JPH06336719A - Resistant-penetration type ground tester inspection by use thereof - Google Patents

Abstract

PURPOSE:To investigate various ground from soft ground to hard one with a high accuracy, by penetrating a resistant against penetration into ground and adding penetration means such as static load, roraty movement, vibration, impulse, etc., one by one in accordance with the resistance of penetration. CONSTITUTION:A penetration load is adjusted to bring the penetrating speed close to a preset value and the resistant is penetrated until its penetration becomes difficult while adjusting the rotary speed when the load has reached the preset upper maximum load. In this case, the torque is transmitted to the pulley 7 connected to a motor 6 for rotation of the rod and the torque transmission pulley 11 through belts. And an automatic cramp 10 containing a load meter/torque meter in the inside is fixed in the center of the torque transmission pulley 11. And further, a vertical-vibration generator 12 is connected to the lower face of the torque transmission pulley 11 so as to vertically transmit vibration without transmission of the torque. And a container box 8 for vertically moving devices is moved up and don to penetrate the rod or pull out it. When judging the soil quality of the investigated ground, a hollow screw type resistant is used in order to take soil samples while measuring the penetration resistance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to ground exploration for obtaining ground information by penetrating a resistor into the ground. The penetration method is static penetration, rotation penetration, or vibration depending on the penetration resistance of the ground.・ By adding shock penetration in sequence,
The present invention relates to a simple portable device and method capable of highly accurate exploration from soft ground to hard ground.

[0002]

2. Description of the Related Art Among conventional in-situ ground survey methods, the method most widely used at present is the standard penetration test, which is the most widely used exploration method for obtaining ground information by penetrating a resistor into the ground.
It is ISA1219, and this exploration method records the number of hits when the sampler, which is a resistor, is hit with the specified energy per hit to penetrate the ground to the specified depth, and It is used together with sampling.

According to the JIS A1220 standard Dutch double tube cone penetration test method, the cone as a resistor is set to 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 load. .

As shown in FIG. 1, the Swedish type sounding test method of the JIS A1221 standard involves clamping via a rod (4) for connecting a resistor consisting of a screw point (5) to this and a clamp (3) for loading. A total of 100kg including 2 pieces of 10kg including a weight of 5kg and 3 pieces of 25kg, the depth of penetration with 6 kinds of weights (2) is recorded, and the maximum load is 100k.
When the subsidence is stopped at g, the handle (1) connected to the upper end of the rod is used for rotational penetration, and the rotational speed for the specified penetration amount is recorded. The screw point (5) is a quadrangular pyramid-shaped steel material twisted once over its entire length as shown in FIG.

As described above, the conventional typical ground exploration method is the standard penetration test method by the impact penetration method, and the Dutch double pipe cone penetration test for recording the load when the resistance body is penetrated while controlling the speed. The method consists of 6 kinds of penetration amount and Swedish sounding, which applies rotational force to maximum load.

[0006]

The problems of the prior art are as follows.
In the standard penetration test, in which the resistor sampler is penetrated and the ground information is obtained from the number of hits, the range of ground that can be measured is wide in principle, but the measurement accuracy is poor. Especially on soft ground, the number of hits is several times or less than once, which is extremely bad. This type of test method includes a simpler dynamic cone penetration test method, a large dynamic penetration test method for gravel ground that also serves as a sample collection like the standard penetration test, but the same problem as the standard penetration test method is there.

The penetration speed control type cone penetration test method is a method of obtaining ground information from the penetration load, and the Dutch double pipe cone penetration test method is a typical method. This method enables highly precise exploration from soft ground to medium-hard ground by controlling the penetration speed to a constant level. However, large penetration reaction force is required in medium-hard ground, and it is not possible to explore medium-hard ground in the case of topsoil layers where it is difficult to install screw anchors or in conditions where it is difficult to carry large weights. There's a problem. Although various methods such as an electric cone and a three-component cone have been developed for this type of test method, the cone has a similar problem because it is a non-rotating statically press-fitting method. It should be noted that although there is a drawback that it is difficult to determine the soil quality because it is not possible to collect a sample, the recent three-component cone can be determined to some extent from three types of measured values.

