temperature difference is 0-0.5 degreeC with respect to the ground temperature before penetrating a pile, and "pink" is 0.5- The range of 0.8 ° C., “red” is shown as the range of 0.8 to 1.0 ° C. It goes without saying that the color display shown here can be arbitrarily set in the infrared thermal screen device 20.

  As shown in FIG. 5, when the area range showing a high temperature is displayed in red, the larger the area range of the color close to red, the more the ground is affected by the penetration of the piles 12. In addition, when the temperature of the ground is high, the hardness of the ground is large, which means that if the area range close to red is distributed around the pile 12, the supporting force for the ground is increased. It can be said that. Although not shown, conversely, if the area range where the temperature is low is widely distributed around the pile 12, the supporting force of the pile 12 on the ground is not small with the influence of the disturbance on the ground. It can be said.

  In addition, in the pile 12 which penetrated by rotating, the tip support force, frictional resistance, etc. can be determined from the temperature distribution. In other words, when an extreme vertical load is applied to the tip of the pile 12 by rotating the pile 12 in, the surroundings of the pile 12 and the ground at the tip are destroyed, and the change in the density of soil particles appears. The state of density change of soil particles can be grasped by the temperature distribution.

  In addition, as shown in FIG. 6, by performing extraction operation step S2a between the structure penetration step S2 and the ground cross-section formation step S3, the relationship between the ground pressure distribution and the frictional resistance in the extraction of the structure 12, It can be determined from an image showing the temperature distribution of the ground cross section. When performing this extraction operation step S2a, as shown in FIG. 7, in addition to the configuration already described, the bottomed mold 30 has a stopper for preventing the formed ground B from completely slipping out of the bottomed mold 30. It is convenient to include a peripheral edge 34 and a fixing flange 33 for preventing the bottomed mold 30 itself from being lifted.

  Therefore, in the ground property determination method SB including the pulling-out operation step S2a, the pile 12 penetrated by the structure penetration step S2 is raised in the axial direction with a force set in advance, for example, via the lifting mechanism 14 of FIG. After that, the ground section forming step S3 described above and other steps are performed to move a part of the pile 12 in the ground direction, and the temperature distribution of the ground section BS is measured from the image of the ground section BS. The property can be determined. In addition, the state of the temperature distribution in the ground cross section when the drawing operation step S2a is performed is shown in FIG. FIGS. 8A to 8E are cross-sectional views schematically showing a state in which the properties of each structure used in the ground property determination method can be visually recognized. As shown in FIG. 8D, it can be seen that when the drawing operation step S2a is performed, the temperature distribution is different from the state of FIG. 8A. That is, the state of the temperature distribution generated by the pulling operation of the pile 12 by the pulling operation of the pile 12 is shown in a fan shape, and the property of the ground cross section BS by the pulling operation can be determined.

  In addition, as shown in FIG.8 (b), when the uniform rod-shaped pile 12A is penetrated into the ground B by predetermined construction conditions from the front-end | tip to a rear end, compared with the state of Fig.8 (a). In the case of the pile 12A and the case of the pile 12, it can be seen that the temperature distribution state shown in the ground section BS is different. Similarly, as shown in FIG. 8C, it can be determined that the state of the temperature distribution of the ground section BS of FIG.

  Therefore, as shown in FIGS. 8A to 8D, the ground property determination methods SA and SB are applied to piles 12, 12A, 12B having different shapes, or a ground section BS obtained by applying different forces to the ground. The state of properties can be recognized. Therefore, when a construction problem (for example, bearing capacity) occurs in a structure at the site, the cause for investigating the problem with the construction status is visually searched, or a new structure It is convenient because it can be visually determined by searching for a hint when searching for a construction method by observing the temperature distribution of the cross section of the ground using the characteristics of the ground as a learning material.

  Moreover, as shown in FIG.8 (e), it becomes possible to determine the property of the ground B by the leg 12C as a T-shaped structure which does not penetrate the ground B. A ground property determination method SC (see FIG. 6) for determining the property of the leg 12C with respect to the ground B will be described with reference to FIG. In addition, about the structure already demonstrated, the same code | symbol is attached | subjected and description is abbreviate | omitted. In addition, the ground property determination method SC performs a structure pressing step Sb instead of the structure penetration step S2 of the ground property determination method SA in FIG.

