Stazhevsky Turning Anchors Presentation

8/7/2019 Stazhevsky Turning Anchors Presentation

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Where ground anchors are needed


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Anchorage work conditions

Installation of anchors is often done inadverse conditions :

remote, out-of-the-way (difficult-to-access)and confined places, e.g., vertical walls or

high steep slopes; at low air temperature etc.


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Requirements to ground anchors:

low number per area unit, high bearing capacity; simple design and high reliability;

low cost;

high installation productivity; no use of wet processes or self-consolidating

compounds in installation operations;

possibility of use of low-weight, maneuverable,

mobile devices, e.g., hand-held tools or portablemachines.


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Dilatancy anchors


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d

d

d+2d

F

Stressed-strained state of anchor lock

F


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Design versions of turning anchor

with flexible pull element


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u*

1

2

3

1

12

2

F F

4

a

b c

u*

1

2

3

1

12

2

F F

4

a

b c

) test bench;

) initial position of anchor plate;

) final position of anchor plate .

1 anchor plate,2 pull rope,

3 load gauge,

4 cavity

Laboratory tests


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F


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F


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F


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F


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A

F

Anchor plate kinematics

with central fixation of pull rope

(s = 0)

Hole axis

Trajectory of point A

0

x

x

u


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B

F

s 0

u

xA

x1

x2

Anchor plate kinematics with eccentric fixation of pull rope

(s > scr)

F pull out force; plate turn angle; x1 , x2 lateral drift of plate;

A anchor plate center; B rope fixation point;

s rope fixation point eccentricity.

Hole

axisTrajectory of point A

Hole axis


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Turn anchor load and kinematic diagrams

obtained in laboratory tests


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f

F

Increase in anchor bearing capacity at the expense of Euler forces

F = fek , where k friction factor


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Automated anchor test equipment

Schematic diagram

General view

1 hydraulic jack with hollow push rod;

2 anchor pull rope; 3 rope grip;

4 auxiliary rope grip; 5 hydraulic pump


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Field tests of anchors

Loading of anchor and registrationof its load diagram

Driving of anchor withhydraulic impact tool


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Load diagrams of various types of anchors

Plate type anchor

27

T-shape anchor

Cylindrical anchor

20015010

s=0

20015010

s=0

130, l=260, s=0

Final position of anchor


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Conclusion

Requirements to anchors formulated.

Dilatancy anchors with flexible pull rod and increasingpull resistance found to comply with the requirements.

Such anchors design and installation procedures

developed.

The anchors tested in laboratory and field conditions.

Operability and efficiency of the anchors confirmed by

the tests.


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Stazhevsky Turning Anchors Presentation

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