There is Swedish-type sounding as a method for measuring the amount of penetration by constant-load loading using a six-stage weight and for obtaining ground information from the number of revolutions by penetration with maximum loading and rotational force. While this exploration method has the advantage of not requiring a large reaction force device, it is extremely inaccurate because the load is 6 levels on soft ground. There is a basic defect that the penetration efficiency is very small in medium to hard ground due to poor rotation efficiency, and it spins idle when the screw point hits gravel etc. and does not penetrate with rotational force. In addition to this, because it is done manually, human error is introduced, the exploration efficiency is poor, and the exploration depth is shallow. Another problem is that the soil classification is ambiguous because it is not possible to collect samples at present.

[0009]

SUMMARY OF THE INVENTION The present invention aims to solve the problems of the prior art as shown in the following five items. 1. To enable highly accurate exploration even on soft ground. 2. To enhance the penetration ability in medium-hard ground and to have sufficient penetration ability as a support layer survey for pile foundations. 3. A method and device that do not require installation of screw anchors or transportation of large weight as penetration reaction force. 4. It is possible to collect the ground sample while exploring it as necessary so that the soil quality of the exploration ground can be identified. 5. The various acquisition methods and their combinations, and the exploration control and recording were automated to eliminate human error and to widen the measurement range and achieve high efficiency.

Means for solving the above matters will be described below. The present invention relates to an exploration method and device whose main purpose is to obtain ground strength information from resistance when a screw-shaped resistor penetrates into the ground, and forcibly applies rotational torque to the resistor in a soft formation. It is possible to obtain a highly accurate relationship between the penetration load and the penetration depth by adopting a method that allows the penetration at a constant speed without giving it to the It is a method to obtain the strength information of the ground from the number of rotations and the torque by making a constant speed penetration by adding a rotational force. It is characterized in that a special reaction force is not required by setting the set upper limit penetration load to a load within a sufficient range by the reaction force of the device itself or the reaction force obtained by combining the device weight and the weight of the measurer.

Further, according to the present invention, in the above-mentioned method, in the case of the hard formation which cannot penetrate even if the rotation speed reaches the set upper limit value,
The feature is that the penetration ability is enhanced by adding vibration and impact load.

A flow chart of the above exploration method is shown in FIG. First, the search is started at, and the penetration load P is adjusted so that the penetration speed V becomes the set value V ₀ as shown in. In this case, it is possible to prevent the screw point from naturally rotating due to the penetration without forcibly applying the rotational force, and the measured torque T = 0.
Then, the penetration is continued under the condition that the penetration load P is smaller than the set value P _0, and the condition is changed when the penetration load P reaches the set upper limit load P ₀ . Penetrates while adjusting the rotation speed R so that it becomes V ₀ and P ₀ . If the setting condition of is satisfied, the process is executed as it is, and the rotational force is not forcibly applied in order to penetrate at the set penetration speed (R <R ₀ , T = 0).
Is changed when the soft ground becomes such that the penetration load P becomes equal to or less than the set value P _0. Conversely, the penetration resistance is large and the set penetration speed V ₀ and the set penetration load P ₀ are set, and the set upper limit rotation speed R ₀ is set. If both or both of the installation upper limit torque T ₀ and the installation upper limit torque T ₀ are investigated even a little, the condition is changed to. In order to penetrate at the set penetration speed, penetration load P and rotation speed R
Set the conditions of T and T, and apply vibration / impact load. In the normal ground, P = P ₀ and T = 0, and when the penetration speed becomes slower, the rotation penetration is also used and the penetration is made at V ₀ .
Then, when the penetration speed V becomes smaller than V ₀ and the penetration becomes difficult, for example, when the penetration speed becomes half, the operation is stopped.

