JP6993296B2 - Cutting edge penetration width measuring device and caisson subsidence method - Google Patents

Description

The present invention relates to a cutting edge penetration width measuring device for measuring the penetration width of a caisson cutting edge into the ground and a caisson subsidence method.

As one of the construction methods for foundation work of building structures and construction of underground structures, for example, there is a caisson subsidence construction method disclosed in Patent Document 1 and the like. In this construction method, caissons (boxes) such as pneumatic caissons, which are formed in a bottomed tubular shape and have a working room for ground excavation at the bottom of the cylinder, and open caissons, which are formed in a bottomless tubular shape, are placed on the ground. Then, while excavating the ground inside the peripheral wall of the caisson and the ground below the cutting edge at the lower end of the peripheral wall, the caisson is gradually submerged to a predetermined depth by its own weight or by applying a load, and the ground is installed. It is a construction method for constructing foundations and underground structures inside.

In the caisson subsidence method in this type of construction method, the subsidence force (mainly the caisson's own weight), which is the force to subside the caisson, and the subsidence resistance from the ground, etc., which is the force to resist this subsidence force, are balanced. In the state, the caisson is stationary without sinking. This sinking resistance force mainly consists of a peripheral frictional force acting on the outer surface of the peripheral wall of the caisson and a reaction force (ground reaction force) from the ground acting on the inner peripheral surface of the cutting edge of the caisson. Specifically, the inner peripheral surface of the cutting edge is formed in a tapered shape that is inclined so as to approach the central axis side of the caisson toward the upper side from the tip of the cutting edge, and this inclined inner peripheral surface is formed from the ground. The reaction force is acting. Then, in the method of submerging the caisson, for example, the caisson is made to penetrate into the ground and is stationary, and a part of the lower ground on the inner peripheral surface of the caisson is excavated from the inside of the caisson. , The reaction force from the ground acting on the caisson is moderately reduced. As a result, the settlement resistance becomes lower than the settlement force, and the caisson begins to sink.

Japanese Unexamined Patent Publication No. 10-37203

Here, in this type of caisson subsidence method, the penetration width of the cutting edge of the caisson into the ground represents the width of the reaction force from the ground acting on the caisson, that is, the action width (acting area) of the ground reaction force. Therefore, it is one of the important parameters for construction management of caisson subsidence.

The present invention has been made by paying attention to such an actual situation, and is a blade intrusion width measuring device capable of measuring the penetration width of the blade into the ground in real time, and a caisson subsidence method using the device. The purpose is to provide.

In response to the above problems, the cutting edge penetration width measuring device according to the present invention is attached to an inclined inner peripheral surface of the caisson cutting edge, and is at least vertically along the inner peripheral surface. A sensor portion that extends, and when the cutting edge portion penetrates into the ground as the caisson sinks into the ground, the tip of the cutting edge portion of the portion of the inner peripheral surface that penetrates the ground. A sensor unit that outputs an identification signal that can identify the height range from the above, and a main body unit that calculates and measures the penetration width of the cutting edge portion into the ground based on the identification signal from the sensor unit. ,including.

Further, as one aspect of the caisson subsidence method according to the present invention, the caisson is used while adjusting the excavation amount of the ground below the blade edge portion by using the measurement result of the blade edge portion penetration width measuring device. Install by submerging from the ground surface side of the ground to a predetermined depth.

According to the above aspect of the cutting edge penetration width measuring device according to the present invention, when the cutting edge penetrates into the ground as the cason sinks into the ground, it is attached to the inclined inner peripheral surface of the cutting edge. In addition, the sensor unit that extends at least in the vertical direction along the inner peripheral surface outputs an identification signal that can identify the height range from the tip of the cutting edge for the portion of the inner peripheral surface that penetrates the ground. The main body calculates and measures the penetration width of the cutting edge into the ground based on the identification signal from the sensor. As a result, when the caisson is sunk, the measurement result of the penetration width of the cutting edge into the ground can be constantly obtained, so that the action width (action) on which the reaction force from the ground acts on the inner peripheral surface of the cutting edge of the caisson. Area) can be monitored in real time with a simple structure (configuration). Then, by estimating the total reaction force from the ground in real time based on the measurement result of the intrusive width, the construction management of the caisson subsidence can be performed more reliably and safely.

