JP5041301B2 - Ground survey method, ground survey verification apparatus, and ground survey verification method - Google Patents

Description

  The present invention relates to a ground survey method for evaluating soil quality in a stratified structure of a ground or a slope, a ground survey verification apparatus and a ground survey verification method for verifying a result of the ground survey.

  Conventionally, as a ground survey device that evaluates the possibility of landslide that occurs when there is a lot of rainfall, soil (sample) collected by boring the ground is set in a triaxial compression device, and the sample is subjected to a predetermined condition. The current situation is to evaluate the ground from which the sample is collected by evaluating the sample against the landslide from the stress that causes deformation of the sample by compressing from three axes, that is, axial direction and radial direction, respectively. .

  As this triaxial compression device, for example, a cylindrical body in which both upper and lower openings are sealed with disk-shaped upper and lower lids and a pressure chamber is formed inside, and a sample (soil collected from the field) A mounting table having an inclined surface for mounting the upper surface, a loading device that generates stress in the axial direction via a piston penetrating through the center of the upper lid, and a load of the loading device on the piston. A measuring device for measuring, a pressure supply device for generating a stress in a lateral direction in the pressure chamber, and a pore water pressure measuring device for measuring a pressure related to pore water discharged through a groove formed in the mounting table. What is provided is known (see Patent Document 1).

  The mounting table is made of a rigid body (aluminum), and the inclined surface described above is used for evaluating landslide, and the lower surface of the sample is also inclined according to the inclination angle of the inclined surface. . The sample is placed in a state where the inclined surface of the sample is joined to the inclined surface of the mounting table. Further, as described above, the mounting table has a plurality of grooves formed from the bottom surface to the outer peripheral surface. The grooves are formed in a radial shape so that the center of the bottom surface is a confluence, and are formed in parallel to the outer peripheral surface along the axis. The sample is formed with the bottom surface inclined so as to correspond to the inclined surface of the mounting table, and the outer peripheral surface is covered with filter paper and rubber.

  In the triaxial compression device configured as described above, the pressure chamber is filled with water, and a pressure is applied in the lateral direction by the pressure supply device to form a sample compaction state. Under this compaction situation, axial pressure is applied by the loading device, and the temporal changes in axial and lateral stress and pore water pressure are represented in an effective stress path diagram. Then, the landslide of the target ground is evaluated using this effective stress path diagram. That is, when the mounting table is not used, the tilting surface of the mounting table is 60 degrees, and the tilting surface of the mounting table is 45 degrees, the tilting point is connected at the bending point when the pore water pressure is maximum. A line is drawn, and the inclination angle of the inclined line is taken as the strength against landslide.

  A Swedish sounding test apparatus is generally known as a means for measuring the support strength of the ground. This device is provided with a resistor called a screw point in the shape of a drill blade at the tip of the rod, and the rod is pushed vertically with respect to the ground and rotated while a weight is placed on the rod. The soil is penetrated into the ground, and the hardness of the ground is investigated while measuring the resistance when the screw point rotates with respect to the ground and the amount of penetration of the rod. As this type of device, there is known a device for improving work efficiency at the time of penetrating a rod by sequentially applying a plurality of predetermined pressures set in a fluid pressure cylinder to the rod (see Patent Document 2).

JP 2009-53042 A JP-A-10-121453

  However, in the case of the ground survey method using the triaxial compression device, the soil (sample) collected from the field is being evaluated using the triaxial compression device under the prescribed test conditions. There is a problem that evaluation in the structure, for example, evaluation for landslide is not sufficient.

  In addition, in the case of Swedish sounding test equipment, although it is conducted at the site where the building is constructed, there is no means to conduct a thorough investigation on the stratified structure of the ground. There is a problem that a good evaluation cannot be obtained.

  In view of the above problems, an object of the present invention is to provide a ground survey method, a ground survey verification device, and a ground survey verification method capable of accurately evaluating the soil or slope soil.

