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.

百河滩超高拱坝是在复杂的地质条件下建造的，包括大型柱状节理玄武岩（CJB），节理间距很近，坝基下部有多层夹层和层间剪切带，这可能增加渗水的风险。在相邻的坝基中。因此，采用帷幕灌浆来降低坝基的渗透性。进行了Lugeon和灌浆现场测试以及地质勘探，以研究大坝基础的帷幕灌浆特性。研究结果如下：（1）第一类CJB和角砾岩熔岩在未卸荷情况下的渗透系数为2×10 ^-5〜5  ×10 ^-5  cm / s；第二种类型的CJB的不卸荷值为2.5×10 ^-5〜5  ×10^-5 厘米/秒；而第三类大块玄武岩的卸载量为1×10 ^-5〜3  ×10 ^-5 厘米/秒 （2）岩心表明，泥浆引起岩体反复裂开并扩大了岩体的裂缝，从而导致了岩体的塑性变形。五点Lugeon测试的P〜Q曲线显示曲线形状呈湍流状态，最大Lugeon值出现在最高压力下。（3）经常观察到低渗透条件下灌浆量大的现象。透水率小于1 LU和灌浆的孔段所占比例大于50 kg / m，范围为12.5％至37.5％。渗透率大于10 Lu且灌浆量大于50 kg / m的孔的比例为0至12.5％。该案例研究的结果可为工程建设提供参考。