  As shown in FIG. 9A, the ground formation step S1 is performed, and then, as shown in FIG. 9B, the T-shaped leg body 12C, which is a structure, is formed on the formed ground B. A structure pressing step Sb for pressing with a predetermined pressing force is performed. In this structure pressing step Sb, the ground B is pressed at a predetermined time using a leg 12C instead of the pile 12 shown in FIG.

Further, the leg body 12C is raised, and the ground cross section forming step S3, the temperature distribution measuring step S4, and the determining step S5 are performed. The temperature distribution measurement step S4 can be performed more quickly after raising the leg 12C, thereby making it possible to measure the temperature distribution of the ground section BS more clearly.
In addition, you may perform each step after ground cross-section formation step S3, pressing leg 12C.
As described above, in the ground property determination method SC, the property of the ground when the leg 12C is pressed against the ground B can be determined by measuring the temperature distribution.

[Example]
Next, an embodiment of the present invention will be described with reference to FIGS. The ground property judging device used in this example is shown in FIG. Here, the effect of the difference in the penetration speed on the disturbance of the outer periphery of the pile is shown in FIG. 11 for a pile with four types of penetration speeds with a single pile spiral wing and a constant rotation speed of 40 times / min. As shown in FIG. 4, the determination was made from an image showing hardness measured by a pocket penetrometer (right column), an image showing changes in the colored layer (center column), and an image showing temperature distribution by thermography (left column).

  As shown in FIG. 10 (a), the pile that rotates and becomes the structure to be used has a shaft diameter of 48.7 mm, a spiral blade diameter of 72.8 mm, a pitch at which the spiral blade is formed, 13.7 mm, and a tip. A drilling blade having a height of 18.2 mm was used. Moreover, the model soil tank as a bottomed formwork was made of steel, and had a diameter of 260 mm and a height of 500 mm. This model soil tank (hereinafter referred to as a soil tank) is divided into two parts, and is configured so that the ground can be cut in the vertical direction after the pile has penetrated.

The ground used was Kasaoka clay and No. 7 silica sand, which was formed by adding 7% of Kasaoka clay to No. 7 silica sand 3 and adding 7% of water to 1 kg of the mixed soil. The reason why the mixed soil was set to 7 to 3 was that it was found that this ratio best reflects the image of the thermography here. And the thing shown in FIG.10 (b) was used for the soil grain of this ground. And this earth grain was divided into 5 times and thrown into the earth tub, and it was squeezed 10 times with the mallet each time, and was compacted. The ground has a dry density after compaction of 1.02 t / m ³ . In addition, colored sand (colored in either Kasaoka clay or No. 7 type silica sand) was arranged so that the layer could be understood at each input.

  Thus, with respect to the artificially formed ground, the rotation speed was fixed at 40 times / min, and the piles were penetrated at four types of penetration speeds (45, 90, 270, 450 mm / min). When each penetration speed is expressed by the amount of penetration per one time, it is 1.125 mm at 45 mm / min, 2.250 mm at 90 mm / min, 6.750 at 270 mm / min, and 450 mm / min. In the case of min, it was 11.250 mm.

  After penetrating the pile into the ground, open half of the side wall and remove half of the ground to form a cross section of the ground, place a 22mm mesh frame, and set the hardness of the ground at the intersection of the mesh to the pocket penetro The temperature was measured with a meter, the temperature distribution of the ground section was measured with thermography, and the ground section was photographed as an image. The state is shown in FIG. In FIG. 11, at each penetration speed, the center row is an image in which colored sand can be visually recognized, the image of the left example shows the distribution of ground hardness, and the image in the right column of the center row shows the temperature distribution of the ground. . In addition, the distribution of the ground hardness of the ground cross section was also performed before penetrating the pile, and the penetration input amount was 5 to 10 N in the measurement with the pocket penetrometer. Similarly, the temperature distribution of the ground cross section before the penetration of the pile was measured, and the measurement temperature was 1 ° C.

  FIG. 12 is a graph showing the relationship between the depth of the ground, the rotational speed of the pile (structure), and the torque, and the torque when the penetration speed is 45 mm / min and 90 mm / min is in the depth direction. It can be seen that it continues to increase. It can also be seen that when the penetration speed is 270 mm / min, the torque is constant from a depth of 200 mm, and when the penetration speed is 450 mm / min, the torque is constant from a depth of 150 mm. This suggests that the penetration properties of the piles are significantly different.

