JP2014109158A - Slope reinforcement method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a slope reinforcement method which alleviates stress concentration on the vicinity of a connection part between a precast plate and a rod-shaped reinforcement material, and which prevents a slope in a state of excavation without shoring from collapsing, even in the case of a sharp slope.SOLUTION: An axial force Facting on a rod-shaped reinforcement material 7 is adjusted by a tightening force T of a nut 8 in a nut tightening step. Thus, stress concentration on the vicinity of a connection part can be alleviated by ground reaction on the side of a slope 2, which is generated by pressing precast plates 1, 1a... against the slope 2 by the axial force F. This can inhibit deformation on the side of the slope 2.

Description

  The present invention relates to a method for reinforcing a slope, that is, a natural steep slope or a cut slope.

  The applicant of the present application, as a reinforcement method for stabilizing the slope, is to install the precast plate by screwing and tightening a nut to the protruding end portion of the rod-shaped reinforcing member that penetrates the precast plate and is fixed in the ground state. We have a patent on the so-called “reverse winding construction” performed from the upper stage to the lower stage, which basically consists of the process of installing the precast plates 1, 1a... On the slope 2 formed by excavation as shown in FIG. A step of penetrating the central hole of each precast plate 1, 1a ... and drilling it on the slope 2 side, a step of injecting the grout material 6 into the hole portion 5 formed in the drilling step, and a grout material injection There are a step of inserting the rod-shaped reinforcing material 7 into the drilling portion 5 either before or after the step, and a step of screwing and tightening the nut 8 to the protruding end portion of the rod-shaped reinforcing material 7 after curing and hardening of the grout material 6. 1st stage precast board 1, 1a Is formed by excavating and forming a step portion 9 at a lower portion thereof, and precast plates 1, 1 a... Are arranged in parallel on the step portion 9 by the steps after the precast plate installation step. 2 is fixed to the second stage, and the next slope 2 is formed by excavating the second slope 2 at a height from which the precast board 1, 1a... Can be installed, and the next stage 9 is formed. , 1a... Are suspended from the first-stage precast plate 1, 1a, and then the second-stage precast plates 1, 1a,. A reinforcing slope having a precast plate in a plurality of stages can be formed, and a pile body 10 adapted to the ground is formed by the rod-shaped reinforcing material 7 and the hardened grout material 6 (see, for example, Patent Documents 1 to 3).

Japanese Patent Publication No. 7-26402 Japanese Patent No. 2530565 Japanese Patent No. 5065227

However, the above-described prior art has a problem to be solved as described below.
(1) In order to install the precast plates 1, 1a, etc. in the next stage, a slope 2 in an unearthed state is generated for a certain period of time, and the precast plates 1, 1a, etc. in the previous stage have no support and are intended to descend due to their own weight. As a result, stress is concentrated in the vicinity of the connecting portion between the precast plates 1, 1 a... And the rod-shaped reinforcing material 7, and an excessive shearing force acts near the fixing portion of the rod-shaped reinforcing material 7. 1 and 1a are generally suspended from the upper precast plates 1 and 1a, and the load suspended by 71 rod-shaped reinforcing members is equivalent to two precast plates 1 and 1a, and the load is further increased. Therefore, a base auxiliary pile is placed between the precast plates 1, 1a ... and the slope 2 to support the self-weight of the precast plates, or the installation interval of the rod-shaped reinforcing materials is narrowed to increase the number of reinforcing materials. To reduce the force acting on each reinforcing material Te necessity of corresponding, resulting process and amount of work and workability is deteriorated increases.
(2) The slope 2 of the bare digging state has a higher risk of collapsing as it becomes steep, and once the collapse occurs, the precast plates 1, 1a, etc. that have already been installed will sink greatly, causing stress concentration near the connecting part. It gets bigger.

