JP2835263B2 - Resistor intrusion type ground exploration device and method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to ground exploration in which ground information is obtained by injecting a resistor into the ground to obtain ground information.・ By sequentially adding impact penetration, etc.,
The present invention relates to a simple portable device and a method capable of detecting with high accuracy from soft ground to hard ground.

[0002]

2. Description of the Related Art Among conventional in-situ ground survey methods, a method for obtaining ground information by penetrating a resistor into the ground is currently most frequently used in a standard penetration test by Japanese Industrial Standard J.
This exploration method records the number of hits when hitting with a specified energy per hit to penetrate a sampler, which is a resistor, into the ground to a specified depth, and records the number of hits of the ground sample. The sampling is used together.

[0003] According to the Dutch double pipe cone penetration test method of JIS A1220 standard, a cone, which is a resistor, is moved at a rate of 1 per second.
It records the resistance load when statically penetrating into the ground at a speed of cm.For medium to hard soil, it is necessary to install an anchor for the penetrating load in the ground or prepare a separate reaction force load .

According to the Swedish sounding test method of JIS A1221 standard, as shown in FIG. 1, a resistor consisting of a screw point (5) is connected to a rod (4) and a clamp (3) for loading. Record the depth of penetration with 6 types of weights (2), including 10kg 2 pieces and 25kg 3 pieces including 5kg weight, maximum weight 100k
When the subsidence stops at g, the handle penetrates using the handle (1) connected to the upper end of the rod and records the number of revolutions for the specified penetration amount. The screw point (5) is obtained by twisting a square pyramid-shaped steel material once in its entire length as shown in FIG.

[0005] As described above, the conventional typical ground exploration method is a standard penetration test method based on the impact penetration method, a Dutch double pipe cone penetration test for recording the load when the resistance body is penetrated while controlling the speed. The method consists of Swedish sounding, in which the amount of penetration by six types of loads and the maximum load are applied by applying a rotational force to penetrate.

[0006]

Problems with the prior art are as follows.
In a standard penetration test for obtaining ground information from the number of hits by hitting and penetrating a resistor sampler, the range of ground that can be measured in principle is wide, but the measurement accuracy is poor. In particular, on soft ground, the number of hits is several times or less than one, which is extremely poor. This type of test includes a simpler dynamic cone penetration test and a large-scale dynamic penetration test for gravel ground, which also collects samples as well as the standard penetration test, but has the same problems as the standard penetration test. is there.

The penetration speed control type cone penetration test method is a method for obtaining ground information from a penetration load, and a typical method is a Dutch double tube cone penetration test method. This method enables high precision exploration from soft ground to medium hard ground by controlling the penetration rate to be constant. However, medium-hard ground requires a large intrusion reaction force, and in the case of a topsoil layer where it is difficult to install a screw anchor, etc. There's a problem. Various methods, such as an electric cone and a three-component cone, have been developed for this type of test method, but there is a similar problem since the method is a method of statically injecting the cone without rotating. Although there is a drawback in that it is difficult to determine the soil due to the inability to collect a sample, recent three-component cones can be distinguished to some extent from three types of measured values.

There is a Swedish sounding method as a method of measuring the penetration amount under a constant load using a six-stage weight and obtaining ground information from the number of revolutions by penetrating with a maximum load and rotational force. This exploration method has an advantage that a large reaction force device is not required, but the accuracy is extremely poor because the load is six steps on soft ground. The medium to hard ground has poor rotation efficiency and therefore has a very low penetrating ability, and has a basic defect that the screw point hits a rubble or the like and turns idle and cannot penetrate with rotational force. In addition, since it is performed manually, there is an artificial error, the exploration efficiency is poor, and the exploration depth is shallow. Another drawback is that soil classification is ambiguous because sampling is not possible at present.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to solve the problems of the prior art as shown in the following five items. 1. To enable high-precision exploration even on soft ground. 2. Enhance penetration ability in medium-hard ground, and have sufficient penetration ability for investigation of support layer of pile foundation. 3. Methods and equipment that do not require installation of screw anchors or transportation of large weights as a penetrating reaction force. 4. To be able to collect ground samples while exploring as necessary so that the soil quality of the exploration ground can be determined. 5. Automated methods for obtaining various types of kanji and their combinations, exploration control and recording, eliminating human errors, expanding the measurement range, and achieving high efficiency.

