| Compression rock anchor is a relatively new type of geotechnical anchoring technology, and it is quickly and widely applied to the water conservancy slope anchorage, roads cutting support, tunnel portal reinforcement,foundation anti-floating in the past ten years in China. It shows excellent behavior and better cost performance in project. However, the engineering application is far ahead of theoretical research of compression rock anchor. Therefore the phenomena of potential risks or excessive waste may exist in engineering practice. This dissertation is based on the national science fund for distinguished young scholars"Disaster Reduction for Geotechnical Engineering"(No.50625824) and programs for science and technology development of Chongqing science and technology committee (CSTC2008AC0077). A systemic study on anchorage behavior and load transfer mechanism of compression rock anchor is executed through field investigation, material collection, theoretical analysis, experimental research and numerical simulation method. The main work is summarized as follows:①According to the main failure pattern of compression rock anchor, the theoretical of load-transfer mechanism is studied. The equations that describe grout- rock interface interactional law is established based on the Kelvin's solution by selecting the appropriate load-transfer model and considering the three-dimensional stress state of grout. The grout-rock interface shear stress distribution and axial and radial stress distribution in grout are obtained by solving the equations. Stress field in the surrounding rock mass is analyzed through simplified elastic superimposed model. Parameters of various grouts and rocks are used to analyze the influence on stresses distribution.②The common sedimentary rock, grouting body, high-strength steel in Chongqing are adopted in the laboratory as raw material for the scale model test. After detailing bearing plates and unbounded reinforcing bar for model test,behavior of compression type rock bolts is studied by the test rock bolts with various fixed anchor lengths. The full load—displacement curves are obtained in laboratory. The different behavior of two type bolts is analyzed through comparing compression rock bolts and common tension rock bolts in the same conditions.③Behavior of compression type rock anchor cable is studied by on-situ pulling test on a typical slope. Experimental anchor cables which have a hole of 130mm Diameter, 6 standard steel strands and grout with 30MPa compression capacity are frequently used in rock anchorage engineering. Pulling mechanical behavior of compression rock cables with various failure pattern is obtained. Anchor cables that have various bonded transmission length are poured to find loading-displacement relations. Strain sensors which are fixed on wooden holder are put into cement paste to test the strain and stress distribution curve of fixed anchor length, then on-situ data is compared with theoretical results and model test data. Ductility and residual strength of anchor cables are also studied.④The numerical simulation analysis with actual three-dimensional models and parameters is executed for compression rock anchors and compression load dispersive anchor. The influence on anchorage behavior is analyzed under various conditions that include different fixed anchor lengths and different borehole diameters. Stress field in surrounding rock mass are analyzed by comparing numerical calculation results and test data.⑤The design methods and construction key points of compression rock anchors and compression load dispersive anchors are studied through combining with engineering practice. Optimized design method is advanced in this chapter. This method can reflect how the fixed anchor length influences grout-rock interface maximal shear stress. The increase of bearing capacity in the rock anchor gradually slows down when fixed anchor length is increased. Pretesting loss is measured in situ, the magnitude and reason of the loss is analyzed. Optimized design method is advanced for compression load dispersive anchor and corresponding numerical simulation analysis is done.Through all above studies, the elastic stage test results can be explained by the theoretical research results. Numerical simulation results and the test results are basically obtained the same laws. The three methods are mutually verified. In summary, the theoretical study of this dissertation is reasonable and credible, the test results are accurate and reliable, numerical models are scientific and rational. This study could provide the reference for optimal designs, constructions and relative code revisions of the compression rock anchor.
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