  In view of the problem that the present invention is based on the above-mentioned prior art, the stress tends to concentrate in the vicinity of the connecting portion between the precast plate and the rod-shaped reinforcing material, and the slope of the unexcavated state tends to collapse as the slope becomes steep. A reverse winding method in which the precast plate is installed from the upper stage to the lower stage by screwing and tightening a nut to the protruding end of the bar-shaped reinforcement fixed in the ground state, and the axial force acting on the bar-shaped reinforcement By adjusting the tightening force of the nut in the nut tightening step, it is possible to relieve stress concentration in the vicinity of the connecting portion by the ground reaction force on the slope side caused by pressing the precast plate against the slope by this axial force. Thus, the deformation on the slope side can be suppressed to solve the above problem.

In short, the present invention is a reverse winding construction method in which the precast plate is installed from the upper stage to the lower stage by screwing and tightening a nut to the protruding end portion of the rod-shaped reinforcing member that is penetrated through the precast plate and fixed in the ground state. By adjusting the axial force acting on the rod-shaped reinforcing material by the tightening force of the nut in the nut tightening step, the ground reaction force on the slope side generated by pressing the precast plate against the slope by this axial force is connected by Since the stress concentration in the vicinity of the part can be relaxed, it is possible to completely prevent the downward shift due to the weight of the precast plate, and to suppress the sliding force of the slope and local deformation of the soil. It is possible to maintain the slope of this as it is.
However, by using a precast plate, the slope work can be completed for each step of reverse winding, so that a tightening force can be applied to the bar-shaped reinforcing material for each step during construction. Force can be generated effectively.

In addition to the weight of the precast plate, the angle θ of the resultant force _Fsum of F _X and F _Y is calculated by dividing each vector of acting force acting during construction into X component (horizontal component) and Y component (vertical component) , The tightening force and the slope of the inclined surface so that the angle (ω−90 °) of the main collapse angle ω is θ = tan ⁻¹ (F _Y / F _X ) ≧ (ω−90 °). The reverse winding excavation height is determined, and the resultant force is the resultant force of axial force, anti-trapping effect force, moving clot weight, precast plate weight, precast plate back friction force and ground arch force. For example, the tightening force and the reverse winding excavation height of the slope can be determined naturally, and the practical effect is significant.

It is sectional drawing which shows the state before installing the precast board of the next step by the slope reinforcement construction method which concerns on this invention. It is a figure showing the direction of the acting force in the state of FIG.

The slope reinforcing method according to the present invention is the reverse winding construction method similar to the above prior art, specifically, the step of installing the precast plates 1, 1a ... on the slope 2, the back side and the slope of the precast plates 1, 1a ... 2, the step of injecting the backfill material 4 into the gap between the two, the step of drilling the precast plates 1, 1 a... To the slope 2 side, and the inside of the drilled portion 5 formed by this drilling step. The step of injecting the grout material 6, the step of inserting the rod-shaped reinforcing material 7 into the drilled portion 5 either before or after the grout material injecting step, and the curing of the bar-shaped reinforcing material 7 after curing and hardening of the grout material 6. The nut 8 is screwed and tightened to the projecting end, and the nut 8 is tightened with a predetermined tightening force T in the screwing and tightening process of the nut 8 according to the ground constant and gradient to be installed. 7 to confer predetermined axial force F _t, pressing a precast plate 1, 1a ... to slope 2, The precast plates 1, 1a ... are converted into a resultant force in the direction of the natural ground by synthesizing the acting force (self-weight) of the precast plates 1, 1a ... A reaction force acts between the butt and the bottom of the soil to suppress local deformation of the soil and stabilize the excavated surface in the bare digging state.

  In addition, by bringing the vector direction of the resultant force closer to the axial direction of the rod-shaped reinforcing member 7, it is possible to relax the stress concentration acting in the vicinity of the connecting portion, and the direction of the resultant force is the main collapse angle ω. On the other hand, if the tightening force and reverse winding excavation height are determined so as to be higher than the reference line BL of the inclination angle (ω-90 °) at right angles, the sliding force of the slope 2 can be suppressed, and the entire slope 2 is stabilized. Can be kept to the side.

For example, the force vector acting at the time of construction is shown in FIG. 2 (only the direction is explained, and the magnitude of each vector is not based on the actual value), and the resultant force F of all the vectors _Sum can be calculated by the following equation (1), where F _X and F _Y are obtained by dividing each vector into an X component (horizontal component) and a Y component (vertical component).

