WO2019111883A1

WO2019111883A1 - Ground surveying method and bladed cone

Info

Publication number: WO2019111883A1
Application number: PCT/JP2018/044533
Authority: WO
Inventors: 英一郎佐伯; 孝次時松; 秋男阿部
Original assignee: 株式会社東京ソイルリサーチ; 英一郎佐伯
Priority date: 2017-12-06
Filing date: 2018-12-04
Publication date: 2019-06-13
Also published as: JPWO2019111883A1; CN111263839B; CN111263839A; JP6532637B1

Abstract

Provided are a low-cost ground surveying method and a bladed cone, with which it is possible to continuously determine the penetration resistance of ground quickly and with high precision using a light and small construction machine, in order to be capable of penetrating hard and deep ground even with a low load vertical force using a high blade propulsion force due to the blade reaction force generated in the earth by a low load torque. The present invention comprises: a bladed cone 1 having a cone part 2 that has a diameter that decreases in the penetration direction, and a spiral blade part 3 provided on the outer peripheral surface 2a of the cone part 2, the width of the spiral blade part 3 decreasing toward a tip end 4; and a rod 7 attached to a lower end 5 of the bladed cone 1; the bladed cone 1 being caused to penetrate ground 9 to be surveyed using load torque and load vertical force applied to an upper part 6 of the rod 7, and the penetration resistance of the ground 9 to be surveyed being evaluated on the basis of action torque and action vertical force acting on the bladed cone 1, or on the basis of the action torque and the action vertical force acting on the bladed cone 1 and the penetration amount per rotation of the bladed cone 1.

Description

Ground survey method and bladed cone

The present invention belongs to the technical field of a ground survey method using torque required for rotational penetration and a bladed cone suitable for implementation of the ground survey method.

Conventionally, as ground investigation methods, there are (A) standard penetration test, (B) cone penetration test, and (C) Swedish-type sounding which are schematically shown in FIG. In addition to that, (D) rotary sounding is well known, and (E) there is one that carries out support layer confirmation using torque of a rotary penetration pile.
(F) Patent Document 1 relating to Patent No. 379 8281: “When rotating a rod having a cutting blade at its tip into a ground, the rotational load and the depth of the tip of the rod are continuously measured. In the ground investigation method, the rotational load at the time of press-in with the rod head is measured, and the rotational load at the time of reverse rotation and withdrawal is measured to separate the rotational load acting on the rod shaft, A ground investigation method characterized by calculating only a rotational load acting on the tip portion is disclosed (see claim 1 of the patent document 1).

Patent No. 379 8281

The standard penetration test (A) is time-consuming and costly because it requires replacing the tip device to perform the standard penetration test, in addition to the cost and time for boring. Although this is a dynamic penetration test, a large construction machine is not required, but the N value can be obtained only for every 1 m as the number of falling of the hammer, not a continuous value. There is also a problem that the dynamic penetration resistance has large variations.
The cone penetration test of (B) requires a dynamic clear value because it is a penetration test using only static vertical load, but a large pushing force is required and it is impossible to investigate a deep and hard ground. Deep ground investigation is also difficult because of the large friction on the surface of the rod.
The Swedish sounding (C) uses vertical force and load torque on the cone and is suitable for soft ground investigations, but it does not have a large impetus and can not investigate deep hard ground. In addition, penetration resistance can be obtained only every 0.25 m as the number of rotations, etc., and it is not a continuous value.
The rotary sounding of (D) uses a load vertical force and a load torque, but is a “cutting in” by applying the load vertical force and has no propulsive force. Moreover, since the shape of the tip is not simple, there is no means for evaluating the cone penetration resistance, the N value, etc. from the load vertical force and torque. Moreover, the cost is high and not widespread.
Those that perform support layer confirmation using the torque of the rotating penetration pile of (E) are expensive when used for ground surveys. Moreover, since the shape of the tip is not simple, there is no means for evaluating the cone penetration resistance, the N value, etc. from the load vertical force and the load torque.
In the ground investigation method according to Patent Document 1 of (F), the difference between the penetration torque and the pulling-up torque by reverse rotation is a point. Because the penetration resistance of the tip portion is large, a large loading torque is required, and the construction machine becomes large. Therefore, there is a problem that the cost is high and the place where it can be used is limited.

The object of the present invention is that by using a bladed cone, it is possible to penetrate into a solid and deep ground even with a small load vertical force by a large blade driving force due to a blade reaction force generated in the ground (ground to be surveyed) by a small load torque. An object of the present invention is to provide a low-cost ground survey method and a bladed cone capable of continuously determining the penetration resistance of the ground with high accuracy and speed by a lightweight and small construction machine.
Further, the next object of the present invention is that the action torque and the action vertical force acting on the bladed cone based on the action torque and the action vertical force acting on the bladed cone or per rotation of the bladed cone It is an object of the present invention to provide a ground investigation method and a bladed cone which make it possible to easily evaluate the cone penetration resistance and the N value based on the penetration amount of

As means for solving the above problems, the ground survey method according to the invention described in claim 1 is provided with a cone portion 2 which is reduced in diameter in the penetration direction, and an outer peripheral surface 2 a of the cone portion 2 and a tip 4 And a rod 7 for attaching the bladed cone 1 to the lower end 5, and the load torque and load vertical force applied to the upper portion 6 of the rod 7 The bladed cone 1 is made to penetrate into the ground 9 to be surveyed, and the acting torque and the acting vertical force acting on the bladed cone 1 based on the acting torque and the acting vertical force acting on the bladed cone 1 The penetration resistance of the ground 9 to be surveyed is evaluated based on the penetration amount per one rotation of the bladed cone 1.