  In the ground investigation device according to the present invention, when screw points 21, 21A, 21B, and 21C that are thrust at right angles to the ground are started to penetrate, and screw points 21 that are penetrated with a predetermined weight while rotating at low speed. , 21A, 21B, 21C, when the descent time of the rods 20, 20A, 20B, 20C is faster than the predetermined time, the load applied to the rods 20, 20A, 20B, 20C is offset by the fluid pressure and adjusted only to the own weight of the rods 20, 20A, 20B, 20C. After that, when the fluid pressure is gradually applied to the rods 20, 20A, 20B, and 20C to return to the predetermined weight, the screw points 21, 21A, and the rods (20, 20A, 20B, and 20C) are rotated at a low speed again. The rods 20, 20A, 20B, and 20C that are penetrated with a predetermined weight while being rotated at a low speed while penetrating 21B and 21C. On the other hand, when the screw points 21, 21A, 21B, and 21C continue to be stopped even if the prescribed maximum weight is applied, the rods 20, 20A, 20B, and 20C in the state in which the maximum weight is applied are rotated at a high speed. It is a ground survey method for surveying the ground using a ground survey device that penetrates the screw points 21, 21A, 21B, 21C, and is set assuming a sand layer and a load set assuming a clay layer in the ground. While a load smaller than the above load is applied to the screw points 21, 21A, 21B, 21C, the first and second measurement points separated by about 1 to 2 m are penetrated while rotating at a rotation speed of 30 rotations per minute or less. The first and second measurement locations are applied to the concrete drill bit 210 attached to the tip of the rod 200 with a load set in accordance with Further, the measurement data at the first to third measurement points are shown in the chart while being rotated while rotating at a rotation speed of 30 rpm or less to a third measurement point that is further 1 to 2 m away from .

  In this case, when the measurement data at the first to third measurement points are shown in the chart, in the case of the concrete drill bit 210, data in a level state with almost no change is obtained, but assuming a clay layer and a sand layer In the case of the screw points 21, 21A, 21B, and 21C to which the set load is applied, when the moisture is included, the data is greatly opened. That is, it is possible to determine whether or not moisture is contained in the soil at each measurement point. That is, it can be estimated whether or not the ground at each measurement point is a ground where landslide is likely to occur.

  Moreover, according to this invention, it is preferable that the load set supposing a clay layer shall be 1000N-2500N, and the load set supposing a sand layer shall be 300N-1000N.

  In this case, data that could not be obtained with only the load (1000 N) specified by the Ministry of Land, Infrastructure, and Soil It is possible to obtain data that is presumed to exist. That is, data according to the soil of the ground can be obtained.

  A ground survey verification apparatus according to the present invention is a ground survey verification apparatus used when verifying a ground survey result, wherein a screw point 21A is attached to a tip portion and soil water is allowed to flow into the tip portion. Cylindrical rod 20A in which inflow hole 51 is formed, and an annular bag in which open end portions on both sides are fixed to the outer peripheral surface of rod 20A above the inflow hole 51 and bulges by the supply of fluid A body 55, fluid pressure supply means 60 for supplying fluid to the bag body 55, water absorption means for sucking up water that has flowed into the rod 20A from the inflow hole 51, and inside the rod 20A. It is characterized by comprising a water level detecting means 70 for detecting the water level flowing into the inside and an inflow time detecting means for detecting the inflow time of the water flowing into the rod 20A.

  In this case, in order to verify the ground survey result, the screw point 21A attached to the tip of the rod 20A is penetrated into the penetration hole G formed at the time of the survey, and the fluid is supplied to the bag body 55. The outer surface of the bag body 55 is pressed against the inner wall of the penetration hole G. That is, the inflow of water from above the bag body 55 is prevented, and the water inflow path is made one. In this state, the soil water is caused to flow into the rod 20A from the inflow hole 51 formed at the tip of the rod 20A. Then, the water that has flowed in is temporarily absorbed, and the inflow time and the water level of the water that flows in from the inflow hole 51 are detected again, thereby verifying the correctness of the investigation result. That is, if the inflow time of water is fast and the water level is high, the above-described survey results are correct.

  The ground survey verification method according to the present invention is a ground survey result verification method for verifying a ground survey result using the ground survey verification device, and after the ground survey is completed, it is estimated that there is a lot of moisture depending on the result of the ground survey. The screw point 21A provided with an annular bag body 55 that bulges by supply of fluid is inserted into the position of the soil, and at this position, fluid is supplied to the bag body 55 so that the bag body 55 is moved radially outward. It is expanded and pressed against the inner wall of the penetration hole G formed at the time of the ground investigation. After sucking up the soil water flowing into the rod 20A from the inflow hole 51 of the rod 20A, it flows again into the rod 20A from the inflow hole 51. It is characterized in that the inflow time and the water level of the water to be detected are detected.

  In this case, by detecting the inflow time and the water level of the water flowing again into the rod 20A at the position where it is estimated that the soil is viscous but contains a lot of water. The survey results can be verified.