F _sum = √ (F _X ² + F _Y ² ) (1)

Further, the direction angle θ of the resultant force F _sum can be calculated by the following equation (2) using the above F _X and F _Y.

θ = tan ⁻¹ (F _Y / F _X ) (2)

  If the relationship between θ and (ω−90 °) calculated by the above equation (2) is θ ≧ (ω−90 °), the local excavation surface of the unearthed digging is suppressed while suppressing local deformation of the soil. It is possible to relax the stress concentration acting on the panel and the reinforcement connecting part, while keeping it on the safe side. When θ <(ω−90 °), the force to slide along the main decay line acts. To come.

Specifically, F _X and F _{Y in the} expressions (1) and (2) are the axial force F _t that can be calculated using the following expressions (3) to (7), and the force F _{n of the} detent effect. It is calculated by adding the X component and the Y component of the moving clot weight W _s , the precast plate weight W _p , the precast plate back friction force F _f , and the ground arch force F _g .

  The “strengthening effect force” refers to a force acting on the pile body 10 that prevents the main active area block from sliding.

  The “moving clot weight” refers to the weight of the clot in the active region per length of the precast plate 1, 1a.

“Ground arch force” is the distance between the back of the precast plates 1 and 1a, where the effect of tightening is exerted by applying axial force to the reinforcing material from the tip to the sliding force in which the main area in the natural ground tries to slide. over the arch structure is formed a force resisting against landslides, in the present invention, the ground arch force, vertical main acting counter-wound excavation height H働土pressure merging force and reinforcement fixing axial force F _t It refers to the ground reaction force generated by the combined force of the bousinesque.
However, in order to stabilize the part that has been subjected to surface deformation and restraint by the precast plates 1 and 1a and the rod-shaped reinforcing member 7, only the main earth pressure of the slope 2 in the unexcavated state that has been excavated in reverse is considered. Yes.
The direction of the ground arch force is the arch tangent at the intersection of the main failure line where the stress in the mass is concentrated and the ground arch, and the angle formed with the horizontal plane is the same as the main failure angle ω.

“Ground constant” includes unit volume weight γ (kN / m ³ ), internal friction angle φ (°), adhesive force C (kN / m ² ), and main collapse angle ω (°).
“Internal friction angle φ” is a component of soil shear strength, and the frictional resistance caused by the internal friction of soil particles is generally proportional to the normal stress acting on the shear surface, and the proportionality constant is tan φ. The angle φ.
“Adhesive strength C” is a principal stress in clay or the like, that is, a force that resists shearing even when drag = 0, and Coulomb's equation “τ = C + p × tanφ (p: normal stress) indicating the shear strength τ of soil. ) ”Is a portion indicated by“ C ”.
The “main failure angle ω” is the minimum value of the earth pressure that can be achieved in a state where the earth mass does not break. If the earth pressure tries to become smaller than this, the earth mass will undergo the main failure, and the slip surface at that time The angle is calculated as ω = 45 ° + φ / 2.

  And, as a method of deriving “inner friction angle φ” and “adhesive strength C”, a mechanical test of soil samples such as a uniaxial compression test, a triaxial compression test, a single shear test, a torsional shear test, A resistance device is installed at the tip of the rod, and this is inserted into the ground. Sounding to check the soil properties by penetration and rotation, past survey data and statistically analyzed data (for example, “Ground for building standard design” There are methods to set based on the survey plan guideline ”), and so on.

[Calculation formula of axial force F _t (kN)]

F _t = T / (k × d) (3)
T: Tightening force (N · m), k: Torque coefficient, d: Screw diameter (m)

[Calculation formula of the force F _n (kN) of the retaining effect]

F _n = A _P × q _d (4)
A _P : resistance area (m ² ) = diameter B (m) of the pile body 10 × length L of the pile body 10 in the active region
The projected area of the pile 10 located in the main working area.
q _d : Ultimate bearing stress (kN / m ² )
The maximum load or load strength that the ground can support without causing shear failure.
q _d = C · N _C + q · N _q + (γ · B / 2) · Nγ
N _C , N _q , Nγ: bearing capacity coefficient (substitute from the bearing capacity coefficient table of Tertzagi in Table 1 below)
q = γ · D _f
D _f : Soil cover (m)
Soil cover thickness for pile body 10 located in the main working area.