By using the above method, it becomes possible to obtain ground information in a soft formation with the same accuracy as in the static cone penetration test. Further, in the medium-hard strata, it is possible to carry out constant-speed intrusion by changing the rotation speed, so that it is possible to carry out exploration more reliably and with higher accuracy 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-type 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. A pulley (7) connected to a motor (6) for rotating a rod and a rotational force transmission pulley (11) having a hole (not shown) through a rod are shown. There is no belt to transmit the rotational force. A load meter / torque meter built-in automatic clamp (10) (not shown) for measuring the penetrating load and torque of the rod is tightly connected to the center of the rotational force transmission pulley (11). The vertical vibration transmitter (12) is connected to the lower surface of the rotational force transmission pulley (11) and has a structure in which vibration is transmitted in the vertical direction but rotational force is not transmitted.

Further, a pulley (17) connected to the vertical movement motor (16) and a pair of right and left rotational force transmitting pulleys (18) when viewed from the front.
The rotating force is transmitted by a belt (not shown). The two torque transfer pulleys (18) are rotated by the operation of the motor, and the pair of rotation screw support columns (14) tightly connected thereto are rotated. Further, since a pair of nuts (not shown) set on the screw columns are tightly connected to the vertical movement device storage box (8), this box moves vertically, and as a result, a rod (not shown) Will be intruded and pulled out. The reaction force due to the rod penetration is the weight of the device including the pedestal (19) and the scaffold (15) for the operator.
The body weight of the person who is not shown is set as the usable range. The screw receivers (9) and (21) fix the horizontal and axial movements of the rotary column (14) and support it in a freely rotatable state. The safety sensor (20) is a safety device that operates when the pedestal (19) cannot withstand the penetration and rotational reaction force and is displaced relative to the ground. The slide guide and column (13) is for transmitting the pushing reaction force and the torsion reaction force to the pedestal (19).

When it is necessary to determine the soil quality of the surveyed 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 portion is smaller than the inner diameter of the rod in order to prevent the collected sample from falling 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]

[Operation] As described above, the method of penetrating the resistor is sequentially increased from static penetration depending on the hardness of the ground, and rotational penetration and vibration / impact penetration are used in combination to improve the accuracy and the penetration ability dramatically. I was able to. Also, by automating the above-mentioned various penetration methods and their combined control, and measurement / recording, labor-saving, highly efficient and highly accurate exploration became possible.
Furthermore, the adoption of the hollow resistor has enabled us to collect a sample for soil classification at the same time as exploration.

[0019]

EXAMPLE An implementation 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 guideline for the usual static cone penetration test. The set upper limit of the penetration load P is the same as JIS A1211 standard P ₀ = 100k
Let g. Rotation speed R is set upper limit value R ₀ = 120r.pm
However, since the vibration of the device was large, I set it to 60r.pm again. The 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 and viscous land layer with a thickness of less than 10 m, and a medium to solid sand layer under the ground layer. The apparatus shown in FIG. 4 is used according to the flow chart of FIG. Carried out. In the topsoil layer, it stopped hitting the rubble and the rotation speed became high, reaching the set upper limit, but the torque was very small. This is because it hit gravel and cannot be penetrated by the normal loading rotary penetration method. Therefore, P = 100kg
When vibration loading was carried out in the loaded state, penetration began, so the method was switched to the regular exploration method and restarted. As a result, it penetrated at T = 0 up to a depth of 10.3 m, but the result was that the penetration resistance was considerably increased in the depth direction. However, each time a rod with a length of 1 m was added, a lifting load corresponding to the weight of the rod underwater was applied and the resistance was measured when the rod slowly rotated at 1 r.pm. The penetration resistance value increased only about 30kgf per 10m depth. The sand layer below this was in a rotational intrusion state, and the converted number of revolutions per 1 m of intrusion amount was 100 to 300 times.

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, about 140 kg, and the rotation torque increased in the sand layer, the pedestal (19) moved, and the safety sensor actuated to automatically stop.