According to the above aspect of the caisson subsidence method according to the present invention, the caisson is placed on the ground surface side of the ground while adjusting the excavation amount of the ground below the blade edge portion by using the measurement result of the blade edge portion penetration width measuring device. It is configured to be installed by sinking to a predetermined depth. Therefore, for example, the total reaction force from the ground at the present time is estimated in real time based on the measurement result of the penetration width of the cutting edge into the ground obtained by the cutting edge penetration width measuring device, and this estimation is mainly performed. The subsidence resistance force consisting of the total reaction force from the ground and the peripheral friction force acting on the peripheral wall of the caisson is moderately lower than the subsidence force (mainly the weight of the caisson). The amount of excavation can be adjusted to initiate the subsidence of the caisson. As a result, the caisson can be safely subsided and installed from the ground surface side of the ground to a predetermined depth.

In this way, it is possible to provide a blade edge portion penetration width measuring device capable of measuring the penetration width of the blade edge portion into the ground, and a caisson subsidence method using the device.

It is a conceptual diagram for demonstrating the schematic structure of the cutting edge penetration width measuring apparatus which concerns on one Embodiment of this invention, and the cason laying method using the measurement result of the cutting edge penetration width measuring apparatus. FIG. 1 is a cross-sectional view taken along the line XX of FIG. It is a conceptual diagram for demonstrating the schematic structure of the said cutting edge penetration width measuring apparatus. This is an example of an enlarged cross-sectional view of a main part including a sensor part of the cutting edge portion penetration width measuring device. It is another conceptual diagram for demonstrating the caisson laying method using the measurement result of the cutting edge penetration width measuring apparatus. It is an enlarged sectional view of the main part for demonstrating the deformation example of the sensor part. It is an enlarged sectional view of the main part for demonstrating another modification of the sensor part.

Hereinafter, embodiments of the blade edge penetration width measuring device and the caisson subsidence method according to the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a conceptual diagram for explaining a schematic configuration of a cutting edge penetration width measuring device 100 according to an embodiment of the present invention and a cason laying method using the measurement results of the cutting edge penetration width measuring device 100. .. FIG. 2 is a cross-sectional view taken along the line XX of FIG. In the present embodiment, the pneumatic caisson 1 is used as a caisson, and the caisson subsidence method for constructing a foundation such as a pier by submerging the pneumatic caisson 1 is applied to the cutting edge penetration width measuring device 100 according to the present invention. The case where the caisson subsidence method using the measurement result is applied will be described below.

First, the schematic structure and the like of the pneumatic caisson 1 will be described.

The pneumatic caisson 1 has a predetermined cross-sectional shape such as a cylinder or a square cylinder, and has a peripheral wall 2 having a cylindrical shape and extending in the vertical direction. In the present embodiment, the pneumatic caisson 1 has a substantially cylindrical shape as a whole and is divided into a predetermined number in the vertical direction. Consists of the omitted caisson top. FIG. 1 shows a state in which the pneumatic caisson 1 is being constructed. Specifically, it is shown that most of the caisson base 3 of the pneumatic caisson 1 is subsided in the ground G and is stationary.

The peripheral wall 2 is composed of a caisson base 3, an intermediate portion of the caisson, and an outer peripheral wall of the top of the caisson. For example, the caisson middle portion and the caisson top are each formed to have an outer diameter slightly smaller than the maximum outer diameter of the caisson base 3.

The caisson base 3 constitutes the lowermost end portion of the pneumatic caisson 1 and includes a cylindrical portion 3a and a partition wall portion 3b.

The cylindrical portion 3a is formed in a cylindrical shape and extends in the vertical direction to form a lower end portion of the peripheral wall 2 of the pneumatic caisson 1. The inner space inside the cylindrical portion 3a in the radial direction is vertically divided into two by the partition wall portion 3b, and the lower space constitutes a work room R to be described later for ground excavation. The lower end portion of the cylindrical portion 3a constitutes the cutting edge portion 4. As shown in FIG. 1, the blade edge portion 4 is a portion that penetrates into the ground G (specifically, the lower ground G2 described later) when the caisson sinks, and is formed in a substantially cylindrical shape. The inner peripheral surface 4a of the cutting edge portion 4 is formed in a tapered shape that is inclined so as to approach the central axis Z side of the pneumatic caisson 1 toward the upper side (in other words, the partition wall portion 3b side) from the cutting edge portion tip 4b. ing. Specifically, the inclination angle of the inner peripheral surface 4a at the lowermost end of the blade edge portion 4 (that is, the inclination angle of the inner peripheral surface 4a with respect to the central axis Z) is, for example, from the inclination angle of the inner peripheral surface 4a above the inner peripheral surface 4a. Is also set to be large.