[Calculation formula for moving soil mass W _s (kN)]

W _s = S × b × γ (5)
S: Moving mass block cross-sectional area (m ² ), b: Precast board width (m)

[Calculation formula for precast plate back friction force F _f (kN)]

F _f = μ × (F _t + W _p · sin | α |) (6)
μ: Friction coefficient of slope (= tan φ), α: Angle of rod-shaped reinforcing material 7 (°)

[Grand arch force: Formula for F _g (kN)]

F _g = [(γ × H ² × K _a ) / 2-2 × C × H × √ (K _a ) + (σ _zu + σ _zd ) × H / 2] × b
...... (7)
H: Reverse winding excavation height (m)
K _a : main earth pressure coefficient (= tan ² (45 ° −φ / 2))
γ × H ² × K _a / 2-2 × C × H × √ (K _a ): active earth pressure combined force σ _zu : vertical stress due to Boussinesq on the upper side of reverse winding excavation σ _zu = 3 × F _t × sin | α ｜ / (2 × π × z ² )
σ _zd : Vertical stress due to Boussinesque under the reverse winding excavation σ _zd = 3 × F _t × sin | α | / [2 × π × (z + H) ² ]
z: Vertical height (m) from the connection point between the rod-shaped reinforcing member 7 and the precast plates 1, 1a ... to the lower end of the precast plates 1, 1a ...

In other words, the only variables due to construction are “reverse winding excavation height H” and “reinforcement anchoring axial force F _t ”, and other factors are values determined by ground constants, product specifications, or “H” and “F _t ”. It is.

(A) Ground constant γ = 18kN / m ³
φ = 30 °
C = 0kN / m ²
in the case of,
ω = 45 ° + 30 ° / 2 = 60 °
It becomes.

(B) Used material precast plate 1, 1a ...
Weight W _p = 8kN
Vertical width a = 1.2m
Width b = 1.8m
Thickness t = 0.12m
Slope 2 angle β = 73.3 ° (slope gradient 1: 0.3)

Rod-shaped reinforcement 7
Type: D29
Length: 5m (end screw processing)
Screw diameter d = 0.027m (M27)
Pile 10 diameter B = 0.09m
Placing angle α = −16.7 ° (343.3 °)
Length L of pile 10 in the main working area = 0.5m

(C) Temporary setting of construction conditions Lower precast plates 1, 1a, etc. are suspended, and construction at an excavation height H of 1.3 m is examined.

(D) Verification [Axial force F _t ]
Substituting d = 0.027 m and torque coefficient k = 0.2 into the above equation (3),
F _t = 0.186 · T (kN)
It becomes.

[The Power of detained effect F _n]
Substituting B = 0.09m and L = 0.5m into the following equation,
Resistance area A _P (m ² ) = B × L = 0.045 m ²
Moreover, if the earth covering D _f = 0.6 m,
q = γ · D _f = 18 × 0.6 = 10.8 kN / m ²
It becomes.
Since C = 0 kN / m ² , γ = 18 kN / m ³ , B = 0.09 m, and φ = 30 °, according to Table 1, N _C = 37.2, N _q = 22.5, Nγ = 20 0.
Therefore, if these are substituted into the following equation,
Ultimate bearing stress q _d (kN / m ² )
= C · N _C + q · N _q + (γ · B / 2) · Nγ
= 0 × 37.2 + 10.8 × 22.5 + (18 × 0.09 / 2) × 20.0
= 259.2kN / m ²
It becomes.
Substituting the above A _P and q _d into the above equation (4),
F _n = 11.664 (kN)
It becomes.
[Precast plate weight W _p]
Assuming the state where the precast board is suspended,
W _p = 8 kN × 2 sheets = 16 (kN)
It becomes.