[Correction based on rule 91 28.12. 2018]
The invention described in claim 2 is the ground survey method according to claim 1,
When evaluating the penetration resistance of the survey target ground 9 based on the acting torque acting on the bladed cone 1 and the acting vertical force:
It is characterized in that the cone penetration resistance and the standard penetration test N value (hereinafter abbreviated as N value) are evaluated by the following formula.
Cone penetration resistance (q _c ) = (T _b C ₂ / r _w ′ + L _b C ₁ ) / (C ₁ + C ₂ μη / C ₃ ) / (α A _e )
N value _{_{= (T b C 2 / r}} w '+ L b C 1) / (C 1 + C 2 μη / C 3) / (αβA e)
C ₁ = sin θ + μ cos θ, C ₂ = cos θ−μ sin θ, C ₃ = sin ω + μ cos ω
Action torque acting on T _b bladed cone
L _b Vertical force acting on the bladed cone r _w 'Equivalent operating radius of blade frictional resistance torque η Equivalent operating radius of penetrating frictional resistance torque (r _e ') and equivalent operating radius of blade frictional resistance torque (r _w ') Ratio of friction coefficient of friction between ground and blade ω angle from center axis of cone tip θ equivalent inclination angle of blade
A _e Determined from the relationship between the equivalent penetration cross section α q _{c of the} cone with a blade and R _p (vertical penetration resistance) Coefficient determined from the relationship between β q _c and N value

The invention described in claim 3 is the ground survey method according to claim 1,
In the case of evaluating the penetration resistance of the ground 9 under investigation based on the acting torque acting on the winged cone 1, the acting vertical force, and the penetration amount per one rotation of the winged cone 1:
When the vertical penetration amount (s) per one rotation of the bladed cone is equal to or smaller than the blade pitch (P),
The cone penetration resistance and the N value are evaluated by the following equation from the acting torque, the acting vertical force, and the penetration amount per one rotation of the bladed cone.
Cone penetration resistance (q _c ) = (2πT _b + L _b s + 2πμw _w 'L _b / (C ₂ cos θ)) / (s + 2π μr _e ' / C ₃ + 2π μr _w '/ (C ₂ cos θ)) / (ΑA _e )
N value _{_{= (2πT b + L b s}} + 2πμr w 'L b / C 2 cosθ) / (s + 2πμr e' / C 3 + 2πμr w '/ (C 2 cosθ)) / (αβA e)
C ₂ = cosθ-μsinθ, C ₃ = sinω + μcosω
Action torque acting on T _b bladed cone
L _b Vertical force acting on a bladed cone s Vertical penetration amount r _w 'per one rotation Equivalent radius of blade friction torque r _e ' Penetration frictional resistance torque equivalent radius of action μ Ground and blade friction coefficient ω cone Angle θ from the center axis of the tip Equivalent inclination angle of the blade
A _e Determined from the relationship between the equivalent penetration cross section α q _{c of the} cone with a blade and R _p (vertical penetration resistance) Coefficient determined from the relationship between β q _c and N value

According to the invention described in claim 4, in the ground survey method described in claim 1,
In the case of evaluating the penetration resistance of the ground 9 under investigation based on the acting torque acting on the winged cone 1, the acting vertical force, and the penetration amount per one rotation of the winged cone 1:
When the vertical penetration amount (s) per one rotation of the bladed cone is larger than the blade pitch (P),
The cone penetration resistance and the N value are evaluated by the following equation from the acting torque, the acting vertical force, and the penetration amount per one rotation of the bladed cone.
Cone penetration resistance (q _c ) = (2πT _b + L _b s) / (s + 2πμ r _e '/ C ₃ ) / (α A _e )
N value = (2πT _b + L _b s) / (s + 2πμr _e '/ C ₃ ) / (αβA _e )
C ₃ = sin ω + μ cos ω
Action torque acting on T _b bladed cone
L _b Vertical force acting on the bladed cone s Vertical penetration amount per rotation r _e 'Equivalent friction radius of penetration friction torque Torque coefficient of friction between ground and blade ω Angle from central axis of cone tip
A _e Coefficient determined from the relationship between the equivalent penetration cross section α q _{c of the} cone with a blade and R _p (vertical penetration resistance) Coefficient determined from the relationship between β q _c and the N value

The bladed cone 1 according to the invention described in claim 5 is the above-mentioned bladed cone used in the ground survey method according to any one of claims 1 to 4, and a cone portion which reduces in diameter toward the tip 4 2 and a spiral blade 3 provided on the outer peripheral surface 2a of the cone 2 and having a narrower width toward the tip 4.

The invention described in claim 6 is characterized in that, in the bladed cone 1 described in claim 5, the blade pitch of the bladed cone is 0.5 to 1.5 times the outermost diameter of the cone. .