  As described above, according to the present invention, the load related to the screw point is set on the assumption of the clay layer and the sand layer while rotating the rod at a low speed, so that the stratified structure of the ground or the slope can be accurately determined. As well as being able to grasp, it is possible to easily detect whether the ground is prone to landslide.

The side view which shows the ground investigation apparatus which concerns on one Embodiment of this invention. The front view of FIG. The rear view of FIG. The top view of FIG. (A) is sectional drawing which shows the rod to which the screw point was attached, (b) is sectional drawing which shows the rod to which the drill bit for concrete was attached. Operation | movement explanatory drawing of the ground investigation apparatus of FIG. The flowchart of the ground investigation apparatus of FIG. Sectional drawing which shows the rod provided with the water level detector and annular bag which comprise a part of ground investigation verification apparatus. Schematic which shows the state which the bag body of FIG. 8 expanded by supply of the fluid, and was press-contacted to the inner wall of the penetration hole. Sectional drawing which shows the rod provided with the sampler. Sectional drawing which shows the rod by which the moisture detector was equipped internally.

Hereinafter, a ground survey method according to an embodiment of the present invention will be described with reference to FIGS.
First, before explaining the ground survey method according to the present embodiment, a ground survey device used in the ground survey method will be described with reference to FIGS. The ground surveying apparatus includes a gantry 1 configured to be movable, a vertically long frame 5 standing on the gantry 1, a movable body 10 provided on the frame 5 so as to be movable up and down, and a frame. 5, a cylinder 15 attached to 5, a weighting means B for supplying fluid pressure to the cylinder 15, a moving means C for moving the moving body 10 attached to the cylinder 15 up and down, and a moving body 10. Further, the rod 20 having the screw point 21 attached to the tip, the rod 200 having the concrete drill bit 210 attached to the tip, and the turning means for turning one of the rods 20 and 200. D, and a weighting means B, a moving means C, and a control means E for controlling the rotating means D. The support means A is composed of a connecting portion with the gantry 1, the frame body 5, the moving body 10, and a rotation shaft of a motor 40 described later.

  As shown in FIGS. 1 to 4, the gantry 1 is composed of a trolley having a rectangular shape in plan view with wheels 2 provided at the front and rear, and is configured to be detachable from a lower frame 7 (not shown). )

  As shown in FIGS. 1 to 3, the frame 5 has an upper frame 6 and a lower frame 7 in a substantially square shape in plan view, and the upper end is welded to both the left and right sides of the upper frame 6, and the lower end is A pair of left and right side columns 8 welded to the left and right sides of the lower frame 7, and a rear column 9 having an upper end welded to the rear portion of the upper frame 6 and a lower end portion welded to the rear portion of the lower frame 7. It has.

  As shown in FIGS. 1 to 4, the moving body 10 has a U-shape in a side view, and has a rectangular base portion 11 that is connected to each ring of a part of a chain 19 described later, and the base portion 11. And a bent portion 12 bent in the horizontal direction from the upper end portion and the lower end portion. The moving body 10 is attached with a motor (rotating means) 40 for rotating the rods 20 and 200 to the lower bent portion 12 following the movement of the chain 19.

  As shown in FIG. 6, the cylinder 15 is composed of two chambers, an oil storage chamber 16 and an air storage chamber 17, and the telescopic rod 18 penetrates in the vertical direction, as shown in FIGS. 1 to 4. A support plate 22 is attached to each of the upper end portion and the lower end portion of the telescopic rod 18, and a sprocket 23 is rotatably provided on the support plate 22. An annular chain 19 is wound around the sprockets 23, and the base of the moving body 10 is fixed to the chain 19.

  As shown in FIGS. 1 to 4 and 6, the weighting means B contains a predetermined amount of oil inside, a tank 25 that supplies either oil or air to the cylinder 15, and air to the tank 25. A compressor 26 to be supplied; a regulator 27 for adjusting the pressure of the compressor 26; a tank 25 and a cylinder 15; a pair of three-way valves 28a and 28b for switching the fluid pressure of the tank 25 and the cylinder 15; 25, a needle valve 29 and a two-way valve 30 provided on the downstream side. 1 to 4, the compressor 26 and the regulator 27 are not shown, but are omitted because a commercially available product is separately carried into the work site.

  As shown in FIGS. 1 to 4, the moving means C is installed on the left and right side columns 8 on the rails 35 provided along the length direction, and on the upper and lower bent portions 12 of the moving body 10. And a plurality of rollers 37 that are rotatably attached to the upper and lower portions of the support plate 36 and slide on the rail 35.