[Movement mass weight W _s ]
When the moving mass sectional area S = 0.77 m ² and b = 1.8 m and γ = 18 kN / m ³ are substituted into the above equation (5),
W _s = 24.948 (kN)
It becomes.

[Precast plate back friction force F _f ]
Since W _p = 16 kN and μ = tan φ = tan 30 ° = 0.777, when these are substituted into the above equation (6),
F _f = 0.577 · F _t +2.653 (kN)
It becomes.

[Ground arch force F _g ]
H = 1.3m
K _a = tan ² (45 ° −φ / 2)
= Tan ² 30 °
= 0.333
for,
Main earth compaction force = γ × H ² × K _a / 2-2 × C × H × √ (K _a )
= 18 × 1.3 ² × 0.333 / 2-2 × 0 × 1.3 × √0.333
= 5.065

When z = 0.575m,
σ _zu = 3 × F _t × sin | α | / (2 × π × z ² )
= 3 × F _t × 0.287 ÷ (2 × π × 0.575 ² )
= 0.415 · F _t (kN / m ² )
σ _zd = 3 × F _t × sin | α | / [2 × π × (z + H) ² ]
= 3 × F _t × 0.287 ÷ (2 × π × 1.875 ² )
= 0.039 · F _t (kN / m ² )
It becomes.

And if these are substituted into the above equation (7),
F _g = 9.117 + 0.531 · F _t (kN)
It becomes.

Therefore, if F _X that is the X component of the resultant force F _sum is calculated,
F _x = F _t × cos 343.3 ° + F _n × cos 90 ° + W _p × cos 270 ° + W _s × cos 270 ° + F _f × cos 73.3 ° + F _g × cos 120 °
= 0.858 · F _t -3.797 (kN)
And calculating the Y component, F _Y ,
F _Y = F _t × sin 343.3 ° + F _n × sin 90 ° + W _p × sin 270 ° + W _s × sin 270 ° + F _f × sin 73.3 ° + F _g × sin 120 °
= 0.726 · F _t -18.847 (kN)
It becomes.

Substituting the above F _X and F _Y into the above equation (2),
θ = tan ⁻¹ (0.726 · F _t −18.847) / (0.858 · F _t −3.797)
That is, tan θ = (0.726 · F _t -18.847) / (0.858 · F _t −3.797)
And
ω-90 ° = 60 ° -90 ° = -30 °
It is.
Therefore,
tan θ ≧ tan (−30 °) = − 0.577
so,
(0.726 · F _t -18.847) / (0.858 · F _t -3.797)
≧ −0.577
So that
T ≧ 92.634 (N · m)
Thus, the tightening force T is equal to or greater than the calculated value.

In addition, when working at T = 100 (N · m) within the above range, it is clear that the angle θ of the resultant force F _sum is larger than (ω−90 °).
F _t = 18.6 (kN)
Become
F _X = 0.858 · F _t −3.797 (kN) = 12.262 (kN)
F _Y = 0.726 · F _t -18.847 (kN) = − 5.343 (kN)
Therefore, if these are substituted into the above equation (1),
F _sum = √ (12.162 ² + (− 5.343) ² )
= 13.284 (kN)
It becomes.

1, 1a ... Precast plate 2 Slope 7 Bar-shaped reinforcement 8 Nut F _f Precast plate back friction force F _g Ground arch force F _n Anti-faulting force F _t Axial force F X component of _X resultant force F Y component of _Y resultant force F _sum Combined force H Reverse winding excavation height T Tightening force W _p Precast plate weight W _s Moving mass weight θ Direction angle of resultant force ω Main collapse angle