Further, the cylindrical portion 3a is specifically formed to have a stepped outer peripheral surface so that the outer diameter on the upper end side thereof is slightly smaller than the outer diameter on the lower end side. The outer peripheral wall of the caisson intermediate portion and the caisson top portion is formed with an outer diameter that matches the outer diameter of the upper end side of the cylindrical portion 3a. The outer peripheral surface of the cylindrical portion 3a is not limited to the stepped shape, and may have the same outer diameter. In this case, the peripheral frictional force acting on the cylindrical portion 3a (peripheral wall 2) forming a part of the subsidence resistance force against the pneumatic caisson 1 is larger than that in the stepped shape.

The work room R is a space for excavating the ground by a worker, an excavator 5 or the like described later, and is partitioned by an inner peripheral surface 4a of the cutting edge portion 4 and a partition wall portion 3b. Air or the like is supplied from the outside into the work room R, and the inside of the work room R is in a pressurized state. As a result, the inflow of groundwater, mud, gas, etc. from the ground into the work room R is suppressed or prevented, and the safety and efficiency of the excavation work are improved. The lifting pressure generated by the pressure in the working chamber R constitutes a part of the subsidence resistance force that opposes the subsidence force of the pneumatic caisson 1.

As described above, the partition wall portion 3b is a portion that divides the inner space inside the cylindrical portion 3a in the radial direction into two in the vertical direction and serves as the ceiling wall of the work room R. In the present embodiment, a guide rail 6 for a traveling guide of the excavator 5 is attached to the wall surface (lower surface) of the partition wall portion 3b on the work room R side. The excavator 5 excavates the ground G1 inside the cutting edge 4 and the lower ground G2 located below the cutting edge 4 in the ground G, for example, remote from outside the work room R. By operation, the ground G1 and the lower ground G2 can be excavated by traveling along the guide rail 6 and moving to the vicinity of the excavation target area. The boundary between the ground G1 inside the cutting edge portion 4 and the lower ground G2 is not strictly separated. Further, although not shown, an image pickup camera for monitoring the inside of the work room R is attached to the wall surface of the partition wall portion 3b on the work room R side. The operator or the like of the excavator 5 remotely controls the excavator 5 on the ground side, for example, while monitoring the image captured by the image pickup camera.

Further, the partition wall portion 3b is opened at a position where the through hole 3b1 does not interfere with the guide rail 6. The through hole 3b1 communicates between the internal space of the tubular man lock 7 and the material lock 8 installed on the upper wall surface of the partition wall portion 3b at the time of caisson subsidence construction and the work room R. In FIG. 1, a through hole 3b1 for communicating with the internal space of the man lock 7 and a through hole 3b1 for communicating with the internal space of the material lock 8 are shown. Although not shown, the piping for pressure air in the work room R and the through holes for gas monitoring in the work room R are formed at appropriate positions, respectively. The man lock 7 is formed with a staircase that reaches the work room R from the upper opening through the lower opening, and the worker can enter the work room R through this staircase. .. Further, the man lock 7 is provided with a decompression chamber in the middle, and the worker can leave to the ground side via the decompression chamber after the work in the pressurized work chamber R is completed. The material lock 8 is used when the earth and sand excavated in the work room R are discharged by a crane or the like.

Here, at the time of caisson subsidence construction, the blade edge portion 4 of the caisson base 3 penetrates into the lower ground G2 as shown in FIG. Since the inner peripheral surface 4a of the blade edge portion 4 is inclined, the penetration width B, which is the width of the blade edge portion 4 penetrating into the lower ground G2, is the penetration depth of the blade edge portion 4 into the lower ground G2. The deeper it is (in other words, the higher the height range H described later), the wider it becomes. The penetration width B is, specifically, the width in the horizontal direction (that is, the direction orthogonal to the central axis Z of the pneumatic caisson 1) with respect to the inner peripheral surface 4a of the cutting edge portion 4 in contact with the lower ground G2. say. Further, the penetration width B can be said to represent the width at which the reaction force from the lower ground G2 acts on the caisson base 3, that is, the action width (acting area) of the ground reaction force forming a part of the subsidence resistance force. In a sense, it is one of the important parameters for construction management of caisson subsidence. As the penetration width B becomes narrower, the total ground reaction force acting on the cutting edge portion 4 becomes smaller, and the subsidence resistance force becomes smaller.

Next, the blade edge portion penetration width measuring device 100 will be described with reference to FIGS. 1 to 4. FIG. 3 is a conceptual diagram for explaining a schematic configuration of the blade edge portion penetration width measuring device 100, and FIG. 4 is an example of an enlarged cross-sectional view of a main part of the blade edge portion penetration width measuring device 100.