  As shown in FIG. 5 (a), the rod 20 includes an excavation rod 20a provided with a screw point 21 at the tip, and a plurality of connecting rods 20b connected to the excavation rod 20a at a predetermined lowered position. It is composed of Further, as shown in FIG. 5B, the rod 200 includes a drilling rod 200a to which a concrete drill bit 210 is attached and a plurality of connecting rods 200b connected to the drilling rod 200a at a predetermined lowered position. It consists of and.

  As shown in FIGS. 1 to 4, the rotating means D includes a base end portion of the vertical rod 20, a rotation shaft of the motor 40 led out in the horizontal direction, and a gear box (deceleration) provided in the motor 40. (Mechanism part) 41, the base end part of the rod 20, the rotating shaft of the motor 40, the collet which connects the gear box 41, and the detector which detects the rotation speed of the rod 20 (not shown) are provided.

  The control means E is equipped with a microcomputer and displays a descending distance (penetration depth), a descending time, a rotational speed of the motor 40 (rod 20), and a soil hardness (N value) in a chart form. And is attached to the frame 5. The compressor 26, the regulator 27, the three-way valves 28a and 28b, the needle valve 29, the two-way valve 30, and the motor 40 are programmed to operate according to the flow of FIG.

Here, when the screw point 21 penetrates into the ground, for example, if it is a space layer, the N value indicates 0 to 3, and if it is a soft layer (sand layer), the N value indicates 6 or less. The diameter of the screw point 21 is, for example, 20 to 40 mm, the diameter of the concrete drill bit 210 is, for example, 22 mm to 35 mm, the air pressure of the compressor 26 is 6 to 7 kg / m ² , the connecting rods 20b and 200b, and the drilling The force for pulling out the rods 20a, 200a from the ground is 1.5 tons.

  In addition, when the descent time of the screw point 21 becomes faster than a predetermined time, the reason why the load applied to the rod 20 is canceled by the fluid pressure and only the dead weight of the rod 20 is used is that the screw point 21 penetrates. Even if the strata are soft, such as sand, earth, and gravel, they do not penetrate through these strata and reach hard rock and clay layers all at once. This is to detect if there is.

  The reason why the screw point 21 is penetrated at a low rotation, that is, 30 revolutions per minute is to infer the formation of the penetration site. That is, if the load is large and the rotational speed is increased, there is a possibility of passing through soft soil such as a sand layer. Therefore, it is preferable to set the rotation speed so that the resistance of water and the resistance due to the viscosity of the soil can be felt as much as possible.

  The reason why the load applied to the screw point 21 is set assuming the clay layer and the sand layer is that different data can be obtained when the soil contains moisture and when the soil does not. More specifically, when a load set on the assumption of a clay layer is applied to the screw point 21 while rotating at a rotation speed of 30 rotations per minute or less, the clay layer containing moisture contains moisture. It takes a little more time compared to a clay layer that is not. On the other hand, since the load is large, the sand layer passes without taking time. In addition, when a load set assuming a sand layer, that is, a load smaller than a load set assuming a clay layer is applied to the screw point 21 while being rotated at a rotation speed of 30 rotations per minute or less, moisture is included. In the case of the clay layer, since the load is small and the rotational speed is low, it takes a long time for the screw point 21 to penetrate. On the other hand, since the load is set on the sand layer assuming the sand layer, resistance occurs when penetrating. In other words, it is possible to detect the sand layer that has passed under the load set assuming the clay layer. Furthermore, when a load set on the assumption of the clay layer is applied to the concrete drill bit 210, the concrete drill bit 210 reaches the hard rock layer from the sand layer without receiving water resistance. That is, the concrete drill bit 210 is suitable for detecting hard soil.

  Next, a ground survey method using the ground survey device according to the present embodiment will be described with reference to FIGS. 5 and 6 and Table 1. FIG.

  Here, the control flow of the ground investigation device will be described taking the rod 20 as an example. First, at the point where the descending distance is 0 cm, the flow path between a and b of one of the three-way valves 28a is opened, and the flow path between a and c of the other three-way valve 28b is released to the atmosphere. Air pressure is supplied, oil is supplied to the cylinder 15 via the needle valve 29 and the two-way valve 30, and the air pressure in the air storage chamber 17 of the cylinder 15 is reduced by 0.5 (S1). The numerical value of the air pressure corresponds to the weight of the motor 40 and the moving body 10, and since the weight is reduced, the weight applied to the rod 20 becomes “0”, and the rod 20 is not lowered and is stopped (hereinafter referred to as a standby state). It becomes).