Slope present invention is based on the prior art, it is easy to stress concentration in the connecting portion near the precast plate and the rod-shaped reinforcing member, and the slope of the dug state that light of likely problems to collapse about steepens, was drilled formed Before and after the process of installing the precast plate, the step of penetrating each precast plate and drilling on the slope side, the step of injecting the grout material into the entire hole formed in the drilling step, and the grout material injection step A step of inserting a rod-shaped reinforcing material into the drilled hole portion and a step of screwing and tightening a nut to the protruding end portion of the rod-shaped reinforcing material after curing and hardening of the grout material. Excavating and forming a slope with a height that can be juxtaposed, forming a step at the bottom, fixing a precast plate on the step and fixing it to the slope by the steps after the precast plate installation step, and then To the second stage After excavating and forming the next slope with a height enough to install the recast plate, the second stage is suspended by placing the precast plate on the first precast plate. This is a reverse winding method that repeats the third and subsequent stages of fixing the precast plates in parallel and fixing , and adjusting the axial force acting on the rod-shaped reinforcing material by the tightening force of the nut in the nut tightening step. The slope side ground reaction force generated by pressing the precast plate against the slope by the axial force can alleviate stress concentration in the vicinity of the connecting portion, thereby suppressing the deformation on the slope side and solving the above problems. .

In short, the present invention includes a step of installing a precast plate on an excavated slope, a step of penetrating each precast plate and drilling holes on the slope side, and injecting grout material into the entire drilling portion formed in the drilling step. A step of inserting the rod-shaped reinforcing material into the drilled hole part before or after the grout material injecting step, and a step of screwing and tightening a nut to the protruding end portion of the rod-shaped reinforcing material after curing of the grout material. And having a step portion formed at the lower portion thereof by excavating and forming a slope having a height that allows the first-stage precast plates to be juxtaposed. The process is fixed to the slope, and then the next slope from which the precast plate can be installed is excavated and formed in the second stage from the top to form the next stage, and the precast board is precast in the second stage. Hanging on the board After, a counter-wound construction methods repeated the third stage after that in the same manner as first stage second stage of the pre-cast plate parallel to the fixing, the axial force acting on the rod-shaped reinforcing member, a nut in the nut tightening step By adjusting the tightening force, the stress reaction in the vicinity of the connecting portion can be mitigated by the ground reaction force on the slope side caused by pressing the precast plate against the slope by this axial force. The downward displacement can be completely prevented, and the sliding force of the slope and the local deformation of the soil can be suppressed, so that the slope of the bare digging state can be maintained as it is.
However, by using a precast plate, the slope work can be completed for each step of reverse winding, so that a tightening force can be applied to the bar-shaped reinforcing material for each step during construction. Force can be generated effectively.

However, the above-described prior art has a problem to be solved as described below.
(1) In order to install the precast plates 1, 1a, etc. in the next stage, a slope 2 in an unearthed state is generated for a certain period of time, and the precast plates 1, 1a, etc. in the previous stage have no support and are intended to descend due to their own weight. As a result, stress concentrates in the vicinity of the connecting portion between the precast plates 1, 1 a... And the pile body 10, and an excessive shearing force acts near the fixing portion of the pile body 10 . 1a ... is usually suspended from the upper precast plate 1, 1a ... The load that one of the piles 10 suspends is equivalent to two precast plates 1, 1a ... and the load is further increased. Therefore, a base auxiliary pile is placed between the precast plate 1, 1a ... and the slope 2 to support the weight of the precast plate, and the installation interval of the rod-shaped reinforcing material is narrowed to increase the number of pile bodies 10. Need to respond by reducing the force acting on each pile 10 As a result, the process and the amount of work increase, resulting in poor workability.
(2) The slope 2 of the bare digging state has a higher risk of collapsing as it becomes steep, and once the collapse occurs, the precast plates 1, 1a, etc. that have already been installed will sink greatly, causing stress concentration near the connecting part. It gets bigger.