  As shown in FIG. 11, in the ground cross section when the penetration speed is 45 mm / min and 90 mm / min, the penetration input amount increased to 55 to 60 N in the ground outside the pile according to the measurement with the pocket penetrometer (5 to 60 N). Greatly increased compared to 10N). On the other hand, in the cross section of the ground at the penetration speeds of 270 mm / min and 450 mm / min, it is reduced to 5 N or less, and it is apparent that the pile outer peripheral ground is disturbed. It can be seen that the disturbance in the state of the outer periphery of the pile is apparent from the image showing the temperature distribution corresponding to the distribution of the ground hardness.

That is, when the pile is penetrated under conditions of penetration speeds of 270 mm / min and 270 mm / min, as shown in FIGS. 11 (c) and 11 (d), a cavity is formed around the pile in the center row, This shows that the influence on the ground after the piles are penetrated is great. The state in which a cavity is formed around this pile also corresponds to the measurement results of the hardness distribution and temperature distribution shown in the left and right columns.
On the other hand, when the pile is penetrated under conditions of penetration speeds of 45 mm / min and 90 mm / min, as shown in FIGS. 11 (a) and (b), in the center row, a cavity is formed around the pile. There wasn't. Furthermore, in the case of the penetration speed of 45 mm / min, it can be seen that the range in which the influence around the ground around the pile is strongly influenced is wide compared to the case of 90 mm / min. When the penetration speed is 90 mm / min, compared to 45 mm / min, as shown in FIG. 11B, the range of small influence is wide in the left column, but the range that strongly affects the ground is narrow. I understand that. Therefore, when the penetration speed is 90 mm / min, the shape of the spiral blade and the penetration speed are in an optimum relationship as compared with other conditions, indicating that the construction state is in a good state.

  In the image showing the ground cross section, it is measured that the temperature rises from 1 ° C. to around 2 ° C., and the temperature distribution of the temperature rise varies depending on the penetration speed of the pile. The temperature rise in the ground (ground cross-section) is thought to be due to the movement of soil particles as the pile penetrates, and the frictional heat between the soil particles generated by the movement and the friction between the spiral blade and the soil. Since the range showing the high temperature region here is relatively narrow, it is considered that FIGS. 11A and 11B show a state in which the propulsive force of the spiral blade is acting in FIGS. On the other hand, in FIG.11 (d), since the range which shows a high temperature area | region around the pile is comparatively wide, a temperature rise range is wide and forced by the pushing force from the raising / lowering mechanism 14 (refer FIG. 1). It is thought that it represents the state of penetration.

  As described above, by measuring the temperature distribution of the ground cross section and displaying it on the screen, the ground properties can be determined from the distribution state and ratio by color in the displayed image. It can be seen that the results are almost the same as the results obtained with a measuring instrument such as a hardness measuring instrument.

It is a mimetic diagram showing typically the whole ground property judging device concerning the present invention. (A)-(e) is a perspective view which shows typically each step of the ground property determination method which concerns on this invention. (A)-(e) is a perspective view which shows each state of the ground cross section formed by the ground cross section step in the ground property determination method based on this invention. (A), (b) is a perspective view which shows an example which measures the hardness distribution of a ground section, when comparing the temperature distribution of the ground section used by this invention, and the hardness distribution of a ground section. (A), (b) is the front view of the image which shows the state which compared the temperature distribution of the ground cross section used by this invention, and the hardness distribution of a ground cross section. It is a flowchart figure which shows the flow of the ground property determination method which concerns on this invention. (A), (b) is a perspective view which shows typically the state of the extraction operation | movement step in the ground property determination method which concerns on this invention. (A)-(e) is sectional drawing typically shown as a state which can recognize visually the property in the ground section of each structure used with the ground property judging method concerning the present invention. (A)-(e) is a perspective view which shows typically each step in the other ground property determination method which concerns on this invention. (A) is a graph which shows the relationship between the particle size of the soil grain used for the ground in the Example of the ground property determination method which concerns on this invention, and passage mass percentage, (b) shows the structure of the front-end | tip part of a pile. It is a schematic diagram. (A)-(d) are the ground hardness distribution image (left column), the ground visual image (center column), and the ground temperature distribution image (right column) in the embodiment of the ground property determination method according to the present invention. It is a schematic diagram which shows the compared state typically. It is a graph which shows the relationship between the depth of a ground, the rotational speed of a structure, and a torque in the Example of the ground property determination method which concerns on this invention.