Since the ground investigation method according to the present invention uses a bladed cone provided with a spiral blade whose width is narrowed toward the tip to the tip cone whose outer diameter decreases toward the tip, penetration resistance of the tip portion is small. Therefore, the bladed cone can be penetrated into the ground with a small load torque and load vertical force. In addition, since this shape has good penetration and penetrates more than the blade pitch per rotation, the balance between the force acting on the bladed cone and the resistance becomes clear, and the ground resistance (strength) with high accuracy can be calculated by the evaluation formula described later. It is possible to predict. In addition, since there is a large blade driving force at the tip, penetration into a deep and hard ground can be made vertically without tilting. Therefore, not only a large pressing force is required, but also penetration can be achieved with high straightness and high accuracy of the tip position.
Since the strength of the ground on the circumferential surface of the rod is reduced by the rotation, the circumferential friction force acting on the rod becomes very small, and the loading torque and the loading vertical force can be efficiently transmitted to the lower end of the rod. Therefore, the difference between the "load torque and load vertical force" at the top of the rod and the "action torque and vertical force acting on the bladed cone at the lower end of the rod" is small, making it possible to evaluate the penetration resistance of the tip ground with high accuracy. As a result, the ground survey method according to

claim

2, 3 or 4 can accurately convert the acting torque and the acting vertical force into the cone penetration resistance value and the N value used in practice.
In addition, this investigation method can obtain continuous data on penetration resistance, not discrete data of 1 m per N value.
The bladed cone according to claim 6 has an optimum shape that achieves the minimum torque when the blade pitch is 0.5 to 1.5 times (especially 0.5 to 1.0 times) the outermost diameter of the cone. Ru. As a result, since it can investigate with construction machinery with small size and ability, cost reduction can be aimed at, and ground investigation in narrow roads and sites becomes possible.
In addition, the ability to conduct surveys without drilling and the possibility of more rapid surveys by increasing the number of revolutions enables a significant reduction in the construction period.

It is explanatory drawing which showed the typical construction method of the ground investigation method of this invention. It is explanatory drawing of the force and torque which arise in the ground investigation of this invention. It is explanatory drawing of the front-end | tip shape of the bladed cone used for the ground investigation method of this invention, the stress degree which acts on it, and an equivalent action circle. It is explanatory drawing which showed the relationship between the equivalent cone and the equivalent cylinder, and the relationship between the stress degree which acts on an equivalent cone, and a vertical penetration resistance force. It is the schematic diagram which showed balance of the force on "the equivalent action circle of blade friction resistance torque" in a bladed cone. It is a comparison table with the conventional ground investigation method and this invention. The right figure is a graph of q _c -depth relationship determined from the ground survey, and the left figure is a graph of q _c -depth relationship determined by a conventional cone penetration test. The right figure is a graph of the N value-depth relationship determined from the ground survey, and the left figure is a graph of the N value-depth relationship determined by the conventional standard penetration test. It is the graph which showed the relationship between the action torque of a bladed cone, and a blade pitch rate.

Hereinafter, preferred embodiments of the ground survey method of the present invention and the bladed cone used in the ground survey method will be described according to the drawings.

The bladed cone according to this embodiment shown in FIG. 4 is a ground survey carried out by inserting the bladed cone 1 into the ground 9 by applying a load torque and a load vertical force to the upper portion 6 of the rod 7 (see FIG. 1). Used in the method. Vaned cone in this embodiment the maximum cone diameter D _o is 40 mm, the maximum blade diameter D _w is 60 mm, total length at 208 mm, and the cone portion 2 whose diameter decreases toward the penetration direction of the distal end 4, the cone portion 2 The outer peripheral surface 2 a is configured to include a spiral blade portion 3 formed in a blade shape in which the width narrows toward the tip 4 and spirals. The optimal shape of the spiral blade 3 will be described later. In addition, it should be noted that each of the dimensions is just an example.

The bladed cone 1 is attached to the lower end 5 of the rod 7 as illustrated in FIG. 1, and the upper end 6 of the rod 7 operates (the driving device of) the construction machine 8 to load torque and load vertical force. It is rotationally penetrated to the ground 9 by adding. The penetration resistance of the ground 9 can be evaluated based on the value of the load torque and the load vertical force at that time.

In the examination method, when the “loading torque” and the “loading vertical force” are applied to the upper portion of the rod 7, the “action torque” and the “action vertical force” act on the bladed cone 1. When the influence of the circumferential friction of the rod 7 (“rod circumferential friction torque” and “rod circumferential frictional resistance”) can be ignored, the loading torque and the applied vertical force are the acting torque and the acting vertical force.
On the other hand, when the influence of the surface friction of the rod 7 can not be ignored, the action torque and the action vertical force are obtained by subtracting the influence of the surface friction of the rod 7 from the load torque and the load vertical force. The force and torque generated in the bladed cone 1 by the action torque and the action vertical force are the four values of “vertical penetration resistance force”, “penetration friction resistance torque”, “vane propulsion force”, and “vane friction resistance torque”. is there.

The loading method includes a displacement control method in which the penetration amount s is controlled to be equal to the blade pitch P and a load control method in which the loading vertical force is controlled to be constant. In the case of the load control method, there are the following two cases of penetration amount per one rotation.
(1) In the case of s ≦ P (when there is a blade propelling force)
When the vertical penetration resistance is larger than the acting vertical force in a hard ground or the like, blade propelling force is generated, and in general, the amount of penetration per one rotation is equal to the blade pitch. When the ground strength rapidly increases (hardens rapidly), the amount of penetration per one rotation may be smaller than the blade pitch.
(2) In the case of s> P (when the blade propelling force is zero)
When the vertical penetration resistance is smaller than the acting vertical force in a soft ground or the like, the blade propelling force becomes zero, and the amount of penetration per one rotation becomes larger than the blade pitch.

