Curtain grouting experiment in a dam foundation: case study with the main focus on the Lugeon and grout take tests
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ORIGINAL PAPER
Curtain grouting experiment in a dam foundation: case study with the main focus on the Lugeon and grout take tests Jinxi Dou 1,2,4 & Guijin Zhang 1,2 & Mengxia Zhou 3 & Zhilin Wang 3 & Ngawang Gyatso 3 & Mingqiang Jiang 4 & Pooya Safari 5 & Jinquan Liu 5,6 Received: 1 February 2020 / Accepted: 26 May 2020 # Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract The Baihetan super-high arch dam is constructed under complicated geological conditions, including large-scale columnar jointed basalt (CJB) with closely spaced joints and multiple interlayer and intralayer shear belts at the lower part of dam base, which may increase a risk of seepage in adjacent dam foundations. Therefore, curtain grouting is used to reduce the permeability of dam foundations. Lugeon and grouting field tests and geological exploration were carried out to investigate curtain grouting characteristics of the dam foundation. The findings were as follows: (1) the permeability coefficient of the first type of CJB and breccia lava without unloading is 2 × 10−5 ~ 5 × 10−5 cm/s; that of the second type of CJB without unloading is 2.5 × 10−5 ~ 5 × 10−5 cm/s; and that of the unloaded third type of massive basalt is 1 × 10−5 ~ 3 × 10−5 cm/s. (2) The rock core shows that the slurry caused repeated splitting of the rock mass and widened the cracks of the rock mass, which resulted in plastic deformation of the rock mass. The P ~ Q curve of the five-point Lugeon test shows that the curve shape is turbulent and that the maximum Lugeon value appears at the highest pressure. (3) The phenomenon of low-permeability conditions with a large grout take can be frequently observed. The proportion of the hole stages with a water permeability less than 1 LU and grout take greater than 50 kg/m ranges from 12.5 to 37.5%. The proportion of holes with permeability greater than 10 Lu and grout take greater than 50 kg/m is 0 to 12.5%. The findings from this case study can provide a reference for engineering construction. Keywords Curtain grouting . Case study . Grout take . Lugeon values . Columnar joints
Introduction The quality of foundation and abutment rock masses is of great significance for the overall stability and seepage prevention of superarch dams (Zhang et al. 2013; Shi et al. 2018;
* Jinquan Liu [email protected] 1
School of Hydraulic Engineering, Changsha University of Science & Technology, Changsha 410114, Hunan, China
2
Key Laboratory of Water-Sediment Sciences and Water Disaster Prevention of Hunan Province, Changsha 410114, Hunan, China
3
China Three Gorges Projects Development Co., Ltd, Chengdu 610000, Sichuan, China
4
Sinohydro Bureau 8 Co., Ltd, Changsha 410114, Hunan, China
5
Quanzhou Institute of Equipment Manufacturing, Haixi Institutes, Chinese Academy of Sciences, Quanzhou 362000, Fujian, China
6
University of Macau, Macau 999078, China
Shen et al. 2017; Lin et al. 2018; Jin et al. 2018; Fan et al. 2015; Sigtryggsdottir and Snbjornsson 2019; Tang et al. 2019). The Baihetan hydropower station, located
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