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| EXPERIMENTAL STUDY OF LOAD TRANSFER LAW
OF PRESTRESSED CABLES UNDER LOESS STRATUM |
(1. College of Architecture and Civil Engineering，Xi′an University of Science and Technology，Xi′an，Shaanxi 710054，China；
2. Institute of Drilling Technology，Xi′an Branch of China Coal Research Institute，Xi′an，Shaanxi 710077，China) |
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Abstract Based on the previous theoretical analysis and the systematic analysis of field pull-out test data，the influence of anchorage length，pull-out load as well as cable diameter on the load transfer law of the prestressed cable under the specific condition of loess stratum are analyzed. The analysis results show that：(1) The most rational effective anchorage length of prestressed cable is 6–8 m. The ultimate bearing capacity of the prestressed cable can not fully be exerted when the anchoring segment is too short；and the prestressed cable is easy to be wasted under the condition that the anchoring segment is too long. (2) The axial force of cable continues to transfer the remote anchorage section getting smaller and smaller whose peak value grows and shifts to the remote with the increase of the pull-out load，which is associated with the fact that the axial force of the front anchorage segment produces local plastic damage when the pull-out load exceeds the anchor¢s ultimate tensile strengths. (3) Soil mass and anchoring body have significant heterogeneity and nonlinearity，which results in being of the relatively weak or noncontinuous interfaces between grout and soil. The distribution of the anchorage force on the weak plane discretes jump while the pull-out load increases to a certain level. (4) In engineering practice，the starting points of anchoring force distribution curves do not overlap with the port anchor absolutely but deviate from the relative vertical axis to varying degrees，which makes the actual length of anchor is usually shorter than the theoretical design length. (5) Under the loess stratum，the ultimate capacity of some prestressed cables increases linearly with their diameters increase，independent to the effective anchorage length. The growth factor is about 1.1. These conclusions with some theoretical and practical values provide a reference for the design and construction of anchor support engineering in the loess region.
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Received: 10 June 2010
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2010, Vol. 29 