  Simultaneously with the depressurization of the air chamber 17, the descent distance of the rod 20 is measured (S4), and the measurement of the descent time of the rod 20 is started (S5). The descending distance is determined by measuring the distance descending from the starting position with the center position of the lower sprocket 23 where the rod 20 is raised as the starting position. On the other hand, as for the descent time, the proximity switch S is turned on every time each ring of the chain 19 passes the detection unit of the proximity switch S. The speed of this on-on period is converted as the descent time.

  At the point of a descent distance of 20 cm, the flow path between a and b of one three-way valve 28a is closed, the flow path between a and c of the other three-way valve 28b is opened, and air pressure is supplied to the air accommodating chamber 17. Then, the oil in the cylinder 15 is returned to the tank 25 through the two-way valve 30 and the needle valve 29, the flow path between a and b of the other three-way valve 28 is closed, and the air pressure in the cylinder 15 is restored. (S2). That is, the weight (450 W) of the motor 40 and the moving body 10 is applied to the rod 20.

  In the section with a descending distance of 20 to 40 cm, the opening of the flow path between a and c of one three-way valve 28a is maintained, and the closing of the flow path between a and b of the other three-way valve 28b is maintained, At the same time as the air pressure in the cylinder 15 is gradually increased (S3), the rod 20 is rotated at a low speed, that is, 30 rpm or less (S8), and the rod 20 is inserted in response to the pressurization.

  Further, for example, when the screw point 21 reaches the water permeable layer such as sand, gravel, and soil by further penetration, the descent time of the rod 20 becomes faster than the predetermined time (S6), and the operations of S1 to S3 described above are repeated. At the same time, the low rotation of the rod 20 is maintained. The reason for this is to prevent the screw point 21 from penetrating through the soft water-permeable layer and reaching the water-impermeable layer such as the bedrock or the viscous layer below it. Or it is for confirming whether water permeates and it is in a mud state.

  For example, when the screw point 21 reaches the clay layer (impermeable layer), the screw point 21 is in a stopped state even if the load applied to the rod 20 applies a prescribed maximum load (S9). That is, this stop is performed when the rotation of the screw point 21 is stopped, or when the stop time when the descent of the rod 20 is stopped is determined to be longer than the predetermined time (S7), and the rotation speed of the rod 20 is set. The screw point 21 is penetrated by gradually raising (S10). If it is determined that the stop time of the rod 2 is longer than the predetermined time (S7) and it is determined that the subsequent penetration is impossible, the rod 20 is pulled out from the ground and the operation is completed. . In other words, if the screw point 21 does not penetrate even if the rod 20 is rotated with the maximum load applied, it indicates that the rod 20 is impermeable layer thereafter, and if landslide occurs before this impermeable layer. It can be inferred that there is a boundary layer.

(Example)
Next, examples will be described. Based on the control flow described above, measurement is performed at each of the first to third measurement points on the ground where the building is constructed. First, at a first measurement point, a load 1000N to 2500N (preferably 1200N) set on the assumption of a clay layer is applied to the screw point 21, and the screw point 21 is penetrated while rotating at a rotation speed of 30 rotations per minute or less. In addition, at a second measurement point that is about 1 to 2 m away from the first measurement point, a load of 300N to less than 1000N (preferably 800N) set assuming a sand layer is applied, and at a rotation speed of 30 rotations per minute or less While being penetrated while rotating, at a third measurement point further about 1 to 2 m away from the first and second measurement points, the rod 200 to which the concrete drill bit 210 was attached was set assuming a clay layer. A load (preferably 1200 N) is applied, and the material is penetrated while rotating at a rotation speed of 30 rotations or less per minute. Then, the measurement data at the first to third measurement points is charted (see Table 1).