Hereinafter, “vertical penetration resistance force”, “piercing frictional resistance torque”, “vane propulsion force”, “vane frictional resistance torque” acting on the bladed cone at the time of rotational penetration, and the balance of the forces will be described in detail.
(1. Vertical penetration resistance)
Vertical penetration resistance R _p of the bladed cone shown in FIG. 3 is an index having the same characteristics as the cone penetration resistance q _c, it is considered an indicator of the high correlation rigidity and strength and earth removal volume of soil. Therefore, attention is paid to “the total volume V _w of the blade and the shaft portion of the largest diameter portion of the bladed cone for discharging per one rotation when the bladed cone is penetrating at a penetration amount s per rotation. V _w can be expressed by the following two equations depending on the difference in penetration amount.
When s ≦ P V _w = t (r _w -r _o ) ls / P + A _o s
When s> P V _w = t (r _w -r _o ) l + A _o s + A _w (sP)
t: blade thickness, r _w : maximum radius of the blade,
r _o : maximum inner diameter of blade and maximum radius of cone shaft, A _o : maximum cross-sectional area of cone,
l: A spiral length of the center of the blade per rotation of the blade cone shaft (== (P ² + (2π (r _w + r _o ) / 2) ² ) V _w A cylinder of the same volume and height P as _w If we define an equivalent cylinder and let its cross section be the equivalent penetration cross section A _e and its radius be r _e
A _e = V _w / s, r _e = √ (A _e / π)
It is.
A cone similar to the tip cone and having a base radius r _e is considered as an “equivalent cone”, and the balance of forces of the “equivalent cone” is considered. Normal stress acting on the conical peripheral surface in extreme equilibrium in the ground (the surface pressure) was assumed to be uniformly distributed, the normal stress level per unit area and p _p. Those vertical penetration resistance force R _p is multiplied by the equivalent conical circumferential area _{^{A c (= πre 2 / sinω}} ) to the sum of the axial component of the frictional stresses .mu.p _p acting in the axial direction component and the conical circumferential surface of the p _p Because there is
R _p = p _p (sin ω + μ cos ω) A _c
= p _p C ₃ A _c (1-1)
C ₃ = sin ω + μ cos ω
μ: coefficient of friction, ω: angle from the central axis of the cone tip.

(2. Penetration friction resistance torque)
As shown in FIG. 3, the rotation caused by the vertical penetration generates a frictional stress degree μp _p in the circumferential direction of the equivalent cone. Since the surface area of the small width dr of the cone peripheral surface at the position r from the central axis of the equivalent cone is 2πr · dr / sinω, the friction force acting on the surface area is 2πr · dr / sinω · μp _p Directional frictional force (total force of frictional force) Fμp is a value obtained by integrating this from 0 to re: F _μp = ∫2πμp _p / sin ω rdr = πμp _p r _e ² / sin ω = π r _e ² / sin ωμp _p = μ _{p p} A _c
It becomes.
T _p penetration friction torque T _p in the circumferential direction in the integrated value of the ^{2πr 2 · dr / sinω · μp} p multiplied by the radius r of the cone each located 2πr · dr / sinω · μp _p from 0 to r _e = ∫ 2πμp _p / sin ωr ² dr = 2 / 3π μp _p r _e ³ / sin ω = 2/3 r _e μp _p A _c
= 2/3 r _e F _{μ p} = r _e 'F _{μ p}
It becomes.
The circle on which the resultant force F _μp of the frictional force acts to convert it into torque is called the equivalent action circle, and the radius thereof is called the equivalent action radius. The above “r _e ′” is an equivalent action radius, and is also a value (∫2πr ² dr / (πr _e ² ) = 2/3 r _e ) obtained by dividing the first polar moment of area by the area.
Since p _p = R _p / (C ₃ A _c ) from the equation (2-1), F _μp = μR _p / C ₃ (2-1)
It can be expressed as.
Therefore, the circumferential penetration friction resistance torque T _p associated with the vertical penetration resistance is
T _p = F _μp r _e '= μR _p r _e r / C ₃ (2-2)
It can be expressed as.

(3. Blade propulsion)
The force acting on the blade by the wedge effect when the bladed cone rotates and penetrates, as shown in FIG. 4, is a direction of rotation generated by the blade driving stress degree p _a acting perpendicularly to the upper surface of the blade and the driving stress degree. consists of vanes friction stresses .mu.p _a, assumed to be respectively like distribution.
Blade thrust P _w can be approximated by _{_{P w = p a (1 /}} cosθ) pA w. (PA _w : Sum of projected area of the blade with a bladed blade)
In order to calculate the component of the vertical direction (vane propulsion) due to the propulsion pressure or the rotational component of the frictional force, the vertical inclination angle along the circumference of the vane and the equivalent action radius of the frictional force are required. Become. The angle of inclination of the blade and its equivalent working circle when there are n blades of the blade differ depending on the position. Therefore, when considering the balance of force of the winged cone, the equivalent inclination angle and the equivalent action radius shown below are used.

