Internally unstable soils can pose severe conditions to granular and geotextile filters in geotechnical engineering works. Regarding the latter, several researchers have investigated the behaviour of such filters in contact with internally unstable soils and severe clogging and flow rate reductions of soil-geotextile filter systems have been observed in several cases. This paper presents a study on the prediction of boundary values for hydraulic properties of nonwoven geotextile filters in cohesionless internally unstable soils. A broad survey on results of filtration tests present in the literature was carried out for the development of a database for the study. The results obtained show that significant reductions in soil-geotextile system permeability coefficient and flow rate may occur independent on the type of test carried out, quite often as a consequence of poor hydraulic behaviour of the soil rather than geotextile filter clogging. The study has identified the level of importance of relevant parameters to assess potential malfunction of the soil-geotextile system and equations were developed to predict lower bound values and estimates of soil-geotextile system permeability coefficient for preliminary analyses.

中文翻译：

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内部不稳定土壤非织造土工布系统的水力特性研究：边界值和初步估计


内部不稳定的土壤会对岩土工程中的颗粒和土工布过滤器造成严重影响。关于后者，一些研究人员调查了这种过滤器与内部不稳定土壤接触的行为，并且在几种情况下观察到土壤土工布过滤系统的严重堵塞和流速降低。本文介绍了无粘性内部不稳定土壤中无纺布土工布过滤器水力特性边界值预测的研究。对文献中存在的过滤测试结果进行了广泛的调查，以开发该研究的数据库。获得的结果表明，土壤土工布系统的渗透系数和流速的显著降低可能与所进行的测试类型无关，这通常是由于土壤的不良水力行为而不是土工布过滤器堵塞的结果。该研究确定了相关参数对评估土壤-土工布系统潜在故障的重要性水平，并开发了方程式来预测土壤-土工布系统渗透系数的下限值和估计值，以进行初步分析。