[0023]

EFFECTS OF THE INVENTION In Swedish sounding that has been conventionally performed, the strength information of soft ground can be obtained only in six steps, but in the present invention, it is possible to measure with the same accuracy as in the static cone penetration test. did it. On medium to hard ground, unlike the conventional method, it is possible to reliably search at a penetration speed of 1 cm per second, so it has become possible to perform in a fraction of the time required by the conventional method. Especially in the ground with large penetration resistance, the penetration capacity is several times larger than that of the conventional rotary penetration method by human power, and the exploration efficiency is more than 10 times. Since the entire exploration system has been automated, two workers and one recording person have been used to lift and lower the 100 kg weight and press-fit.
What you used to do is now able to do all the work alone. In addition, it is now possible to make a distinction by observing the collected sample, which was used to empirically make a soil judgment based on the crushing sound at the time of penetration.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an outline of an entire apparatus of JIS A1221 standard, which is a conventional exploration method.

FIG. 2 is a side view showing a screw point which is a part of the apparatus shown in FIG.

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

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

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

[Explanation of symbols]

 1 Handle 2 Weight 3 Clamp for loading 4 Rod 5 Screw point 6 Rotor for rod rotation 7 Pulley 8 Vertical movement device storage box 9 Screw receiver 10 Automatic clamp with built-in load meter / torque meter 11 Rotational force transmission pulley 12 Vertical vibration generator 13 Thrust guide and strut 14 Rotating screw strut 15 Scaffold for measurer 16 Vertical movement motor 17 Pulley 18 Rotational force transmitting pulley 19 Pedestal 20 Safety sensor 21 Screw receiver 22 Rod 23 Hollow resistor sampler

Claims (7)

[Claims] 1. A rod having a ground penetration resistance element at its tip has means for separately or simultaneously transmitting a penetration load and a penetration rotational force, at a set penetration speed until the penetration load reaches a set upper limit penetration load. A resistance-penetration-type ground exploration device, characterized in that, when it penetrates and does not penetrate at a set penetration speed even when it reaches a set upper limit penetration load, it makes rotation penetration with the set upper limit penetration load being applied. 2. The rod of the apparatus according to claim 1 further comprises means for applying a vibration / impact load in the penetrating direction, even if a set upper limit penetration load and a set upper limit rotation speed or a set upper limit torque are applied to the rod. A resistance-penetration-type ground exploration device, which further applies vibration and impact loads to the rod when it does not penetrate at a set penetration speed. 3. The ground exploration device according to claim 1, wherein not only the penetration resistance can be measured but also a ground sample can be collected by using a hollow screw-shaped resistance body as the ground penetration resistance body. 4. The apparatus according to claim 1, wherein control and recording of penetration load, rotation speed, vibration / impact load, penetration amount, etc. are automated. 5. A rod for transmitting a penetrating load and a penetrating rotational force is connected to an upper end portion of the ground penetrating resistor, and the penetrating load is penetrated at a set penetrating speed until the penetrating load reaches a set upper limit penetrating load. Obtaining strength information, if it does not penetrate at the set penetration speed even if it reaches the set upper limit penetration load, it is rotationally penetrated in the state where the set upper limit penetration load is applied, from the rotation torque, or from the number of revolutions per unit amount of penetration, Alternatively, a ground exploration method characterized by obtaining information such as the ground strength constant from both of them. 6. The method according to claim 5, wherein when the set upper limit rotation speed is reached and the set upper limit rotation speed is not reached when the set penetration speed is reached, the set upper limit penetration load is applied. When the torque does not penetrate at the set penetration speed even if the torque is reached, or in any of these cases, or when both conditions are satisfied, apply the set vibration / impact load in addition to the set upper limit penetration load and the set upper limit rotational force. Ground exploration characterized by obtaining information such as the strength constant of the ground from the number of revolutions at the set penetration speed and obtaining the information such as the strength constant of the ground from the penetration speed after reaching the set upper limit penetration speed or torque. Method. 7. The measured resistance value obtained by the method according to claim 5 or 6 is corrected by rotating the rod without applying a load to the penetration resistor to obtain the relationship between the rotation speed and the rotation resistance. Technique to do.