Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Filtration of Broadly Graded Cohesive Dispersive Base Soils
AbstractDispersive soils are highly susceptible to erosion, particularly when they are used as a base soil for the core of an earth dam. To prevent migration of the core material, the required filter must be designed and properly positioned in the structure. A study was carried out to assess the adequacy of the existing filter design criteria in controlling core materials that are not only dispersive but also broadly graded and are commonly available for use in the construction industry. The criteria of D15f/d85≤5.5 and D15f≤0.28 mm, each with a reasonable factor of safety, were found to be applicable for the broadly graded, highly dispersive soils from Group 1 and Group 2, respectively. The criteria of D15f/d85reduced≤9 for the soils of Group 1, D15f/d85reduced≤7 for the soils of Group 2 with significant clay content, and D15f/d85reduced≤2 for the soils of Group 2 with significant silt content were also found to be acceptable. Thus, the required D15f size of a filter reduces with the increasing dispersivity of the corresponding base soil. The dispersivity prevalent in the base soils requires the required no-erosion filter boundaries for the soils of Group 2 to be lowered—more so than for the soils of Group 1. Furthermore, the constriction-based criterion of Dc35/d85*≤1.25 was found to be acceptable for the base soils of Group 1 with high dispersivity, with the corresponding filter having a relative density of 75%. However, for the base soils of Group 2, the criterion of Dc35/d85*≤1.0 was found to be acceptable; for the highly dispersive type, the required criterion was Dc35/d85*≤0.5. Further tests were carried out by simultaneously considering the effects of the changing particle size distribution (PSD) and the percent dispersion (D) of the base material on the required no-erosion filter boundary, resulting in the new criterion of D15f/d85=10.0exp(−0.009D) for the soils of Group 1. However, for the soils of Group 2, the effect of changing the d85 on the required no-erosion filter boundary was not as profound as the effect of changing dispersivity, resulting in different no-erosion filter boundaries for the various ranges of dispersion.
Filtration of Broadly Graded Cohesive Dispersive Base Soils
AbstractDispersive soils are highly susceptible to erosion, particularly when they are used as a base soil for the core of an earth dam. To prevent migration of the core material, the required filter must be designed and properly positioned in the structure. A study was carried out to assess the adequacy of the existing filter design criteria in controlling core materials that are not only dispersive but also broadly graded and are commonly available for use in the construction industry. The criteria of D15f/d85≤5.5 and D15f≤0.28 mm, each with a reasonable factor of safety, were found to be applicable for the broadly graded, highly dispersive soils from Group 1 and Group 2, respectively. The criteria of D15f/d85reduced≤9 for the soils of Group 1, D15f/d85reduced≤7 for the soils of Group 2 with significant clay content, and D15f/d85reduced≤2 for the soils of Group 2 with significant silt content were also found to be acceptable. Thus, the required D15f size of a filter reduces with the increasing dispersivity of the corresponding base soil. The dispersivity prevalent in the base soils requires the required no-erosion filter boundaries for the soils of Group 2 to be lowered—more so than for the soils of Group 1. Furthermore, the constriction-based criterion of Dc35/d85*≤1.25 was found to be acceptable for the base soils of Group 1 with high dispersivity, with the corresponding filter having a relative density of 75%. However, for the base soils of Group 2, the criterion of Dc35/d85*≤1.0 was found to be acceptable; for the highly dispersive type, the required criterion was Dc35/d85*≤0.5. Further tests were carried out by simultaneously considering the effects of the changing particle size distribution (PSD) and the percent dispersion (D) of the base material on the required no-erosion filter boundary, resulting in the new criterion of D15f/d85=10.0exp(−0.009D) for the soils of Group 1. However, for the soils of Group 2, the effect of changing the d85 on the required no-erosion filter boundary was not as profound as the effect of changing dispersivity, resulting in different no-erosion filter boundaries for the various ranges of dispersion.
Filtration of Broadly Graded Cohesive Dispersive Base Soils
Vakili, Amir Hossein (Autor:in) / Bin Selamat, Mohamad Razip / Abdul Aziz, Hamidi Bin
2015
Aufsatz (Zeitschrift)
Englisch
BKL:
56.20
Ingenieurgeologie, Bodenmechanik
Filtration of Broadly Graded Cohesive Dispersive Base Soils
| British Library Online Contents | 2015