(4. Blade frictional resistance torque and its equivalent action radius and equivalent inclination angle)
The equivalent action radius and the equivalent inclination angle of the circumferentially acting force such as the frictional force by the blade driving force can be determined as follows.
When blade outer and inner diameters of the blade rotation angle is [psi helical blade when there n Zhou, the maximum outer radius to the maximum radius of r _w blade cone shaft and r _o, the polar coordinates (r-ψ) It can be expressed as follows.
Outer radius: r = r _w ψ / (2 n π)
Inner radius: r = r _o ψ / (2 n π)
The small projected area dA _pw of the "fan-shaped" blade of the small rotation angle d 角 at the position of the rotation angle d is dA _pw = (1/2) (r _w ψ / (2nπ)) ² d ψ-(1/2) ( r _o ψ / ( ² n π)) ² dψ
= (1/2) ((r _w ψ / 2nπ) ^2- (r _o ψ / 2nπ) ² ) d ψ = (r _w ² -r _o ² ) / (8π ² n ² ) ψ ² d ψ
It is. Assuming that the inclination angle on the equivalent action circle is δ (a value inversely proportional to ψ), the minute blade area dA _w is dA _w = d pA _w / cos δ = (r _w ² -r _o ² ) / (8π ² n ² ) / cos δdψ
Therefore, the circumferential component force dF _w of the blade friction stress acting on the minute blade area dA _w is dF _w = μ p _a d A _w cos δ = μ p _a (r _w ² -r _o ² ) / (8π ² n ² ) / cos δ cos δ ψ ² d ψ
= μ p _a (r _w ² -r _o ² ) / (8π ² n ² ) ψ ² dψ
It is.
The circumferential summation F _w of the blade friction stress degree generated by the blade driving force is obtained by integrating the above equation by 0 → 2 nπ F _w = ∫μ p _a (r _w ² − r _o ² ) / (8 π ² n ² ^{_{) ψ 2 dψ = μp a (}} r w 2 - r o 2) / (8π 2 n 2) (8n 3 π 3/3)
= μ p _a n π (r _w ² -r _o ² ) / 3
It becomes.
The equivalent action radius r _wd 'of the ring of outer diameter rwψ / (2nπ) and inner diameter roψ / (2nπ) is r _wd ' = 2 ((ψr _w / (2nπ)) ^3- (ψ r _o / (2 nπ)) ³ ) / (3 ((ψ r _w / ( ² n π)) ^2- (ψ r _o / (2 n π) ² ))
Since it is ((Supplement)), the vane frictional resistance torque dT _w acting on the small wing area dA _w is
_{_{_{dT w = dF w r wd '}}} = μp a (r w 2 - r o 2) / (8π 2 n 2) ψ 2 dψ (2 ((ψr w / (2nπ)) 3 - (ψr o / (2n π )) ³ ) / (3 ((ψ r _w / ( ² n π)) ^2- (ψ r _o / (2 n π) ² )))
= μ p _a (r _w ² -r _o ² ) / (8 π ² n ² ) 2 (r _w ^3- r _o ³ ) / ( ² n π) / (3 (r _w ^2- r _o ² )) ψ ³ d ψ
= μ p _a (r _w ^3- r _o ³ ) / (24π ³ n ³ ) ψ ³ dψ
It is. The blade friction resistance torque T _w which is the sum thereof is obtained by integrating the above equation by 0 → 2 nπ,
_{_{_{T w = ∫μp a (r w}}} 3 -r o 3) / (24π 3 n 3) ψ 3 dψ = μp a (r w 3 -r o 3) / (24π 3 n 3) (2nπ) 4/4
_{_{^{= μp a (r w 3 -r}}} o 3) / (24π 3 n 3) (2nπ) 4/4
= μ p _a n π (r _w ^3- r _o ³ ) / 6
It is.
Since the equivalent action radius r _w 'of blade friction resistance torque is T _w / F _w ,
r _w '= T _w / F _w = (μ p _a n π (r _w ^3- r _o ³ ) / 6) / (p p _a n π (r _w ² -r _o ² ) / 3)
= (r _w ^3- r _o ³ ) / (2 (r _w ² -r _o ² )) (4-1)
It is.
In the case of this shape, r _w 'is a constant value regardless of n, and the equivalent action radius r _w1 ' = 2 (r _w ^3- r _o ) of the donut-shaped ring shown in the following (Supplementary) ³ ) / (3 (r _w ^2- r _o ² )) 3/4 of the value.
From this, the equivalent inclination angle θ is θ = P / (2πr _w ') = P (r _w ² −r _o ² ) / (π (r _w ³ −r _o ³ )) (4-2)
It becomes.

<Supplement> When the blade has a donut-shaped ring of one turn, when the equally distributed friction stress τ acts on the doughnut-shaped ring with an outer diameter r _w and an inner diameter r _o in the circumferential direction, the total sum The equivalent action radius r _w1 'of the blade friction resistance torque is r _w1 ' = 2 (r _w ³ -r _o ³ ) / (3 (r _w ² -r _o ² )) (Supplementary -1)
It is.

(5. Balance of power)
The balance of torque and force acting on the bladed cone when the blade pitch is penetrated, the balance of force on the equivalent operating circle of the spiral blade model having the equivalent operating radius r _w 'and the equivalent inclination angle θ Convert to
As shown in FIG. 4, the circumferential direction of “the equivalent action circle of the blade friction resistance torque” is taken as the weir axis. FIG. 5 is a diagram showing the balance of forces in the vertical (Z-axis) direction and the horizontal (Ψ axis) direction when the rod axis is in the horizontal (x) direction and the rod friction is ignored. The explanation of the symbols is given below.
H _t is a value T _b / r _w 'obtained by replacing the acting torque T _b acting on the bladed cone with a horizontal force on the "equivalent acting circle".
L _b is the acting vertical force acting on the bladed cone.
· Wings propulsion P _w is a resultant force of the wings promote stress the degree of p _a, it can be approximated by _{_{P w = p a (1 /}} cosθ) pA w.
(PA _w : Sum of projected area of the blade with a bladed blade)
F _w is a sum of circumferential component forces of the blade friction stress degree generated by the blade driving force with the blade friction resistance μP _w acting on “the equivalent action circle of blade friction resistance torque”.
R _p is the vertical penetration resistance.
Η is the ratio of the equivalent action radius (r _e ′) of penetration friction resistance torque to the equivalent action radius (r _w ′) of blade friction resistance torque.
· F _p is F a value obtained by converting the circumferential penetration frictional resistance force F _.mu.p the frictional force of the equivalent action radius r _w 'of the vane frictional resistance force F _w generated by the vertical penetration resistance _p = _ηF _μp = _μηR a _p / C _3.
The balance of force is shown below. Balance in the horizontal (Ψ axis) direction H _t = T _b / r _w '= μη R _p / C ₃ + P _w sin θ + μP _w cos θ (5-1)
・ Balance in the vertical (Z-axis) direction R _p = P _w cos θ + L _b- μ P _w sin θ (5-2)
Focusing on P _w we get
P _w = (H _t −μη R _p / C ₃ ) / (sin θ + μ cos θ) (5-3)
P _w = (R _p -L _b ) / (cos θ-μ sin θ) (5-4)
If P _w is eliminated and C ₁ = sin θ + μ cos θ and C ₂ = cos θ−μ sin θ, the following relational expression is obtained.
R _p = (T _b C ₂ / r _w '+ L _b C ₁ ) / (C ₁ + C ₂ μη / C ₃ ) (5-5)
The vertical penetration resistance force (R _p ) of the bladed cone can be expressed by a loading torque (T _b ) and a loading vertical force (L _b ).