The cutting edge penetration width measuring device 100 is a device for measuring the penetration width B of the cutting edge portion 4 into the ground G (lower ground G2) when the pneumatic caisson 1 is laid down, and is shown in FIGS. 1 and 3. As shown, the sensor unit 10 and the main body unit 20 are included.

As shown in FIG. 1, the sensor unit 10 is attached to the inclined inner peripheral surface 4a of the blade edge portion 4 of the pneumatic caisson 1 and extends at least in the vertical direction along the inner peripheral surface 4a. Then, as shown in FIG. 1, when the cutting edge portion 4 penetrates into the ground G due to the subsidence of the pneumatic caisson 1 into the ground G (lower ground G2), the sensor portion 10 penetrates the ground G on the inner peripheral surface 4a. It outputs an identification signal S capable of identifying the height range H from the tip end 4b of the cutting edge portion for the portion penetrating into the blade.

In the present embodiment, as shown in FIG. 2, the sensor unit 10 is provided at a plurality of locations (12 locations in the figure) separated from each other in the circumferential direction of the inner peripheral surface 4a. Specifically, the sensor unit 10 is arranged at an equal angle pitch in the circumferential direction of the inner peripheral surface 4a (that is, around the central axis Z). Further, each sensor unit 10 is embedded in a concave groove formed in the inner peripheral surface 4a, and is attached so as not to protrude from the inner peripheral surface 4a toward the work room R side. Each of the sensor units 10 embedded in the concave groove has a sensing surface flush with the inner peripheral surface 4a, and outputs an identification signal S, respectively. More specifically, the sensor portion 10 is attached to an upper portion of the inner peripheral surface 4a inclined in two stages, avoiding the portion of the tip 4b of the cutting edge portion.

In the present embodiment, each sensor unit 10 is composed of a pressure sensor group 11 that outputs a signal corresponding to the pressure from the ground G acting on the inner peripheral surface 4a as an identification signal S, respectively. The pressure sensor group 11 is composed of, for example, a plurality of elements, and each element outputs a signal corresponding to the pressure as an identification signal S. Specifically, the pressure sensor group 11 will be described below assuming that the pressure sensor group 11 is composed of a sensor array formed integrally by arranging a plurality of piezoelectric elements in a row at intervals in one direction in the vertical direction. The pressure sensor group 11 is not limited to the sensor array, but is a surface pressure sensor integrally formed by arranging a plurality of piezoelectric elements in a planar (two-dimensional) array at intervals in the vertical direction and the circumferential direction. An appropriate sensor such as the above can be used.

For example, as shown in FIG. 4, it is assumed that the cutting edge portion 4 penetrates into the lower ground G2. In this state, among the plurality of piezoelectric elements in the pressure sensor group 11, the element that penetrates into the lower ground G2 and is in contact with the lower ground G2 (residual soil left behind) (hereinafter, these elements are appropriately contacted with each other). The reaction force from the lower ground G2 acts on). Therefore, each of these contact elements outputs a signal corresponding to the ground reaction force as an identification signal S. On the other hand, the reaction force from the lower ground G2 acts on the elements exposed in the work room R among the plurality of piezoelectric elements in the pressure sensor group 11 (hereinafter, these elements are appropriately referred to as exposed elements). Not done. Therefore, these exposed elements output a reference level signal indicating zero pressure as the identification signal S. Therefore, the magnitude of the signal level (for example, voltage value) of the identification signal S output from each of the plurality of piezoelectric elements in the pressure sensor group 11 changes rapidly between the contact element and the exposed element. The magnitude of the signal level from the exposed element is sharply lower than the magnitude of the signal level from the contact element.

The main body 20 calculates and measures the penetration width B of the blade edge 4 into the ground G based on the identification signal S from the sensor 10, and includes a storage unit including a memory and the like, a CPU, and the like. It is configured to include a calculation unit. The identification signal S from each of the plurality of piezoelectric elements in each pressure sensor group 11 is constantly input to the main body 20 for each pressure sensor group 11.

The storage unit of the main body 20 stores structural data such as the dimensions of the pneumatic caisson 1 and data that can specify the mounting position of each pressure sensor group 11. Specifically, in the storage unit, as the data of the mounting position of the pressure sensor group 11, the mounting angle data around the central axis Z on the inner peripheral surface 4a and each of the plurality of piezoelectric elements are obtained for each pressure sensor group 11. The coordinate data of the height position in the stretching direction of the central axis Z with respect to the tip 4b of the cutting edge portion of the above is stored. Then, each identification signal S is input to the main body portion 20 so that it can be discriminated from which height position of the pressure sensor group 11 at which mounting angle position the signal is from the piezoelectric element.