  In Table 1, the curve of the screw point 21 with a load of 1200 N is a first curve, the curve of the screw point 21 with a load of 800 N is a second curve, and the curve of the drill bit 210 for concrete is a third curve. And the soil of the point of about 20 cm-30 cm is changing the 3rd curve a little away from these curves so that the 1st and 2nd curves may overlap. Therefore, the soil at this depth is presumed to be a soil with a little moisture and high density. After that, the first curve to the third curve change so as to overlap each other, and at the 90 cm point, the second curve rises, the third curve changes below the second curve, and the first curve changes. It is in a state of being almost flat below the third curve. The soil at this depth is presumed to be a soil with slightly higher moisture and slightly higher density. Since the rod 20 is being replaced at the 100 cm point, the data at this point is ignored. Next, at the point of 100 cm to 130 cm, only the third curve rises rapidly. The soil at this point is presumed to be a highly saturated soil with moisture in a saturated state. Thus, even if it is the soil of the same point, it can understand that a difference arises with the load (a load of 1200N and 800N) concerning the screw point 21. FIG. And the density with respect to a landslide and the intensity | strength of soil are obtained by drawing the inclination line which put the element of time with respect to the 2nd curve which raises.

  Next, verification work for verifying the results obtained by the ground survey apparatus will be described. First, the ground survey verification apparatus used during the verification work will be described. As shown in FIGS. 8 and 9, the ground survey verification apparatus 50 is a cylindrical rod in which a screw point 21 </ b> A is attached to the distal end portion and an inflow hole 51 for allowing soil water to flow into the distal end portion. 20A and an annular bag body 55 swelled by the supply of fluid, with the open ends on both sides being fixed to the outer peripheral surface of the rod 20A above the inflow hole 51, and fluid to the bag body 55 Fluid pressure supply means 60 to supply, water absorption means (not shown) for sucking up the water that has flowed into the rod 20A from the inflow hole 51, and a water level that is provided inside the rod 20A and flows into the inside from the inflow hole 51. A water level detecting means 70 for detecting and an inflow time detecting means for detecting the inflow time of water flowing into the rod 20A are provided.

  The rod 20A has a cylindrical shape, and makes it easy to grasp the moisture state of the soil by allowing the soil water to flow into the rod 20A. Specifically, a detection portion 72 of a water level detection means 70 described later is provided inside, and an air supply pipe 61 of a fluid pressure supply means 60 for supplying air to the bag body 55 is inserted. In addition, the code | symbol 201a in a figure is a rod for excavation, 201b is a rod for connection.

  As shown in FIG. 9, the fluid pressure supply means 60 is connected to a check valve 56 of a bag body 55, which will be described later, and is led out from the end of the rod 20A located on the ground surface through the inside of the rod 20A. The air supply pipe 61 is connected to the other end of the air supply pipe 61 and has a compressor 62 for supplying a fluid (in the present embodiment, air) to the air supply pipe 61 ( (See FIG. 8).

  As shown in FIG. 9, the bag body 55 is made of rubber and is provided with a check valve 56, similar to a bicycle tire, and the check valve 56 is provided with one end connected to the compressor 62. The other end of the trachea 61 is connected. When air is supplied to the bag body 55 through the air supply pipe 61, the bag body 55 swells substantially outward in the radial direction. Specifically, the diameter of the penetration hole G swells larger. When the bag body 55 bulges in the radially outward direction, the outer surface of the bag body 55 bulged on the inner wall of the penetration hole G comes into pressure contact, and one water inflow path is formed.

  Although not shown, the water absorption means includes a commercially available pump and a water absorption pipe connected to the pump. And while inserting a water absorption pipe | tube into the inside of rod 20A, a pump is operated and the water which flowed in the inside of rod 20A is sucked up through a water absorption pipe | tube. At this time, when the water level falls below the detection unit 72 of the lowest level a of the water level detection means 70 to be described later, the light emitting diodes 73,... Corresponding to the lowest level a are turned off and flow into the rod 20A. It is confirmed that water has been sucked up.

  As shown in FIG. 8, the water level detection means 70 inserts the electric wire 71 in which the conductor portion 72a is exposed at each position a to d at a predetermined interval (for example, an interval of 25 cm) into the rod 20A. In addition, light emitting diodes 73 are provided according to the positions a to d. Then, one of the light emitting diodes 73 at each of the positions a to d is turned on and turned on by the level of the water flowing into the inside through the inflow hole 51 of the rod 20A. That is, it becomes possible to grasp the moisture content of the soil by visually recognizing the water level. In other words, the higher the water level, the higher the moisture content of the soil. Reference numeral 74 in the figure denotes a power source that supplies a DC power source to the light emitting diodes 73.

  The inflow time detecting means is incorporated in the control means E of the above-described ground survey device, and functions as a water level meter for detecting the water level, and the time to reach each water level is the ON-ON period of the light emitting diodes 73 at each position. And a warning means for outputting a warning (sound, buzzer, light, etc.) when the highest level light emitting diode 73 is lit quickly. That is, if the lighting time of the light emitting diodes 73,... At each position is earlier, it is considered that the speed of water passing through the soil (water permeability) is faster. Moreover, when it takes time for the highest level light emitting diode 73 to light, it is thought that the speed (water permeability) of the water which passes through the inside of the soil is slow.

