| Xiaowan Lancang River is located in Yunnan Province, western China. It is at the lower part of Lancang River, near the terraced field. It is the most powerful main hub of both the utilization efficiency of the hydroelectric project in western China. And it is one of the top ten landmark projects. Xiaowan Hydropower Engineering building from the concrete arch dam, spillway works and underground water power plant project consists three parts. There are two diversion tunnel and the other on the earth-rock cofferdam downstream.Xiaowan magnitude of the project, the high technical difficulty, the vast majority of the construction site there are different degrees of slope of the high, wide span, thrust, stress concentration and other factors, to ensure the smooth implementation of the safety and permanent, required prestressed anchor to anchor. Prestressed cable as a permanent means of reinforcement, it is the slope of Little Along the rivers, behind the dam body and the resistance of the retaining dam reinforcement project in one of the main projects. Particularly, it is along the rivers up to700m, engineering geological conditions are complicated, and the two sides are widely distributed accumulation body, unloading fissures, most of the excavation slope stability safety engineering needed to support and ensure the anchor, anchor slope supporting a huge amount of the total to10,192beam design. Prestressed cable as a permanent means of reinforcement, is Little Bay. It goes along the rivers and the whole plant slope slope slope reinforcement works in the main project.Generally speaking, it contains a large number of existing pre-stressed anchor optimization based on the results, the slope of Little Bay anchor station for the study, for each construction time, construction sites and various prestressed cable construction process of the different reinforcement problem, that various forms of prestressed cable structure, tonnage levels of different characteristics of different construction techniques, the main types of prestressed cable, the force characteristics and mechanism were studied analysis. Research ideas in this paper as follows:by assuming certain conditions, to establish a simplified model of slope stability analysis, on the one hand gives way to optimize the parameters of a uniform definition of the other hand, detailed analysis of the relationship between various parameters and design sensitivity and evaluation indicators through the proposed optimization, combined with economic and construction facilities, to further explore the initial optimization principle, in order to optimize the design of prestressed anchor the establishment of a unified theory to provide inspiration. Then optimized by means of some experiments, the optimal design of prestressed cable method is applied to actual engineering Xiaowan go.The use of laboratory simulation experiments and field studies combined production test methods used for the construction of this hydropower station in Anchor. My study was based on the pull decentralized, distributed pressure and tension and compression tests carried out distributed anchor, Little Bay power station meets the different parts of the structure of different strata of the internal structure type of bond adaptability requirements. These studies and tests the following conclusions:Tension within the ordinary type of bond stress test results showed that with increase in load anchor Zhang Rojo, paragraph anchor strand within the stress gradually pass to the deep, the higher the load, the deeper the stress transfer; strand stress increases with the depth of anchoring the rapid decay.Rally dispersed, including the anchoring segment anchor strand scattered arrangement, the anchor is passed to the disperse Zhang Rojo set within the anchoring segment at different depths. It can effectively reduce the slurry at the top of the tensile stress concentration, but the rally dispersed anchor strand anchoring depth of2times the normal pull-type.Distributed anchor tension and compression load of the anchor plate inhomogeneities in the0.89-1.08between the anchor plate strand elongation at almost equal, indicating that the anchor plate by force, and the late anchor load losses small, on its anchor is stable, reliable, and the other, the slurry under pressure strain anchor segment, and tension-type anchor within the anchorage segment compared to the type of anchor has a greater overload power; In addition, in the same hole depth and the same steel the case of wire length, tension and compression and pressure-dispersed composite anchor free length increases, the anchor’s ability to adapt to more rock mass deformation.Test results show that the right bank of the accumulation of C,1465m above the anchor body parts, although parts of the rock within the anchoring segment is relatively broken, but no matter what type of anchor used, it can meet the right bank of the C,1465m above the accumulation body1800KN anchor anchor design parameters required, but the common tension-type structure with anchor type of simple, relatively low cost anchor, tension speed, speed up the anchor to facilitate the construction schedule, may give priority to the ordinary tension-type anchor.Cross dam Xiaowan complex geological conditions, decentralized pull anchor, anchor and composite tensile and compressive stress distributed as a supplement normal tension anchor for the site of anchorage section within the rock mass quality is poor, or composite tension and compression can be used to pressure-dispersed anchor, anchor parameters to meet the design requirements.Within the structure of bond on the form, this test was normal tension-type, pull decentralized, complex, and tensile and compressive stress distributed four forms of testing.Common tension-type anchor anchor for the current widely used form of simple structure, the construction of tension, low cost, all bond forms free section and unbonded form can be used, but pull the stress is concentrated within the anchorage section, internal segment of rock anchor high quality requirements, within the anchorage section for the geological conditions were better in the prestressed rock anchor.Rally dispersed using PE-cover protection anchor unbonded strand, PE strand segment within the anchor sleeve stripping in different locations, will be passed to the disperse Zhang Rojo contained within the anchor segments at different depths, reduce the general tension-type anchor cable within the anchorage section stress concentration, but within the anchoring segment longer.Tension and compression and pressure-dispersed composite anchor structure roughly the same, using the pressure plate and squeeze the head, so that the slurry within the anchorage section under compressive stress. The stress characteristics, the performance of the tension and compression and pressure-dispersed composite anchor and general tension and stress distributed anchor-type anchoring segments within the force are essentially different, because the slurry compressive stress, changes in bond section of the stress conditions, can effectively improve the anchoring effect, and internal quality requirements of the rock anchor segment is relatively low, within the anchorage section adapted to poor parts of the rock anchor construction. But also increase the length and anchoring within the anchoring accessories, and increased cost of anchor. |
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