The calculation unit of the main body unit 20 calculates and measures the penetration width B for each pressure sensor group 11. The calculation unit, for example, samples the identification signal S constantly input from the pressure sensor group 11 at predetermined sampling times. Then, based on this sampling data, the calculation unit calculates the penetration width B at the mounting angle position of the pressure sensor group 11 for each pressure sensor group 11 in parallel for each sampling time.

For example, to explain the calculation of the penetration width B based on the identification signal S from one pressure sensor group 11 mounted at a predetermined angle position shown in FIG. 4, the calculation unit includes a plurality of piezoelectric elements in the pressure sensor group 11. The identification signal S of the signal level according to the ground reaction force is input from the plurality of the contact elements on the lower side of the contact element, and the reference indicating zero pressure from the plurality of the exposed elements above the plurality of the contact elements. The level identification signal S is input. Then, the arithmetic unit determines, for example, whether or not there is a change in the magnitude of the signal level of the plurality of piezoelectric elements, which is equal to or higher than a predetermined threshold value, based on the sampling data of each input identification signal S. judge. In the state shown in FIG. 4, the calculation unit determines that there is a change in the magnitude of the signal level of a predetermined threshold value or more between the plurality of contact elements and the plurality of exposed elements. Then, the calculation unit obtains, for example, the coordinate data of the piezoelectric element as the contact element having the largest coordinate data of the height position among the plurality of contact elements and the data of the inclination angle of the inner peripheral surface 4a. It is read from the storage unit, the penetration width B is calculated from the tilt angle data and the coordinate data, and is output as the measurement result of the penetration width B at the predetermined angle position shown in FIG. This calculation is performed for each pressure sensor group 11 in parallel at each sampling time, and as shown in FIG. 1, when the caisson base 3 is subsided without tilting, the penetration width for each pressure sensor group 11 is wide. The measurement results of B are substantially equal. As a result, it is possible to obtain a measurement result showing a state in which the penetration width B of the cutting edge portion 4 is substantially equal over the circumferential direction of the inner peripheral surface 4a as shown in FIG.

Here, when the caisson base 3 is constructed by sequentially stacking a predetermined number of the caisson intermediate portions in the vertical direction on the upper portion of the caisson base 3, the caisson base 3 is constructed together with the caisson intermediate portion. It sinks in the ground G. Further, when the caisson top is stacked on the uppermost portion of the caisson middle portion, the caisson base 3 sinks into the ground G together with the caisson middle portion and the caisson top. As a result, a pneumatic caisson 1 extending from the ground surface side to a predetermined subsidence depth is constructed in the ground G. Then, a pier or the like is installed on the upper part of the pneumatic caisson 1 (that is, the top of the caisson). Specifically, excavation of the inner ground G1 and the lower ground G2 in the work room R and the subsidence of the caisson due to this excavation are sequentially repeated up to the subsidence depth of the pneumatic caisson 1. That is, in a state where the cutting edge portion 4 penetrates into the lower ground G2 and stands still, when the lower ground G2 or the like is excavated in the work room R and the subsidence resistance becomes lower than the subsidence force, the caisson base 3 sinks. It begins to sunk and rests when it sinks by the expected amount. After that, excavation is performed again to subside by a predetermined amount, and this is repeated a plurality of times, and the middle portion of the caisson and the top portion of the caisson are sequentially stacked on the way.

Further, when excavating the lower ground G2 in contact with the inner peripheral surface 4a of the cutting edge portion 4 without limitation during excavation in the caisson subsidence construction, the subsidence resistance is sharply reduced and the caisson base 3 is not intended. There is a possibility that it will sink or sink (oversink) to a depth deeper than expected. Therefore, in order to safely start or restart the caisson subsidence, it is necessary to keep a part of the lower ground G2 in contact with the inner peripheral surface 4a of the cutting edge portion 4 even after excavation. Therefore, the current penetration width B of the cutting edge portion 4 into the lower ground G2 is the width of the remaining excavated soil left below the inner peripheral surface 4a at the present time and in contact with the ground, in other words, the magnitude of the reaction force from the ground. It is also a parameter that can be grasped. In this sense, the penetration width B is useful information for determining the excavation amount and the like as to how much the lower ground G2 of the cutting edge portion 4 can be excavated. The residual soil left over from the moat is the lower ground G2 itself, and is in contact with the inner peripheral surface 4a of the cutting edge portion 4 over the entire circumference in the working room R and exists below the inner peripheral surface 4a of the cutting edge portion 4. It is a generally circular remnant soil.