The means for solving the above problems will be described below. The present invention relates to an exploration method and an apparatus mainly aimed at obtaining ground strength information from resistance when a screw-shaped resistor penetrates into the ground, and forcing a rotational torque to the resistor in a soft stratum. By applying a method that penetrates at a constant speed without giving it, it is possible to obtain a highly accurate relationship between the penetrating load and the penetration depth. In this method, a constant speed penetrates by applying a rotational force, and ground strength information is obtained from the rotational speed and the torque. Here, it is characterized in that no special reaction force is required by setting the set upper limit penetration load to a load within a sufficient range by the reaction force of the device's own weight or the device's own weight and the subject's weight.

Further, according to the present invention, in the above-mentioned method, in a hard formation which cannot penetrate even if the rotational speed reaches the set upper limit,
It is characterized in that the penetration ability is enhanced by adding a vibration / impact load.

FIG. 3 is a flowchart showing the above-described search method. First, in starts exploration, penetration speed V as shown in to adjust the penetration load P to be the set value V _0. In this case, it is also possible to prevent the screw point from rotating spontaneously due to the penetration without forcibly applying a rotational force, and the measured torque T = 0.
In 2 If penetration load P is smaller than the set upper limit load P ₀
Continued penetration in the conditions, to change the conditions in Once penetration load P reaches the set upper limit load P _0. Penetrates while adjusting the rotation speed R so as to be V ₀ and P ₀ . Setting conditions of the but is executed as if Re is satisfied, does not give forcibly rotating force to penetrate the setting penetration velocity V ₀ (R
If <R ₀ , T = 0), and the soft ground is such that the intrusion load P is equal to or less than the set upper limit load P ₀ , it is changed . Oppose penetration resistance is large, transmural penetration speed V is at a set penetration velocity V ₀
Input load P is set limit load _{P 0,} and the rotational speed R及
And / or rotation torque T
If the rotational speed is greater than the rotational speed limit R ₀ and the set upper limit torque T ₀ , the condition is changed to: In, the conditions of the penetration load P, the rotation speed R, and the torque T are set in order to penetrate at the set penetration speed, and a vibration / impact load is further applied. In a normal ground, P = P ₀ and T = 0, and when the penetration speed becomes slow, the penetration is made at V ₀ together with the rotational penetration. In penetration velocity V When becomes difficult smaller it becomes intrusive than V _0, to discontinue For example, if halved.

According to the above-mentioned method, it is possible to obtain ground information with the same accuracy as in the static cone penetration test in a soft stratum. Further, by automating the constant-speed penetration by changing the rotation speed in the middle hard formation, it is possible to perform a more reliable and more accurate exploration than the Swedish sounding. This method is characterized by developing a static cone penetration test automatic device with a small reaction force and a Swedish sounding automatic device, respectively, and by integrating them, a synergistic effect of both advantages can be expected.

FIG. 4 is a side view of the main device, in which a pulley (7) connected to a rod rotating motor (6) and a torque transmitting pulley (11) having a hole through a rod (not shown) are shown. The torque is transmitted by a belt that is not provided. An automatic clamp (10) with a built-in load meter / torque meter (not shown) for measuring the penetrating load and torque of the rod is fastened to the center of the torque transmitting pulley (11). The vertical vibration transmitter (12) is connected to the lower surface of the rotational force transmitting pulley (11) and has a structure in which vibration is transmitted in the vertical direction but rotational force is not transmitted.