The vertical penetration resistance R _p of the winged cone can also be expressed from the balance of energy and is shown below.
The bladed cone can be penetrated by applying torque and vertical force. Then equal energy E _c which is consumed by the input energy E _i and penetration per revolution, and E _i = E _c.

(6. Input energy E _i per rotation)
E _i can be expressed by the following expression.
E _i = L _b s + 2πT _b (6-1)
(7. Energy E _c consumed by penetration per revolution)
E _c can be expressed by the following formula.
E _c = E _s + E _μ
E _s : energy consumed per revolution by vertical penetration
E _μ : energy consumed per rotation friction The energy E _μ consumed by rotation friction can be expressed by the following equation.
E _μ = E _μp + E _μa
E _μp : Energy consumed per rotation due to penetration friction with rotation E _μa : Energy consumed per rotation due to blade friction with rotation
(7-1. Energy E _s consumed by vertical penetration)
E _s can be expressed by the following equation.
E _s = R _p s (7-1)
(7-2. Energy E _μp consumed per rotation due to penetration friction with rotation)
E _μp can be expressed by the following equation.
E _μp = 2πT _p
From equation (3-2), T _p = F _μp r _e '= μR _p r _e ' / C ₃ so that E _μp = 2π r _e 'μR _p / C ₃ (7-2)
(2-3. Energy E _μa consumed per rotation due to blade friction accompanying rotation)
E _μa considers the following two cases
The energy E _μa consumed per rotation due to blade friction accompanying rotation when s ≦ P is because the displacement amount of the friction surface per rotation is 2πr _w ′ (1 / cos θ)
E _μa = F _w · 2πr _w '(1 / cos θ) = 2πr _w ' μP _w (1 / cos θ)
From equation (9), P _w = (R _p -L _b ) / C _2, so E _μa = 2πr _w 'μ (R _p -L _b ) / C ₂ (1 / cos θ)
= 2πr _w 'μ (R _p- L _b ) / C ₂ / cos θ (7-3)
When s> P
Since P _w = 0, E _μa = 0.

(8. Balance of energy)
(When 8. の P)
From energy balance E _i = E _c
L _b s + 2πT _b
_{_{= R p s + 2πr e '}} μR p / C 3 + 2πr w' μ (R p -L b) / C 2 / cosθ
= R _p (s + 2 π r _e 'μ / C ₃ + 2 π _{r w} ' μ / (C ₂ cos θ))- ₂ π _{r w} 'μ L _b / C ₂ cos θ
From above
R _p = (2πT _b + L _b s + 2πμw _w 'L _b / C ₂ cos θ) / (s + 2π μr _e ' / C ₃ + 2π μr _w '/ (C ₂ cos θ)) (8-1)
C ₂ = cosθ-μsinθ, C ₃ = sinω + μcosω
Get

(When 8-2. S> P)
From energy balance E _i = E _c
L _b s + 2πT _b = R _p s + 2πμR _p / C ₃ r _e '
= R _p (s + 2πμ / C ₃ r _e ')
From above
R _p = (2πT _b + L _b s) / (s + 2πμ r _e '/ C ₃ ) (8-2)
C ₃ = sin ω + μ cos ω
Get

(9. N value and q _c and R _p )
Since R _p is the vertical penetration resistance of the ground, it has almost the same property as the cone penetration resistance q _c and is considered to have the following relationship.
R _p = αq _c A _e (9-1)
α: coefficient determined from the relationship between q _c and R _p , q _c : cone penetration resistance A _e : equivalent penetration cross section of bladed cone
There is the following relationship between N value and cone penetration resistance.
q _c / N = β
N: N value, β: By the relationship between q _c and N value,
R _p = αβ N A _e (9-2)
N value and R _p can also be related.

[Correction based on rule 91 28.12. 2018]
Therefore, the evaluation equation by “balance of forces” described in claim 2 can be obtained from the equations (9-1), (9-2) and (5-5)
Cone penetration resistance (q _c ) = (T _b C ₂ / r _w ′ + L _b C ₁ ) / (C ₁ + C ₂ μη / C ₃ ) / (α A _e )
N value _{_{= (T b C 2 / r}} w '+ L b C 1) / (C 1 + C 2 μη / C 3) / (αβA e)
C ₁ = sin θ + μ cos θ, C ₂ = cos θ−μ sin θ, C ₃ = sin ω + μ cos ω
It becomes.