  Next, a verification method for verifying the survey results of the ground survey will be described. The investigation result obtained by the ground investigation device, that is, the investigation result presumed to be soil that is viscous but contains a lot of water is verified. First, the screw point 21A is penetrated into the penetration hole G formed at the time of the investigation together with the rod 20A. Subsequently, as shown in FIG. 9, air is supplied to the bag body 55 through the air supply pipe 61, the bag body 55 is expanded, and the outer surface of the bag body 55 is pressed against the inner wall of the penetration hole G. That is, the inflow of water from above the bag body 55 is prevented, and the water inflow path is made one. In this state, the soil water is caused to flow into the rod 20A from the inflow hole 51 formed at the tip of the rod 20A. Then, the water that has flowed in is temporarily absorbed, and the inflow time and the water level of the water that flows in from the inflow hole 51 are detected again, thereby verifying the correctness of the investigation result. In this case, if the inflow time of water is fast and the water level is high, it is judged that the above-mentioned investigation result is correct, and the water permeability state can be grasped.

  In addition, in the said embodiment, although the hardness of the soil which changes according to the penetration depth was shown in Table 1, as shown in Table 2, even if the hardness of the soil which changes according to descent time is made into a chart, Good. In this case, similarly to Table 1, the curve of the screw point 21 with a load of 1200 N is the first curve, the curve of the screw point 21 with a load of 800 N is the second curve, and the curve of the concrete drill bit 210 is the third curve. And And in Table 2, it changes so that the 1st and 3rd curve may overlap, and the 2nd curve changes rapidly according to time.

  Moreover, as shown in Table 3, the penetration depth that changes in accordance with the descent time may be charted. In this case, similarly to Table 1, the curve of the screw point 21 with a load of 1200 N is the first curve, the curve of the screw point 21 with a load of 800 N is the second curve, and the curve of the concrete drill bit 210 is the third curve. And In Table 3, at the point of 100 cm, the first and third curves both show an ascending curve, and the second curve changes so as to be greatly curved.

  In the embodiment, the rods 20 and 200 shown in FIGS. 5A and 5B are used. As other rods, a cylindrical sampler 80 for collecting soil on the ground is provided. The rod 20B to be used or the rod 20C in which the moisture detecting means 90 is provided may be used. As shown in FIG. 10, the sampler 80 includes a cylindrical body 81 in which internal threads 82 are formed on the inner surfaces of both ends, and a through-hole 83 formed in a radially outward direction on the wall surface of the cylindrical body 81. And a covering body 84 that extends in a direction opposite to the rotation direction when penetrating and covers the through-hole 83. Then, the sample collector 80 is inserted into the position of the soil to be collected, and the soil is collected by the covering 84 by rotating the rod 20B in the direction opposite to the rotation direction when penetrating. In the figure, reference numeral 202a is an excavating rod, and 202b is a connecting rod. Further, as shown in FIG. 11, the moisture detection unit 90 includes a sensor 91 provided inside, and a light emitting diode 92 that blinks in response to a detection signal of the sensor 91. Reference numeral 93 shown in the figure is an electric wire connected to the sensor 91, 94 is a power source for supplying DC power to the sensor 91 and the light emitting diode 92, 203a is an excavation rod, and 203b is a connecting rod.

  Moreover, in the case of the said embodiment, although the substantially horizontal ground is made into the investigation object, it cannot be overemphasized that a slope can also be made into the investigation object. However, in this case, it is necessary to attach a support rod capable of supporting the screw point 21 at an angle to the slope so that the screw point 21 can be supported in an oblique state.