In addition, a pulley (17) connected to the up / down motor (16) and a pair of right and left rotational force transmitting pulleys (18) as viewed from the front.
Is designed so that the rotational force is transmitted by a belt (not shown). The operation of the motor rotates the two torque transmitting pulleys (18), and the pair of rotary screw posts (14) tightly connected thereto rotates. Further, a pair of nuts (not shown) respectively set on the screw posts are tightly connected to the vertical movement device storage box (8), so that the box moves vertically, and as a result, a rod (not shown) Will be carried out and withdrawn. The reaction force due to the penetration of the rod is the weight of the device including the pedestal (19) shown and the scaffold for the measurer (15)
The upper limit of the measurer's weight (not shown) can be used. The screw supports (9) and (21) fix the horizontal and axial movements of the rotary support (14) and support it in a freely rotatable state. The safety sensor (20) is a safety device that is activated when the pedestal (19) cannot fully withstand the penetration and the rotational reaction force and is displaced relative to the ground. The slide guide and support (13) is for transmitting the pushing reaction force and the torsional reaction force to the pedestal (19).

When it is necessary to determine the soil quality of the exploration ground,
By using a hollow screw-shaped resistor, it was possible to collect ground samples while measuring the penetration resistance. The inner diameter of the hollow portion is the same as the inner diameter of the rod, but the tip is smaller than the inner diameter of the rod to prevent the sample from dropping off.

FIG. 5 shows a resistor sampler (23) having the same shape as the screw point (5) of JIS A1221 standard shown in FIG. Consists of

[0018]

[Function] As described above, the penetration method of the resistive element is improved according to the hardness of the ground in order from the static penetration, the rotation penetration, the vibration / impact penetration, and the penetration ability is improved with high precision. I was able to. In addition, by automating the above-mentioned various penetration methods, their combination control, and measurement / recording, it has become possible to save labor and achieve highly efficient and highly accurate exploration.
Furthermore, the adoption of a hollow resistor made it possible to collect samples for soil determination at the same time as exploration.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A practical test method will be described with reference to the search flowchart of FIG.

The set value of the penetration speed V is set to V ₀ = 1 cm / s, which is the same as the ordinary static cone penetration test guideline. The set upper limit of the penetration load P is the same as JIS A1211 standard. P ₀ = 100k
g. The rotation speed R is set at the upper limit value R ₀ = 120 rpm.
However, since the vibration of the device was large, it was reset to 60 rpm. The set upper limit value of the torque T was set to T ₀ = 50 kg-m from the capacity of the drive motor.

The exploration ground has a hard topsoil layer and a soft viscous land layer with a thickness of less than 10 m, under which there is a medium to dense sand layer, and using the apparatus shown in FIG. 4 according to the flowchart of FIG. Carried out. In the topsoil layer, the rubble hit the rubble and stopped. The rotation speed increased and reached the set upper limit, but the torque was very small. This is because it hit the gravel and cannot be penetrated by the normal loading rotation penetration method. So P = 100kg
When vibration was applied in the loaded state, it started to penetrate, so it switched to the normal search method and restarted. As a result, up to a depth of 10.3 m, the penetration was made at T = 0, but the result that the penetration resistance became considerably large in the depth direction was obtained. However, every time a 1m long rod was added, the resistance was measured when the rod was rotated very slowly at 1 rpm with the lifting load of its own weight underwater, and the frictional resistance of the rod was corrected from this. However, the penetration resistance increased only about 30 kgf per 10 m depth. In the sand layer below this, a state of rotation intrusion was achieved, and the converted number of rotations per m of the penetration amount was 100 to 300 times.

The search control and recording were performed using a personal computer. Servo motors were used for the penetration and rotation motors shown in FIG. 4, and strain gauge type sensors were used for the torque meter and load meter. The total weight of the penetrating device shown in FIG. 4 was 76 kg, including the weight of the measurer, which was about 140 kg. In the sand layer, the rotational torque became large, the pedestal (19) moved, the safety sensor was activated, and the operation stopped automatically.

