Topic
Quick condition
About: Quick condition is a research topic. Over the lifetime, 17 publications have been published within this topic receiving 370 citations.
Papers
TL;DR: In this article, the effect of upward bed seepage on the critical condition of sediment motion in open channel flow was investigated both analytically and experimentally by analyzing the forces acting on a sediment particle lying on a permeable horizontal bed subject to seepages.
Abstract: This study investigates the effect of upward bed seepage on the critical condition of incipient sediment motion in open channel flow both analytically and experimentally. The critical condition was derived by analyzing the forces acting on a sediment particle lying on a permeable horizontal bed subject to seepage. The ratio of the critical shear velocity with seepage to that without seepage depends on the ratio of theJiydraulic gradient of seepage to its critical value under the quick condition. Experimental results concerning incipient motion of cohesionless uniform sediments in open channel flow show that for a particular size of sediment, the critical shear velocity decreases with increasing seepage velocity. All measurements generally support the theoretically derived expression of the critical shear velocity in the presence of an upward seepage.
113 citations
TL;DR: In this paper, the results of research carried out during the past fifteen years on the quick clays of eastern Canada are described, and the important influence of rate of loading has revealed the need of careful interpretation of laboratory tests for field application.
79 citations
TL;DR: In this paper, the authors present theoretical analyses and experimental results of seepage effects on sediment entrainment and the critical shear stresses with different suction rates were calculated using the experimental results.
Abstract: This paper presents theoretical analyses and experimental results of seepage effects, especially downward seepage, on the initiation of cohesionless sediment particles. The theoretical analysis examines how the additional seepage force acts to modify the critical shear stress for sediment entrainment. Laboratory experiments were conducted using medium sand with diameter of 0.9 mm with downward seepage to quantitatively show suction effects on sediment entrainment. The critical shear stresses with different suction rates were calculated using the experimental results. The measured data together with published results provide an overall view on seepage effects on the initiation of cohesionless sediment transport. Depending on whether seepage is in the form of injection or suction, it will either increase or decrease the critical shear stress. The result reveals that the ratio of drag force at the threshold condition with seepage to that without seepage is dependent on the ratio of the hydraulic gradient with seepage to its value at the quick condition.
51 citations
TL;DR: In this paper, the authors show that there are eight different mechanisms that may lead to the development of sensitivity in a given unmodified and stripped-branched clay, i.e., using salt water from marine clays and separating chemical compounds from the clays.
Abstract: FACTORS WERE EXAMINED LEADING TO DIFFERENCES BETWEEN UNDISTURBED AND REMOLDED CLAY FABRICS AND INTERPARTICLE FORCES. A CONSIDERATION OF AVAILABLE KNOWLEDGE WOULD SUGGEST THAT THERE ARE EIGHT DIFFERENT MECHANISMS WHICH MAY LEAD TO DEVELOPMENT OF SENSITIVITY. OF THOSE INDICATED ONLY TWO - LEACHING OF SALT WATER FROM MARINE CLAYS AND THE INTRODUCTION OF DISPERSING CHEMICALS, EITHER THROUGH DECOMPOSITION OF MATERIAL ALREADY PRESENT OR BY LEACHING INTO THE CLAY - WOULD APPEAR ADEQUATE TO ACCOUNT FOR EXTRA QUICK CLAYS. ION EXCHANGE EFFECTS, PARTICLE ARRAINGEMENTS INDUCED BY PHYSICAL FACTORS ONLY, AND CEMENTATION MAY LEAD TO SLIGHTLY QUICK CLAYS, BUT THE MORE USUAL CONTRIBUTION IS PROBABLY MUCH SMALLER. THE REMAINDER - SILT SKELETON-BOND CLAY STRUCTURE, THIXOTROPIC HARDENING, AND WEATHERING - APPEAR ABLE TO ACCOUNT FOR ONLY MEDIUM SENSITIVITIES. THE TOTAL SENSITIVITY OF A GIVEN UNDISTRUBED CLAY MAY BE MADE UP OF CONTRIBUTIONS FROM SEVERAL CAUSES. /ASCE/
44 citations
1 Jan 1972
TL;DR: In this article, a method of measuring the LATERAL EARTH PRESSURE at rest (K SUB 0 value) was proposed to measure the stress of a vehicle's wheel in the soil around a piezometer tip.
Abstract: THIS PAPER DEALS WITH A SIMPLE METHOD OF IN-SITU MEASUREMENT OF THE LATERAL EARTH PRESSURE IN NORMALLY CONSOLIDATED CLAYS. THE METHOD DEVELOPED IS BASED ON THE PRINCIPALS OF HYDRAULIC FRACTURING. A VERTICLE CRACK IS INITIATED IN THE SOIL AROUND A PIEZOMETER TIP. THE WATER PRESSURE AT WHICH THE CRACK CLOSES IS MEASURED, AND THIS PRESSURE IS BELIEVED TO BE IDENTICAL TO THE TOTAL STRESS ACROSS THE CRACK. FROM THIS THE COEFFICIENT OF EARTH PRESSURE AT REST (K SUB 0 VALUE) CAN BE CALCULATED. THE METHOD IS USED K SUB 0 VALUES AT SIX SITES. AT TWO OF THESE THE CLAY IS QUICK, AND AT THE OTHER FOUR NON-QUICK LEAN OR PLASTIC. THE K SUB 0 VALUES ARE FOUND TO BE IN THE RANGE 0.40-0.50 FOR THE QUICK AND 0.50-0.60 FOR THE NON-QUICK CLAYS. BENEATH A FILL AN INCREASE IN THE HORIZONTAL STRESSES IS MEASURED. A COMPARISON OF THE K SUB 0 VALUES OBSERVED IN THE FIELD WITH THOSE MEASURED IN THE LABORATORY INDICATES THAT IN A CLAY DEPOSIT K SUB 0 INCREASES WITH TIME. /AUTHOR/
33 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2012 | 1 |
| 2009 | 1 |
| 2007 | 1 |
| 1999 | 1 |
| 1982 | 1 |
| 1977 | 1 |