In view of the problem that the present invention is based on the above prior art, stress is likely to concentrate in the vicinity of the connecting portion between the precast plate and the rod-shaped reinforcing material, and the slope in the unexcavated state tends to collapse as the slope becomes steep. Before and after the process of installing the precast plate, the step of penetrating each precast plate and drilling on the slope side, the step of injecting the grout material into the entire hole formed in the drilling step, and the grout material injection step A step of inserting a rod-shaped reinforcing material into the drilled hole portion and a step of screwing and tightening a nut to the protruding end portion of the rod-shaped reinforcing material after curing and hardening of the grout material. Excavating and forming a slope with a height that can be juxtaposed, forming a step at the bottom, fixing a precast plate on the step and fixing it to the slope by the steps after the precast plate installation step, and then To the second stage Rekyasuto plate installation can backwound the next slope excavation height drilling formed to form the next stage unit, after placing suspended precast plate precast plate of the first stage to the second stage, like the first stage It is a reverse winding method that repeats the third and subsequent stages of fixing the second stage precast plate in parallel and fixing , and in the upper stage precast plate when the lower stage precast plate is suspended, the rod-shaped reinforcing material and the hardened grout the axial force acting on the pile body formed by wood, slant side caused by pressing the precast plate slopes in axial force acting on the pile body by tightening of the nut in the nut tightening step at the upper precast plate of the ground reaction force, the slope of the dug state and enables maintenance so as not to collapse in the slope reinforcing construction method to alleviate the stress concentration near a connection part, wherein Attaching force and reverse-winding excavation height of the slope, in addition to the weight of the two precast plates, each of the axial force acting at the time of construction, the force of the retaining effect, the weight of the moving clot, the friction force of the back surface of the precast plate and the ground arch force Is divided into an X component (horizontal component) and a Y component (vertical component), and an angle θ of the resultant force F _sum of F _X and F _Y and an angle (ω−90 °) in the direction perpendicular to the main decay angle ω. ) Is determined so that θ = tan ⁻¹ (F _Y / F _X ) ≧ (ω−90 °), and the force of the anti-traction effect is a pile that prevents the main active mass from trying to slide. The weight of the moving clot is the weight of the clot in the main working area per length of the precast plate, and the ground arch force is the sliding force that the main working area in the natural ground tries to slide. Tightening by applying axial force to the pile body from the law By forming an arch structure between the back surfaces of the precast plate that exerts a beating effect and resisting the slope collapse, the deformation on the slope side can be suppressed, and the above-described problems are solved.

In short, the present invention includes a step of installing a precast plate on an excavated slope, a step of penetrating each precast plate and drilling holes on the slope side, and injecting grout material into the entire drilling portion formed in the drilling step. A step of inserting the rod-shaped reinforcing material into the drilled hole part before or after the grout material injecting step, and a step of screwing and tightening a nut to the protruding end portion of the rod-shaped reinforcing material after curing of the grout material. And having a step portion formed at the lower portion thereof by excavating and forming a slope having a height that allows the first-stage precast plates to be juxtaposed. The process is fixed on the slope, and then the next slope of the reverse winding excavation height that allows the precast board to be installed in the second stage from the top is excavated to form the next stage, and the precast board is the first stage in the second stage. On the precast board After lowering disposed Ri, the first stage as well as parallel precast plate of the second stage, a reverse-wound construction methods to repeat the third stage subsequent to fixing, the upper precast at the stage in which suspended lower precast plate wherein in the plate, the axial force acting on the pile body formed by grout cured with the bar reinforcement by tightening the nut in the nut tightening step at the upper precast plates in axial force acting on the pile body the ground reaction force slope side caused by pressing the precast plate slope, the slope of the dug state and enables maintenance so as not to collapse, since the stress concentration near a connection part, the lower due to the weight of the precast plate The displacement can be completely prevented, and the sliding force of the slope and local deformation of the soil can be suppressed. It can be maintained in the state.
However, by using a precast plate, it is possible to apply a tightening force to the pile body every time one stage of construction is completed by completing the slope work for each stage of reverse winding. Can be generated effectively.

In addition to the self-weight of the two precast plates , the tightening force and the reverse winding excavation height of the slope include the axial force acting at the time of construction, the force of the retaining effect, the weight of the moving clot, the friction force of the back surface of the precast plate and the ground arch force . Each vector is divided into an X component (horizontal component) and a Y component (vertical component), and an angle θ of a resultant force _Fsum of F _X and F _Y and a perpendicular angle (ω−90) of the main decay angle ω. Is determined so that θ = tan ⁻¹ (F _Y / F _X ) ≧ (ω−90 °), and the force of the detent effect is to prevent the active region soil mass from attempting to slide, The force acting by the pile body is the weight of the moving mass, the mass of the mass within the main working area per length of the precast plate, and the ground arch force is the precast plate back friction force and the main ground Is there a tip for the sliding force that the working area tries to slide? , Since the force of resistance to the arch structure is formed landslides toward between the back of the precast plate effect clamping by applying axial force to the pile body is exhibited, by entering a number of provisions, naturally the The practical effect of the tightening force and the reverse winding excavation height of the slope can be determined.