[0023]

According to the conventional Swedish sounding method, the strength information of the soft ground can be obtained only in six steps. However, in the present invention, the strength can be measured with the same accuracy as the static cone penetration test. did it. On medium to hard grounds, unlike the conventional method, it is possible to reliably search at a penetration speed of 1 cm per second, so that it can be performed in a fraction of the time required by the conventional method. In particular, the penetration capacity of the ground with high penetration resistance was several times greater than that of the conventional rotary penetration method using human power, and the exploration efficiency was more than 10 times. Since the entire exploration system was automated, two workers for lifting and lowering the weight of 100 kg and rotating press-fitting were conventionally used, and one recording operator
What was done manually can now be done by one person. In addition, what has been conventionally determined empirically from the crushing sound at the time of intrusion can now be distinguished by observing the collected sample.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an outline of an entire apparatus based on JIS A1221 standard which is a conventional search method.

FIG. 2 is a side view showing a screw point which is a part of the apparatus of FIG. 1;

FIG. 3 is a flowchart showing a typical procedure of the search method of the present invention.

FIG. 4 is an explanatory view of a penetration device of the present invention.

FIG. 5 is a side view of a hollow resistor sampler.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Handle 2 Weight 3 Loading clamp 4 Rod 5 Screw point 6 Rod rotation rotor 7 Pulley 8 Vertical motion equipment storage box 9 Screw receiver 10 Automatic clamp with built-in load meter / torque meter 11 Rotary force transmission pulley 12 Vertical vibration generator 13 Thrust guide and column 14 Rotating screw column 15 Scaffold for measuring person 16 Motor for vertical movement 17 Pulley 18 Pulley for transmitting torque 19 Pedestal 20 Safety sensor 21 Screw holder 22 Rod 23 Hollow resistor sampler

Claims (7)

(57) [Claims] 1. A screw post rotated by a driving device is mounted on a base.
Stand up, have a ground penetrating resistor at the lower end, and
A drive device for rotating the rod to which the lucometer is attached is built-in and
And a device storage box which is screwed up and down
The rod measured with a load meter using the total device load as the reaction force
When the penetration load reaches the set maximum penetration load, the rod penetrates at the set penetration speed.If the penetration does not occur at the set penetration speed even when the set maximum penetration load is reached, the rod is rotationally driven with the set penetration load applied. Resistor intrusion type ground surveying device characterized by penetrating through. 2. The device according to claim 1, wherein the rod is penetrated.
A device that applies additional vibration and impact loads to the equipment storage box
If the set penetration speed is not applied to the rod even if the set upper limit penetration load and the set upper limit rotation speed or the set upper limit torque are applied to the rod, a vibration / impact load of the rod is further applied. Ground exploration equipment. 3. The ground exploration apparatus according to claim 1, wherein the ground penetrating resistor is a hollow screw-shaped resistor , which can measure the penetrating resistance and collect a ground sample. 4. The ground exploration apparatus according to claim 1, wherein control and recording of penetration resistance, rotation speed, vibration / impact load, penetration amount, and the like are automated. 5. A rod having a ground penetrating resistor connected to a lower end thereof.
To the rod by continuously applying a penetration load due to the reaction force of the device.
At the set penetration speed to obtain ground strength information,
Even if the penetration load rises and reaches the set upper limit penetration load, the set penetration
When the rod does not penetrate at the penetration speed, the rod is subjected to a further rotational force while applying the set upper limit penetration load to penetrate the rod, and from the rotational torque, or the number of rotations per unit penetration amount, or from both, Ground exploration method characterized by obtaining information such as strength constants. 6. The method according to claim 5, wherein the rod does not penetrate at the set upper limit penetration speed even when the set upper limit rotational speed is reached while the set upper limit penetration load is applied to the rod.
If the set upper limit penetration speed does not penetrate at the set upper limit penetration speed even when the set upper limit torque is reached with the set upper limit penetration load applied, or
When both of these conditions are satisfied, in addition to the set upper limit penetration load and the set upper limit rotational force, the rod is further subjected to the set vibration and impact load to penetrate at the set penetration speed, and the rotation speed is used to determine the strength constant of the ground. A ground exploration method comprising: obtaining information and obtaining information such as a ground strength constant from a penetration speed after reaching a set upper limit rotational speed or a set upper limit torque. 7. The measured resistance value selected by the method according to claim 5 or 6 is corrected by rotating the rod without applying a load to the penetrating resistor to obtain the relationship between the rotational speed and the rotational resistance. Ground exploration method.