Explanation of symbols

SA Ground property judgment method SB Ground property judgment method SC Ground property judgment method B Ground BS BS Cross section S1 Ground formation step S2 Structure penetration step S2a Drawing operation step S3 Ground cutting step S4 Ground cross section measurement step S5 Ground cross section judgment step 10 Judgment device 11 Frame 12 Pile (structure)
13 Rotating mechanism (penetration mechanism)
14 Lifting mechanism (penetration mechanism)
15 removing mechanism 17 engaging portion 20 infrared thermal image device 21 infrared thermal measuring section 22 measuring the display unit L1 slide mechanism L2 slide mechanism 30 having a bottom mold 31 type bottom 32 flange BS ₁ to BS ₅ Ground sectional M frame m mesh

Claims (7)

It is a ground property determination method for measuring the temperature of the ground section in the ground pressed by the structure, and determining the property of the ground from the measured temperature distribution,
A ground formation step for artificially forming and storing the ground in the bottomed formwork;
A structure pressing step for pressing the structure pressed against the ground from the opening side of the bottomed formwork, against the ground according to preset construction conditions;
A ground cross-section forming step for opening at least a part of a side surface of the bottomed formwork of the ground pressed by the structure and forming a ground cross-section of the ground pressed by the structure;
A temperature distribution measuring step for measuring the temperature distribution of the ground section with respect to the ground section of the ground within a preset time after pressing the structure against the ground,
From the image showing the temperature distribution of the measured cross section of the ground, a determination step of determining the properties of the ground by the distribution state and ratio by color,
A ground property judging method comprising: A ground property determination method for measuring the temperature of the outer peripheral ground of a structure penetrating into the ground and determining the property of the ground from the measured temperature distribution,
A ground formation step for artificially forming and storing the ground in the bottomed formwork;
A structure penetration step for penetrating a structure penetrating into the ground from the opening side of the bottomed formwork according to preset construction conditions;
Opening at least a part of the side surface of the bottomed formwork of the ground into which the structure has penetrated, removing at least a part of the ground in the ground or a part of the ground so that the periphery of the penetration part appears. A ground section forming step for forming a section;
A temperature distribution measuring step for measuring the temperature distribution of the ground cross section with respect to the ground cross section of the ground within a preset time after the structure has penetrated the ground; and
From the image showing the temperature distribution of the measured cross section of the ground, a determination step of determining the properties of the ground by the distribution state and ratio by color,
A ground property judging method comprising:   In the ground formation step, the ground is mixed soil in which silica sand and clay are mixed at a ratio of 9: 1 to 1: 9, and the mixed soil has a moisture content of 3 to 30%. The ground property determination method according to claim 1 or 2, wherein the ground property is added so as to have a ratio of the above.   The ground property determination method according to claim 2, wherein the ground cross section exposed in the ground cross section forming step is a cross section in which a half circumferential surface around an axis of the structure is exposed with the structure as a center.   5. The structure according to claim 2, wherein the structure is a pile in the structure penetration step, and the construction condition causes the pile to penetrate into the ground at a preset penetration speed. Method for determining the ground properties.   3. The ground according to claim 2, wherein a pulling operation step is performed between the structure penetrating step and the ground cross-section forming step to move the penetrating structure in a direction of pulling out from the ground with a preset force. A property determination method. A ground property judging device for judging the properties of the outer peripheral ground of the structure penetrating into the ground or the properties of the ground pressed by the structure from the temperature distribution,
A bottomed mold for storing the artificially formed ground, a penetration mechanism for pressing or penetrating the structure into the ground in the bottomed mold according to preset construction conditions, and the penetration mechanism With respect to the ground pressed by the structure or the ground penetrated through the structure, a part of the ground is removed to form a ground cross section in a state where a part of the side surface of the bottomed formwork is released. Or a removal mechanism that removes the ground to form a ground section so that at least a part of the structure penetrating the ground is exposed, and the ground section that is formed by removing with the removal mechanism. An infrared thermal imager that measures a temperature distribution and displays it on a screen with a distribution state and a ratio of each color in the ground section, and a ground property determination device.

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