The vertical penetration amount (s) per one rotation is the blade pitch (P) according to the equations (9-1), (9-2) and (8-1) based on the "balance of energy" described in claim 3. In the case of (the invention according to claim 3)
Cone penetration resistance (q _c ) = (2πT _b + L _b s + 2πμw _w 'L _b / (C ₂ cos θ)) / (s + 2π μre ′ / C ₃ + 2πμ r _w ′ / (C ₂ cos θ)) / (ΑA _e )
N value _{_{= (2πT b + L b s}} + 2πμr w 'L b / C 2 cosθ) / (s + 2πμr e' / C 3 + 2πμr w '/ (C 2 cosθ)) / (αβA e)
C ₂ = cosθ-μsinθ, C ₃ = sinω + μcosω
According to (Equation 9), (9-2) and (8-2), the vertical penetration amount (s) per rotation is the blade pitch (P). When larger than (the invention according to claim 4)
Cone penetration resistance (q _c ) = (2πT _b + L _b s) / (s + 2πμ r _e '/ C ₃ ) / (α A _e )
N value = (2πT _b + L _b s) / (s + 2πμr _e '/ C ₃ ) / (αβA _e )
C ₃ = sin ω + μ cos ω
It becomes.

(Example of survey results)
One example of the survey result implemented by this survey method is shown in FIG. 7 and FIG.
Figure 7 shows the results of the cone penetration test (left figure) conducted at two locations near the survey position and the q _c -depth relationship (from the energy balance equation for μ = 0.5, α = 1) Right).
According to FIG. 7, it can be seen that there is a good correlation with α = 1. This is can be seen that the vertical penetration resistance R _p of the cone penetration resistance and bladed cone is approximately the same value. The cone penetration test was interrupted at two points at a depth of about 17m and interrupted, but this survey method could investigate up to a depth of about 25m without problems.

Similarly, FIG. 8 shows the standard penetration test results in the vicinity (left figure) and the N value-depth relationship (right figure) obtained from the evaluation equation by “force balance” in the case of μ = 0.5, α = 1, β = 600 kP _a Indicates This also has a good correlation. β = 600 kP _a is consistent with previous research results on the correlation between N value and q _c . The "N value" according to the present invention can be obtained as continuous data as shown.

(Optimum blade pitch rate)
FIG. 9 shows the relationship between the blade pitch ratio (P / D _o ) and the acting torque in the case of t = 3, 4 and 6 mm for three cases of D _o = 48 mm and D _w = 60, 72 and 96 mm, respectively. It is what I asked for. When the blade pitch ratio is 0.5 to 1.5, the acting torque is small. Therefore, when the blade pitch of the bladed cone is 0.5 to 1.5 of the maximum diameter of the cone, it is efficient with a small acting torque. It turns out that it can penetrate.

<Description of symbols in the above equation>
Cross-sectional area of maximum diameter of A _o cone (area of rod, area of maximum blade)
A _c perimeter area of equivalent cone
A _e Equivalent penetration cross section of a bladed cone
The sum of Mitsuke (projected) area of the A _t rod area and a maximum of feathers
A _w A total of the blade area of the cone with a blade
dA _w The small area of the blade of the cone with a blade
A _pw summation of the projected area of the vanes with a vane
Small projection area of dA _pw bladed cone blade
D _o rod diameter (maximum diameter of cone)
D _w Maximum blade diameter
Energy input by penetration per E _i rotation
E _c Energy consumed by penetration per revolution
Energy consumed per revolution by E _s vertical penetration
Energy consumed per revolution due to E _μ rotational friction
Energy consumed per revolution due to penetration friction associated with E _μp rotation
Energy consumed per rotation due to blade friction accompanying E _μa rotation
A value obtained by converting F _p penetration friction resistance torque T _b (equivalent working radius r _e ') into friction force at blade working resistance f _w equivalent working radius r _w '
F _w Blade friction resistance
dF _w circumferential component of blade friction stress caused by blade
F _{μp Perpendicular} friction force generated by vertical penetration resistance (total force of friction)
The value obtained by replacing the acting torque acting on the H _t bladed cone with the horizontal force on the equivalent acting circle of the blade propulsion force = T _b / r _w '
l Spiral length of the central part of the blade per rotation
L _b action vertical force
N N value
P blade pitch (the amount of movement in the Z direction while the blade makes one revolution)
P _w blade propulsion
P _a wedge effect by the maximum radius of the vertical stress intensity q _c cone penetration resistance r _o cone shaft which acts on the conical peripheral surface as the blade propulsion Stress p _p penetration resistance acting on the wing upper surface (the radius of the rod, the maximum inner diameter of the blade )
r _e Equivalent penetration radius r _e 'of the bladed cone equivalent operating radius r _w maximum radius r _{w of the} blade equivalent operating radius r _w ' of the blade frictional torque r _{w 1} 'in the case of one donut-shaped spiral blade Equivalent action radius r _wd 'Equivalent action radius of ring with outer diameter r _w ψ / (2 n π), inner diameter r _o ψ / (2 n π)
R _p vertical penetration resistance
s Vertical penetration amount per rotation
t Average thickness of the blade
T _b acting torque
Blade friction resistance torque by blade driving force in the case of one T _d donut shaped blade
Penetration frictional resistance torque generated by T _p vertical penetration resistance
Wings frictional resistance torque generated by the T _w wings propulsion
Blade friction resistance torque generated by blade thrust of dT _w minute element
The sum of earth removal volume and cone earth removal volume per rotation by V _w blades
Z vertical axis alpha q _c and R factor beta q _c and friction coefficient τ circumferential direction of the rotation angle μ ground and the blade inclination angle ψ polar microelements coefficient δ blade determined by the relationship between the N value determined by the relationship _p Friction stress degree θ Equivalent inclination angle of blade ω Angle from center axis of cone tip 羽根 Equivalent force of blade friction resistance torque Coordinate axis of circumferential direction η Equivalent action radius of penetration friction resistance torque (r _e ') and blade Ratio of equivalent action radius (r _w ') of frictional resistance torque

Although the embodiments of the present invention have been described above with reference to the drawings and formulas, the present invention is not limited to the illustrated examples, and design changes and applications normally made by those skilled in the art without departing from the technical concept thereof. It is mentioned just to include the range of variation.

