Consolidated undrained triaxial compression tests were conducted from 1.65 m depth subjected to stress levels of 10.4–40.5 kPa. The results showed that most test data failed to reach the tension cut-off line (q/p′ = 3). For peat, the membrane correction effect on peat shear resistance was strain dependent – generally small within 10% shear strain, but significant above 10% shear strain. A critical state line for peat was determined based on the maximum curvature approach. Of the data recorded for peat, 78% fell within the range 30–60°, increasing to 90.4% when ignoring points lower than 10 kPa. Organic content (OC) also had an effect on the shear behaviour. For OC > 75%, the deviator stress behaved like an organic soil; otherwise, the peat behaved more like a mineral soil. In peat samples with OC > 75%, the direct shear box test gives higher estimates of shear strength than the triaxial shear test, but which are not necessarily accurate – the mechanism of direct shear acts only at the centre of a specimen, while triaxial shear can shear throughout the specimen.

中文翻译：

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不同应力水平下泥炭的剪切行为

在 10.4–40.5 kPa 的应力水平下，从 1.65 m 深度进行固结不排水三轴压缩试验。结果表明，大部分测试数据未能达到张力截止线（q / p′ = 3). 对于泥炭，膜对泥炭抗剪力的修正作用依赖于应变——通常在 10% 剪应变内较小，但在 10% 剪应变以上时显着。基于最大曲率法确定了泥炭的临界状态线。在泥炭记录的数据中，78% 落在 30–60° 范围内，忽略低于 10 kPa 的点时增加到 90.4%。有机物含量 (OC) 也对剪切行为有影响。对于 OC > 75%，偏应力表现得像有机土壤；否则，泥炭表现得更像矿质土壤。在 OC > 75% 的泥炭样品中，直接剪切箱试验比三轴剪切试验给出更高的剪切强度估计，但不一定准确——直接剪切的机制仅作用于样本的中心，