Next, an embodiment of the caisson subsidence method according to the present invention will be described with reference to FIGS. 1 and 5 in the case where the pneumatic caisson 1 is used as the caisson. FIG. 5 is an example of an enlarged view of the cutting edge portion 4 for explaining the caisson subsidence method of the present embodiment.

As mentioned above, in the caisson subsidence construction, excavation and subsidence are repeated. That is, when the subsidence of the caisson base 3 is stopped and the caisson base 3 is stationary, it is necessary to excavate the lower ground G2 again in order to restart the next subsidence. And, this excavation needs to be performed with an appropriate amount of excavation.

Therefore, in the caisson subsidence method in the present embodiment, the pneumatic caisson 1 is ground while adjusting the excavation amount of the lower ground G2 of the cutting edge portion 4 by using the measurement result of the cutting edge portion penetration width measuring device 100 described above. It is configured to be installed by sinking from the ground surface side of G to a predetermined depth.

Specifically, as shown in FIG. 5, in a state where the blade edge portion 4 penetrates into the lower ground G2 and the caisson base 3 is stationary, the blade edge portion penetration width measuring device 100 uses the current penetration width. Obtain the measurement result of B. Then, since the working width of the ground reaction force acting on the caisson base 3 (blade edge portion 4) at the present time can be known from the obtained penetration width B, the total ground reaction force acting on the cutting edge portion 4 can be estimated. .. Then, the amount of excavation of the lower ground G2 of the cutting edge portion 4 so that the subsidence resistance force consisting mainly of the total of the estimated ground reaction force and the peripheral friction force estimated in advance is appropriately lower than the subsidence force. To decide. Then, according to the determined excavation amount, the slope exposed on the work room R side in the lower ground G2 (remaining soil left over) is excavated toward the inner peripheral surface 4a side of the cutting edge portion 4. The shaded area in FIG. 5 is the excavation area. The portion shown by the alternate long and short dash line shown in FIG. 5 is the slope of the lower ground G2 (remaining soil left over from the moat) after excavation. Since the intrusive width B after excavation is appropriately narrower than the intrusive width B before excavation, the settlement resistance is moderately low, and the settlement resumes slowly. Then, the measurement of the intrusive width B is continued even during this subsidence, the intrusive width B increases with the subsidence, and the subsidence stops again when the predicted predetermined amount of subsidence occurs. This is repeated a plurality of times, and the intermediate portion of the caisson and the top of the caisson are sequentially stacked on the way to construct a pneumatic caisson 1 extending from the ground surface side to a predetermined subsidence depth in the ground G.

Further, during this subsidence construction, the caisson base 3 is required to be subsided in a substantially vertical direction. Therefore, a part of the lower ground G2 is excavated so that the excavation amount of the lower ground G2 (in other words, the width of the residual soil left over from the moat) becomes substantially uniform over the circumferential direction of the inner peripheral surface 4a. Due to this excavation, the caisson base 3 sinks in the substantially vertical direction without tilting, and the penetration width B of the cutting edge portion 4 becomes substantially equal over the circumferential direction of the inner peripheral surface 4a as shown in FIG. There is.

According to the cutting edge penetration width measuring device 100 according to the present embodiment, when the cutting edge 4 penetrates into the ground G (lower ground G2) as the pneumatic cason 1 sinks into the ground G, the cutting edge A portion that penetrates the ground G (lower ground G2) in the inner peripheral surface 4a by the sensor portion 10 that is attached to the inclined inner peripheral surface 4a in the portion 4 and extends at least in the vertical direction along the inner peripheral surface 4a. Outputs an identification signal S that can identify the height range H from the tip 4b of the cutting edge, and the main body 20 calculates the penetration width B of the cutting edge 4 based on the identification signal S from the sensor 10. And measure. As a result, when the caisson is sunk, the measurement result of the penetration width B of the cutting edge portion 4 can be constantly acquired, so that the acting width (acting area) on which the ground reaction force acts on the inner peripheral surface 4a of the cutting edge portion 4 can be simplified. Real-time monitoring is possible due to the various structures (configurations). Then, by estimating the total ground reaction force in real time based on the measurement result of the penetration width B, the construction management of the caisson subsidence can be performed more reliably and safely.

Further, according to the caisson subsidence method according to the present embodiment, the pneumatic caisson 1 is adjusted while adjusting the excavation amount of the lower ground G2 of the cutting edge portion 4 by using the measurement result of the cutting edge portion penetration width measuring device 100. It is configured to be installed by submerging it from the ground surface side of the ground G to a predetermined depth. Therefore, for example, the total ground reaction force at the present time is estimated in real time based on the measurement result of the penetration width B obtained by the cutting edge penetration width measuring device 100, and the total ground reaction force and the circumference are mainly estimated. The caisson subsidence can be started by adjusting the excavation amount of the lower ground G2 of the cutting edge portion 4 so that the subsidence resistance force including the surface friction force is appropriately lower than the subsidence force. As a result, the pneumatic caisson 1 can be safely subsided and installed from the ground surface side of the ground to a predetermined depth.

