ケーブルボルトによる地下空洞岩盤の先行補強の施工法および現場における作用効果の評価法の検討 [in Japanese] Installation and Evaluation Methods of Cablebolting for Pre-Reinforcements in Underground Rock Mass [in Japanese]
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In order to develop a better practice for enhancing the cost performance and reducing the risk of construction of underground openings, the authors focus on the cablebolting. A field experiment was conducted during constructing an underground powerhouse to establish a construction practice of cablebolting, involving measuring an effectiveness of preset cablebolts for the rock stability.<BR>The conventional construction procedures and equipments for dowels are found to be applicable to cablebolting. The pre-mixed cement, which is commonly applied for conventional dowels, are also applicable to a grout material for cablebolting by adjusting the water-cement ratio of 40 to 45%, which can be controlled by the flow value of around 180.<BR>Through the back analysis considering the non-uniformity of rock elasticity around the underground powerhouse, it is found that the preset cablebolts alleviate the stress relax in the surrounding rock of the underground powerhouse due to its excavation. Such back analysis is useful during the excavation of an underground powerhouse to measure the effectiveness of preset cablebolts and to manage adequate arrangement of post-set supports such as dowels and pre-stressed anchors.
Shigen-to-Sozai 124(2), 112-119, 2008-02-25
The Mining and Materials Processing Institute of Japan