DESCRIPTION OF SYMBOLS 1 bladed cone 2 cone part 2a cone outer peripheral surface 3 spiral blade part 4 cone tip 5 rod lower end 6 rod upper part 7 rod 8 construction machine 9 ground (ground to be surveyed)

Claims

A bladed cone having a cone portion decreasing in diameter toward the penetration direction and a spiral blade portion provided on the outer peripheral surface of the cone portion and having a width narrowed toward the tip; and a rod for attaching the bladed cone to the lower end The bladed cone is made to penetrate the ground to be surveyed by the load torque applied to the upper portion of the rod and the load vertical force, and based on the acting torque and the applied vertical force acting on the bladed cone, or to the bladed cone A ground investigation method, characterized in that the penetration resistance of the ground to be investigated is evaluated based on the acting torque, the acting vertical force, and the penetration amount per one rotation of the bladed cone.
[Correction based on rule 91 28.12. 2018]
In the case of evaluating the penetration resistance of the surveyed ground based on the acting torque acting on the bladed cone and the acting vertical force:
The ground investigation method according to claim 1, wherein the cone penetration resistance and the standard penetration test N value (hereinafter abbreviated as N value) are evaluated by the following formula.
Cone penetration resistance (q c ) = (T b C 2 / r w ′ + L b C 1 ) / (C 1 + C 2 μη / C 3 ) / (α A e )
N value = (T b C 2 / r w '+ L b C 1) / (C 1 + C 2 μη / C 3) / (αβA e)
C 1 = sin θ + μ cos θ, C 2 = cos θ−μ sin θ, C 3 = sin ω + μ cos ω
Action torque acting on T b bladed cone
L b Vertical force acting on the bladed cone r w 'Equivalent operating radius of blade frictional resistance torque η Equivalent operating radius of penetrating frictional resistance torque (r e ') and equivalent operating radius of blade frictional resistance torque (r w ') Ratio of friction coefficient of friction between ground and blade ω angle from center axis of cone tip θ equivalent inclination angle of blade
A e Determined from the relationship between the equivalent penetration cross section α q c of the cone with a blade and R p (vertical penetration resistance) Coefficient determined from the relationship between β q c and N value
In the case of evaluating the penetration resistance of the ground under investigation based on the acting torque acting on the winged cone, the acting vertical force, and the penetration amount per one rotation of the winged cone:
When the vertical penetration amount (s) per one rotation of the bladed cone is equal to or smaller than the blade pitch (P),
The ground investigation method according to claim 1, characterized in that the cone penetration resistance and the N value are evaluated by the following equation from the acting torque, the acting vertical force, and the amount of penetration per one rotation of the bladed cone.
Cone penetration resistance (q c ) = (2πT b + L b s + 2π μ w w L b / (C 2 cos θ)) / (s + 2πμ
r e ′ / C 3 + 2πμ r w ′ / (C 2 cos θ)) / (αA e )
N value = (2πT b + L b s + 2πμr w 'L b / C 2 cosθ) / (s + 2πμr e' / C 3 + 2πμr w '/ (C 2 cosθ)) / (αβA e)
C 2 = cosθ-μsinθ, C 3 = sinω + μcosω
Action torque acting on T b bladed cone
L b Vertical force acting on a bladed cone
s Vertical penetration amount r w 'per equivalent rotation radius Equivalent radius of action of blade friction torque r e ' Equivalent friction radius of penetration friction torque μ Friction coefficient of ground and blades ω Angle from center axis of cone tip θ equivalent of blades Angle of inclination
A e Determined from the relationship between the equivalent penetration cross section α q c of the cone with a blade and R p (vertical penetration resistance) Coefficient determined from the relationship between β q c and N value
In the case of evaluating the penetration resistance of the ground under investigation based on the acting torque acting on the winged cone, the acting vertical force, and the penetration amount per one rotation of the winged cone:
When the vertical penetration amount (s) per one rotation of the bladed cone is larger than the blade pitch (P),
The ground investigation method according to claim 1, characterized in that the cone penetration resistance and the N value are evaluated by the following equation from the acting torque, the acting vertical force, and the amount of penetration per one rotation of the bladed cone.
Cone penetration resistance (q c ) = (2πT b + L b s) / (s + 2π μ r e '/ C 3 ) / (α A e )
N value = (2πT b + L b s) / (s + 2π μ r e '/ C 3 ) / (αβ A e )
C 3 = sin ω + μ cos ω
Action torque acting on T b bladed cone
L b Vertical force acting on a bladed cone
s Vertical penetration amount per rotation r e 'Penetration friction resistance torque equivalent action radius μ Coefficient of friction between ground and blade ω Angle from the center axis of cone tip θ Angle tilt angle of blade
A e Coefficient determined from the relationship between the equivalent penetration cross section α q c of the cone with a blade and R p (vertical penetration resistance) Coefficient determined from the relationship between β q c and the N value
The bladed cone used in the ground survey method according to any one of claims 1 to 4, wherein the cone portion reduces in diameter toward the tip, and the outer periphery of the cone portion is provided with a width toward the tip A bladed cone characterized by comprising:
The bladed cone according to claim 5, wherein a blade pitch of the bladed cone is 0.5 to 1.5 times the outermost diameter of the cone.