In this way, it is possible to provide a blade edge portion penetration width measuring device 100 capable of measuring the penetration width B of the blade edge portion 4, and a caisson laying method using the device.

Further, in the present embodiment, the sensor unit 10 is provided at a plurality of locations separated in the circumferential direction of the inner peripheral surface 4a. As a result, the intrusive width B can be monitored at a plurality of locations separated in the circumferential direction, and for example, it is possible to more reliably confirm whether or not the intrusive width B is subsided without being inclined.

In the present embodiment, the plurality of sensor units 10 are each composed of a pressure sensor group 11, that is, one type of sensor, but the present invention is not limited to this, and as shown in FIGS. 6 and 7. , May consist of a combination of a plurality of types of sensors.

For example, as shown in FIG. 6, the sensor unit 10 may be composed of a combination of the pressure sensor group 11 and the illuminance sensor group 12 that outputs a signal corresponding to the illuminance as the identification signal S. The illuminance sensor group 12 has a plurality of illuminance detecting elements 12a arranged in place of the plurality of piezoelectric elements in the pressure sensor group 11. In this case, for example, as shown in FIG. 6, the pressure sensor group 11 is provided in the lower portion in the vertical direction on the inner peripheral surface 4a, and the illuminance sensor group 12 is provided in the upper portion in the vertical direction on the inner peripheral surface 4a. It is good to install it in. Specifically, the pressure sensor group 11 and the illuminance sensor group 12 are arranged in a row so as to extend in the vertical direction as a whole. Then, apart from the threshold value for the change in the magnitude of the signal level among the plurality of piezoelectric elements in the pressure sensor group 11, the change in the magnitude of the signal level among the plurality of illuminance detection elements in the illuminance sensor group 12 The threshold value may be set. That is, when the penetration of the cutting edge portion 4 into the lower ground G2 (remaining soil left over from the moat) is stopped at the attachment position of the pressure sensor group 11 on the inner peripheral surface 4a, the calculation unit is a plurality of piezoelectric elements. It is determined that there is a change in the magnitude of the signal level above a predetermined threshold value between the contact element and the exposed element. As shown in FIG. 6, when the penetration of the cutting edge portion 4 into the lower ground G2 (remaining soil left over from the moat) extends to the mounting position of the illuminance sensor group 12 in the inner peripheral surface 4a, the above calculation is performed. The unit determines that there is a change in the magnitude of the signal level of a predetermined threshold value or more between the contact element and the exposure element among the plurality of illuminance detecting elements. As a result, in the lower part of the inner peripheral surface 4a where the ground reaction force can always act, the pressure sensor group 11 reliably detects the change in the ground reaction force, and while the possibility that the ground reaction force acts is low, the illuminance In the upper part of the inner peripheral surface 4a, which is likely to be exposed to the work room R with a constant illuminance, the penetration width B can be reliably measured by reliably detecting the illuminance change by the illuminance sensor group 12. ..

Further, as shown in FIG. 7, the sensor unit 10 may be composed of a combination of the pressure sensor group 11 and the temperature sensor group 13 that outputs a signal corresponding to the temperature as the identification signal S. The temperature sensor group 13 has a plurality of temperature detection elements 13a arranged in place of the plurality of piezoelectric elements in the pressure sensor group 11. Also in this case, for example, as shown in FIG. 7, the temperature sensor group 13 is provided on the upper portion of the inner peripheral surface 4a in the vertical direction, and the pressure sensor group 11 and the temperature sensor group 13 are arranged in a row and vertically as a whole. It is preferable to arrange it so as to extend in the direction. Then, apart from the threshold value in the pressure sensor group 11, a threshold value for a change in the magnitude of the signal level between the plurality of temperature detection elements in the temperature sensor group 13 may be set. As a result, in the lower part of the inner peripheral surface 4a where the ground reaction force can always act, the pressure sensor group 11 reliably detects the change in the ground reaction force, and while the possibility that the ground reaction force acts is low, the work is performed. In the upper part of the inner peripheral surface 4a that is exposed to the chamber R and can detect a temperature relatively lower than that in the ground G, the penetration width B is surely measured by surely detecting the temperature change by the temperature sensor group 13. can.

