Reliability Of Anchor Support And Adjustment of Resistance In Construction

Reliability of anchor support and adjustment of resistance in construction

Anchor support utilizes anchors, rods, buttresses and various components or spray layers to give the surrounding rock a certain support strength, forming a support system together with the surrounding rock, and with the deformation of the surrounding rock, the support force increases continuously. Anchor support is essentially the installation of anchors in the surrounding rock of the roadway, so that the layered, soft rock is reinforced in different forms, forming a complete support structure, providing a certain support resistance, and jointly resisting the displacement and deformation of the external surrounding rock.

Anchor support: It plays the role of suspension for unstable rock layer. Due to the action of pre-tensioning force, the formation of compression rock sorghum prevents the delamination of laminated rock body, increases the friction between rock layers, and together with the shear effect of the anchor itself, prevents the relative sliding between rock layers, and enhances the bearing capacity of the rock layer.

Due to the adjustability of the support resistance of the left-rotation non-longitudinal rib anchor, it has a wide adaptability to the rock layer, and can play different roles in different types of surrounding rock conditions.

The actual construction shows that the tensile and shear resistance of the left-handed longitudinal ribless anchor and the extrusion reinforcement after compression can better reinforce the surrounding rock. The pull-out test shows that the initial anchorage force is more than 40 kN/m, which can satisfy the construction in most cases.

The following are several requirements for the use of the environment of the left-handed anchor without longitudinal ribs:

1、Left-rotating no longitudinal rib anchor construction is simple, little interference, conducive to rapid digging, while the adaptability of the rock layer is wide.

2、Left-rotating non-longitudinal rib anchors can not effectively fill the rock cracks like mortar anchors, so from the durability point of view, it is not suitable to be used in rock formations with erosive groundwater action.

3, Guankou power station application practice shows that for small-scale water conservancy projects, left-handed no longitudinal rib anchors are technically and economically feasible.

Working principle and characteristics of right-handed equal strength threaded anchor

The working principle and characteristics of right-handed equal-strength threaded anchor: right-handed equal-strength threaded anchor is a new type of anchor with full-length anchorage and active reinforcement of surrounding rock, and its three-dimensional part is a high-strength steel pipe with longitudinal slits, which, when installed in the drilling holes slightly smaller than the diameter of the pipe, can immediately exert radial pressure on the hole wall in the full-length range and friction to prevent the surrounding rock from sliding down, together with the bearing force of the anchor pallet plate, thus making the surrounding rock in a three-way force state, and realize the rock great. In the case of blasting vibration surrounding rock anchor displacement, etc., the later anchoring force has increased significantly, when the surrounding rock is significantly displaced, the anchor does not lose its support resistance, it has better characteristics than the rising shell type anchor.  

(1) Wooden anchor. There are two kinds of wood anchors used in China, i.e. ordinary wood anchors and compressed wood anchors.

(2) Reinforced or wire rope mortar anchor. Cement paddle is used as the bonding agent between anchor and surrounding rock.

(3) Inverted wedge metal anchor. This type of anchor used to be one of the most widely used forms of anchors. Because it is simple to process, easy to install, and has a certain anchoring force, this kind of anchor rod is still in use to this day within a certain range.

(4) Right-handed equal-strength threaded anchor. It is a kind of full-length friction anchored anchor rod. This kind of anchor has the characteristics of simple installation, reliable anchorage, large initial anchorage force, and long-time anchorage force grows with the movement of surrounding rock.

(5) Resin anchor. Resin is used as the binder of the anchor, and the cost is high.

(6) Fast hard expanding cement anchor. It is made of ordinary silicate cement or slag silicate cement by adding additives, which has the characteristics of quick-setting, early-strength, water-reducing and expansion.

(7)Double-fast cement anchor. It is made of finished early-strength cement and double-fast cement mixed in a certain proportion. It is characterized by fast hardening, fast setting and early strength.