JOURNAL OF YANGTZE RIVER SCIENTIFIC RESEARCH INSTI ›› 2020, Vol. 37 ›› Issue (10): 117-124.DOI: 10.11988/ckyyb.2019077224

• ROCK-SOIL ENGINEERING • Previous Articles     Next Articles

Experimental Study on Group Anchor Effect in Strongly Unloading Rock Mass of a High and Steep Slope

SONG Cui-rong1, LI Zheng-bing1,2, ZHANG Yin2   

  1. 1. Power China Sino-hydro Bureau 7th Co., Ltd., Chengdu 611130, China;
    2. College of Environment and Civil Engineering, Chengdu University of Technology, Chengdu 610059, China
  • Received:2019-07-04 Revised:2019-08-14 Online:2020-10-01 Published:2020-10-29

Abstract: Pressure-distributed unbonded prestressing anchor cable is the major support for the strongly unloading rock mass in the left-bank high and steep slope of Jinping Hydropower Station. Large anchoring force and small spacing of the anchorage gave rise to notable compressional deformation of the rock mass; the mutual influence of anchor cables led to massive prestress loss. A physical model test on the anchoring of unloading rock mass was carried out to examine the displacement and deformation of rock mass as well as the superposition of anchoring force and prestress loss in association with Mindlin’s solution. The anchor group effect mainly includes 1) the compression of unloading rock mass posed by stress superposition; 2) the prestress loss of anchor cable caused by tensions on adjacent ones. Furthermore, the calculation methods of rock mass displacement and prestress loss rate were obtained via experimental analysis and theoretical derivation. Reasonable spacing of anchor cables and appropriate increase of anchor cable length can effectively reduce the prestress loss caused by group anchor effect.

Key words: high and steep slope, unloading rock mass, pre-stressed anchor cable, group anchor effect, physical model test

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