Further, in FIGS. 6 and 7, each of the sensor units 10 provided at a plurality of locations separated in the circumferential direction of the inner peripheral surface 4a is composed of a combination of two types of sensors, but the present invention is not limited to this. The pressure sensor group 11 and the illuminance sensor group 12 may be alternately provided in the circumferential direction of the inner peripheral surface 4a, or the pressure sensor group 11 and the temperature sensor group 13 may be alternately provided. Further, all the sensor units 10 may be the illuminance sensor group 12 or the temperature sensor group 13. Further, the sensor unit 10 is assumed to extend in the vertical direction, but the present invention is not limited to this, and for example, the sensor unit 10 may be provided over the entire circumference of the inner peripheral surface 4a. In this case, for example, a surface pressure sensor may be attached to the entire circumference of the inner peripheral surface 4a as the sensor unit 10 and laid. Further, the sensor unit 10 is provided at a plurality of locations, but the present invention is not limited to this, and the sensor unit 10 may be provided at only one location at a predetermined angle in the circumferential direction of the inner peripheral surface 4a.

Further, in the above description, the pneumatic caisson 1 is used as the foundation of the pier, but the pneumatic caisson 1 can be used not only as the pier but also as the foundation of other building structures. Further, the pneumatic caisson 1 can be used not only as a foundation of a building structure but also as an underground structure. Further, although the case where the pneumatic caisson 1 is used as the caisson has been described, the type of caisson is not limited to this, and a general open caisson made of a cylinder without a partition wall portion 3b may be used. Further, the caisson can be applied not only in a cylindrical shape but also in any shape such as a square cylinder shape.

Although the embodiments of the present invention and modifications thereof have been described above, the present invention is not limited to the above-described embodiments and modifications, and further modifications and modifications can be made based on the technical idea of the present invention. Of course.

1 ... Pneumatic caisson (caisson)
4 ... Blade edge portion 4a ... Inner peripheral surface 4b ... Blade edge portion tip 10 ... Sensor unit 11 ... Pressure sensor group 12 ... Illuminance sensor group 13 ... Temperature sensor group 20 ... Main body unit 100 ... Blade edge portion penetration width measuring device B ... Penetration width G ... Ground G2 ... Lower ground H ... Height range S ... Identification signal

Claims (7)

A sensor portion attached to an inclined inner peripheral surface of a caisson's cutting edge portion and extending at least in the vertical direction along the inner peripheral surface, and the cutting edge portion as the caisson sinks into the ground. When it penetrates the ground, it outputs an identification signal that can identify the height range from the tip of the cutting edge of the portion of the inner peripheral surface that penetrates the ground, and a sensor unit.
Based on the identification signal from the sensor unit, the main body unit that calculates and measures the penetration width of the blade edge portion into the ground, and
Intrusive width measuring device including the cutting edge. The blade edge portion penetration width measuring device according to claim 1, wherein the sensor unit is provided at a plurality of locations separated from each other in the circumferential direction of the inner peripheral surface. The sensor unit includes a pressure sensor group that outputs a signal corresponding to the pressure from the ground acting on the inner peripheral surface as the identification signal, an illuminance sensor group that outputs a signal corresponding to the illuminance as the identification signal, and The cutting edge penetration width measuring device according to claim 1 or 2, which includes at least one of a group of temperature sensors that outputs a signal corresponding to the temperature as the identification signal. The sensor unit includes a pressure sensor group that outputs a signal corresponding to the pressure from the ground acting on the inner peripheral surface as the identification signal, an illuminance sensor group that outputs a signal corresponding to the illuminance as the identification signal, and The cutting edge penetration width measuring device according to claim 1 or 2, which includes at least two of a group of temperature sensors that output a signal corresponding to the temperature as the identification signal. The sensor unit includes the pressure sensor group and the illuminance sensor group.
The pressure sensor group is provided at a lower portion in the vertical direction on the inner peripheral surface.
The blade edge portion penetration width measuring device according to claim 4, wherein the illuminance sensor group is provided at an upper portion in the vertical direction on the inner peripheral surface. The sensor unit includes the pressure sensor group and the temperature sensor group.
The pressure sensor group is provided at a lower portion in the vertical direction on the inner peripheral surface.
The blade edge penetration width measuring device according to claim 4, wherein the temperature sensor group is provided at an upper portion in the vertical direction on the inner peripheral surface. While adjusting the excavation amount of the ground below the blade edge portion by using the measurement result of the blade edge portion penetration width measuring device according to any one of claims 1 to 6, the caisson is used as the ground of the ground. A caisson subsidence method in which the surface is submerged to a predetermined depth.

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