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Anchors, anchors, soil nails, anchor pipes, no longer confused

2018-12-12

At the scene, it is generally considered that the drill holes are 150mm anchors, generally they have deep holes, thick steel bars, and prestressing. The soil nails are generally short, the hole diameter is 100mm, and only one steel bar is placed. However, what is the difference between anchors, anchor cables, soil nails and anchor pipes? I don`t know the classmates.

Anchor: A member that transmits tension to a stable rock formation. When a steel strand or a high-strength steel wire bundle is used as the rod material, it may also be referred to as an anchor cable. - "Technical Specifications for Building Slope Engineering" GB50330-2002

Anchor cable: When the anchor rod body is made of high-strength steel strand, it can be called anchor cable.

Soil anchor: A bolt anchored in a soil layer. - "Technical Specifications for Building Slope Engineering" GB50330-2002
A tension rod body composed of a steel bar or a steel strand disposed in a borehole and extending into a stable soil layer at the end and a grout in the hole. - "Technical Regulations for Building Foundation Pit Support" JGJ 120-99

Rock bolt: A bolt anchored in a rock formation. - "Technical Specifications for Building Slope Engineering" GB50330-2002

System anchor: In order to ensure the overall stability of the slope, the anchor group is arranged in a certain format on the slope. - "Technical Specifications for Building Slope Engineering" GB50330-2002
In order to stabilize the surrounding rock as a whole, a group of anchors arranged in a certain pattern on the periphery of the tunnel. --《Technical Specification for Anchor Shotcrete Support》GB50086-2001

Anchoring: Engineering measures to reinforce rock mass using anchors anchored in the surrounding rock or rock slope of the cavern. "Basic Terminology Standard for Geotechnical Engineering" GB/T 50279-98

Anchor retaining wall: cement rod or multi-strand wire rope is anchored in the rock as a tensile member to keep the wall stable and retain the retaining wall of the soil. "Basic Terminology Standard for Geotechnical Engineering" GB/T 50279-98

Soil nailing wall: The support structure consisting of the soil and the protective surface of the side wall of the foundation pit reinforced with soil nails. - "Technical Regulations for Building Foundation Pit Support" JGJ 120-99

Soil nail: It is based on the principle of the New Austrian tunnel law. In the slope formed by natural slope or excavation, the reinforced bar is placed horizontally in the in-situ rock and soil of the foundation pit and the concrete surface layer is set along the slope. In-situ reinforcement technology that improves the mechanical properties of the overall geotechnical system and improves the stability of slopes and foundation pits. - "Geotechnical Engineering Handbook" Lin Zongyuan Note, October 2005, 1st Edition
The soil nail can be regarded as a small-sized passive anchor (some similar to the full-length bonded anchor), which is divided into two types: bored grouting nail and nailing nail. The soil nailing material is angle steel, round steel and steel bar. Or steel pipe. - "Handbook of Geotechnical Anchorage Technology" Yan Moming, Xu Yuxiang, and Su Ziyi. The latter two participated in the preparation of the Technical Specification for Anchored Shotcrete Support GB50086-2001.

Anchor pipe: When the soil nailing rod body adopts a steel flower tube (that is, several grouting holes are drilled on the steel pipe), it can be called an anchor pipe.

the difference

The difference between soil nails and anchors is:
1. Stress mechanism
1) The soil nail is passively stressed, that is, after a certain deformation of the soil body, the soil nail is stressed, thereby preventing the soil from continuing to deform;
2) The anchor rod is actively stressed, that is, by pre-stressing the anchor rod, the excessive deformation of the soil body is restricted before the foundation pit is not excavated;

2, the range of force
1) The soil nail is full-length force, but the direction of the force is divided into two parts. The potential slip surface divides the soil nail into two parts. The direction of the first half is directed to the direction of the potential slip surface, and the back half is directed back by the force direction. In the direction of the potential slip surface;
2) The anchor is the free end of the front half and the forced section of the rear half, so sometimes the mortar is not filled in the front half of the anchor.
The above statement is the difference between the non-prestressed anchor and the prestressed anchor (cable).

3. The essential difference between the two is the difference in working mechanism
The soil nail is a soil reinforcement technology, which uses the densely arranged reinforced body as the soil reinforcement means to improve the strength and self-stability of the soil to be reinforced;
The anchor rod is an anchoring technology, and the load of the unstable rock mass in the surface layer is transmitted to the deep stable position of the rock and soil body through the tension rod, thereby realizing the stability of the rock mass to be reinforced.
When the soil is deformed, the soil nail provides resistance with this deformation, and the force characteristics are the same as those of the anchor. It's just that it's full length. The direction of the two broken forces divided by the sliding surface is the same, both pointing into the slope. Under the action of prestressing, the anchor rod is actively stressed. It always provides the resistance to the slope in the slope. It will degenerate into soil nails with the loss of prestress and the stop of the deformation of the slope.
Because the understanding of some places is different, if the soil nail of the soil nail wall is named [soil nail", the unit price is very low and low according to the budget, so I and some of my colleagues tend to name it as a non-prestressed soil anchor. . This is also a problem that has to be paid attention to.

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