The slope reinforcing method according to the present invention is the reverse winding construction method similar to the above prior art, specifically, the step of installing the precast plates 1, 1a ... on the slope 2, the back side and the slope of the precast plates 1, 1a ... 2, the step of injecting the backfill material 4 into the gap between the two, the step of drilling the precast plates 1, 1 a... To the slope 2 side, and the inside of the drilled portion 5 formed by this drilling step. The step of injecting the grout material 6, the step of inserting the rod-shaped reinforcing material 7 into the drilled portion 5 either before or after the grout material injecting step, and the curing of the bar-shaped reinforcing material 7 after curing and hardening of the grout material 6. Although and a threaded fitting tightening process of the nut 8 to the projecting end, the soil constants and the gradient of installation target, and tightening the nut 8 with a predetermined clamping force T at threaded fitting tightening process of the nut 8 Kuitai 10 to to confer predetermined axial force F _t, pressing a precast plate 1, 1a ... to slope 2, Pureki By converting the acting force (self-weight) that strikes plate 1, 1a ... to sink vertically into the resultant force that is combined with the axial force and goes toward the inside of the natural ground, the back surface and slope 2 of precast plate 1, 1a ... A reaction force acts between the butt and the bottom of the soil to suppress local deformation of the soil and stabilize the excavated surface in the bare digging state.

If the relationship between θ and (ω−90 °) calculated by the above equation (2) is θ ≧ (ω−90 °), the local excavation surface of the unearthed digging is suppressed while suppressing local deformation of the soil. It is possible to relax the stress concentration acting on the vicinity of the connection part between the panel and the pile body 10 while keeping it on the safe side, and when θ <(ω−90 °), it is the force that tries to slide along the main failure line Comes to work.

“Ground arch force” is the distance between the back of the precast plates 1 and 1a, where the effect of tightening is exerted by applying axial force to the reinforcing material from the tip to the sliding force in which the main area in the natural ground tries to slide. over the arch structure is formed a force resisting against landslides, in the present invention, the ground arch force, vertical main acting counter-wound excavation height H働土pressure merging force and reinforcement fixing axial force F _t It refers to the ground reaction force generated by the combined force of the bousinesque.
However, in order to stabilize the part that has been deformed and constrained by the precast plates 1, 1 a, and the pile body 10, only the main earth pressure on the slope 2 of the unexcavated slope 2 is considered. .
The direction of the ground arch force is the arch tangent at the intersection of the main failure line where the stress in the mass is concentrated and the ground arch, and the angle formed with the horizontal plane is the same as the main failure angle ω.

Claims (3)

It is a reverse winding construction method in which the installation work of the precast plate is carried out from the upper stage to the lower stage by screwing and tightening the nut to the projecting end portion of the rod-shaped reinforcing material that is penetrated through the precast plate and fixed in the driven state.
By adjusting the axial force acting on the rod-shaped reinforcing material by the tightening force of the nut in the nut tightening step, the ground side reaction force on the slope side generated by pressing the precast plate against the slope by this axial force, the connecting portion A slope reinforcement method characterized by the ability to alleviate stress concentration in the vicinity. In addition to the weight of the precast plate, the angle θ of the resultant force _Fsum of F _X and F _Y is calculated by dividing each vector of acting force acting during construction into X component (horizontal component) and Y component (vertical component) The angle (ω−90 °) in the direction perpendicular to the main decay angle ω is
θ = tan ⁻¹ (F _Y / F _X ) ≧ (ω−90 °)
The slope reinforcing method according to claim 1, wherein the tightening force and the reverse winding excavation height of the slope are determined so that 3. The slope reinforcing method according to claim 2, wherein the resultant force is an axial force, a force of a retaining effect, a moving clot weight, a precast plate weight, a precast plate back friction force and a ground arch force.

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