  DESCRIPTION OF SYMBOLS 1 ... Mount, 2 ... Wheel, 5 ... Frame, 6 ... Upper frame, 7 ... Lower frame, 8 ... Side support | pillar, 9 ... Rear support | pillar, 10 ... Moving body, 11 ... Base, 12 ... Bending part, 15 ... Cylinder, 16 ... Oil storage chamber, 17 ... Air storage chamber, 18 ... Telescopic rod, 19 ... Chain, 20, 20A, 20B, 20C ... Rod, 20a, 201a, 202a, 203a ... Drilling rod, 20b, 201b, 202b, 203b ... connecting rod, 21 ... screw point, 22 ... support plate, 23 ... sprocket, 25 ... tank, 26 ... compressor, 27 ... regulator, 28 ... three-way valve, 29 ... flow control valve, 30 ... two-way valve , 35 ... rail, 36 ... support plate, 37 ... roller, 40 ... motor, 41 ... gear box, 50 ... ground survey verification device, 51 ... inflow hole, 55 ... bag body, 56 ... check valve, 60 ... fluid pressure Supply means, DESCRIPTION OF SYMBOLS 1 ... Supply pipe, 62 ... Compressor, 70 ... Water level detection means, 71 ... Electric wire, 72 ... Detection part, 72a ... Conductor part, 73, 92 ... Light emitting diode, 80 ... Sampler, 81 ... Cylindrical body, 82 ... Female screw , 83 ... Through-hole, 90 ... Moisture detection means, 91 ... Sensor, 93 ... Electric wire, 74, 94 ... Power supply, A ... Support means, B ... Moving means, C ... Weighting means, D ... Rotating means, E ... Control means , G ... penetration hole, S ... proximity switch.

Claims (4)

  When the screw point (21, 21A, 21B, 21C) thrusting at a right angle with respect to the ground starts to penetrate, and the screw point (21, 21A, 21B, 21C) penetrated with a predetermined weight while rotating at low speed on the ground ) When the descent time of the rod (20, 20A, 20B, 20C) is faster than the predetermined time, the load applied to the rod (20, 20A, 20B, 20C) is canceled by the fluid pressure and adjusted only to the own weight of the rod (20, 20A, 20B, 20C). Thereafter, when the fluid pressure is gradually applied to the rods (20, 20A, 20B, 20C) to return to the predetermined weight, the screw points (21, 20A, 20B, 20C) are rotated again while rotating the rods (20, 20A, 20B, 20C) again. 21A, 21B, and 21C), and a rod (20, 20A, 20B, and 20C) that penetrates with a predetermined weight while rotating at a low speed On the other hand, if the screw point (21, 21A, 21B, 21C) continues to stop even if the specified maximum weight is applied, the rod (20, 20A, 20B, 20C) in a state where the maximum weight is applied is used. A ground surveying method for surveying the ground using a ground surveying device that penetrates screw points (21, 21A, 21B, 21C) while rotating at a high speed. A load smaller than the above load set on the assumption is applied to the screw points (21, 21A, 21B, 21C) and rotated at a rotation speed of 30 rpm or less to the first and second measurement points separated by about 1 to 2 m. The load set according to the clay layer is applied to the concrete drill bit (210) attached to the tip of the rod (200). Then, the measurement data at the first to third measurement points are shown in the chart while rotating at a rotation speed of 30 rpm or less to a third measurement point that is further 1 to 2 m away from the first and second measurement points. A ground survey method characterized by what is shown.   2. The ground survey method according to claim 1, wherein a load set assuming a clay layer is 1000N to 2500N, and a load set assuming a sand layer is 300N to less than 1000N.   A ground survey verification device used for verifying ground survey results, wherein a screw point (21A) is attached to the tip and an inflow hole (51) for allowing soil water to flow into the tip is formed. An annular bag having open end portions on both sides fixed to the outer peripheral surface of the cylindrical rod (20A) and the rod (20A) above the inflow hole (51) and bulging by the supply of fluid A body (55), a fluid pressure supply means (60) for supplying fluid to the bag body (55), a water absorption means for sucking up water that has flowed into the rod (20A) from the inflow hole (51), 20A), a water level detecting means (70) for detecting the water level flowing into the inside from the inflow hole (51), and an inflow time detecting means for detecting the inflow time of the water flowing into the rod (20A). Specially provided Ground survey verification device to.   A ground survey result verification method for verifying a ground survey result using the ground survey verification apparatus according to claim 3, wherein the position of the soil is assumed to be rich in water according to the ground survey result after the ground survey is completed. The screw point (21A) provided with an annular bag body (55) that bulges by the supply of fluid is inserted into the bag body (55) at this position to supply the fluid to the bag body (55). While expanding in the outward direction, it was brought into pressure contact with the inner wall of the penetration hole (G) formed during the ground survey, and the water of the soil flowing into the rod (20A) from the inflow hole (51) of the rod (20A) was sucked up. Then, the verification method of the ground investigation result characterized by detecting the inflow time and the water level of the water which flows in again into the rod (20A) from the inflow hole (51).

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