Over-consolidation ratio

Yc,max is the single amplitude maximum cyclic shear strain OCR is the over consolidation ratio P = 0.45 (found experimentally)... 

There are countless examples in the literature of oedometer test graphs from whieh pre-consolidation or yield pressures have been determined that are completely absent when the data are re-plotted on linear scales. Examples are given in Figures 4 and 5. Figure 4 shows an example from a residual soil found in the southern part of the USA, known as Piedmont soil. Values of pre-eonsolidation pressure and over-consolidation ratios (OCRs) determined from the log plot are shown in the figure. The data have been re-plotted using a linear seale for pressure these linear plots show no evidenee of yield or pre-eonsolidation pressures. 

From Tirant (1979), K, increases with Over Consolidation Ratio (OCR) or Dj. ... 

If the current stress state of volumetric effective stress is lower than the stress state experienced in the past, the clay is said to be over-consolidated, and we define the over-consolidated ratio as OCR= py p[ where p is the preload pressure and p l... 

Stiffness also depends on the stress history or over-consolidation ratio (OCR). The stiffness of soil at virgin loading is lower than the stiffness at unloading/reloading conditions. 

Let us consider the shearing behavior of a heavily over-consolidated clay. We start to make it swell from a point A on the normally consolidated line (NCL) to a point B shown in Fig. 6.3d, e. When we perform an undrained triaxial test, the shear stress q attains the yield point P on the Hvoslev surface (namely the maximum point for the stress ratio rj = q/p ), and moves on the Hvoslev surface to reach the point C on the CSL. On the other hand, if a drained triaxial test is performed from the point B, the shear stress q attains the peak strength Q, then the stress reaches a residual state R through a softening process. Note that in practical experiments a shearing slip surface is commonly observed, and the whole specimen cannot reach the residual state. 

Tests undertaken by Coop and Airey (2003) indicate that at a same void ratio compacted samples will display more creep than samples of the same carbonate sand that have been over-consolidated. However, as indicated before, surcharging may not always be feasible because of the high loads required to move down the NCL. 

The sensitivity of clays is defined as the ratio of their undisturbed and remoulded strength, and varies from about 1.0 for heavily over-consolidated clays to values... 

Accordingly, a 0-1 molar solution of phthalic anhydride in benzene (100 ml.) was pyrolyzed at 690° under nitrogen at a steady rate of 30 ml/hr (Fields and Meyerson, 1965). The pyrolysis tube was Vycor, filled with Vycor beads contact time was 11 5 sec, which gave a 58% conversion of the phthalic anhydride. Acetylene was steadily evolved, along with carbon dioxide and carbon monoxide in a 1 1 ratio these were identified in the gas stream by mass-spectral analysis of samples taken at regular intervals. The benzene was distilled off and the products boiling over 180° (2 g) were analyzed by mass spectrometry on a Consolidated Model... 

During secondary consolidation, the relationship between the void ratio and the log of time is usually linear line sloping downward over the range of times of interest. There is no... 

Akira et al. examined initial and follow-up CT scans in 40 patients with pulmonary sarcoidosis (95). Predominantly nodular or multiple large nodules disappeared or decreased in size at follow-up. A conglomeration pattern shrank and evolved into bronchial distortion and decline in FEVi/FVC ratio. Interestingly, GGO and consolidation evolved into honeycombing in some patients. Because sarcoidosis has the potential to evolve over time, initial CT features have limited prognostic value (76). However, certain CT features have predictive value. Focal nodules, alveolar opacities, consolidation, or GGO suggest an active inflammatory component that may reverse with therapy (76,85,96). In contrast, distortion of lung parenchyma, coarse or hnear bands, bronchiectasis, cystic radiolucencies, and bullae reflect irreversible fibrosis (78,79,85,96). 

The fiber volrune content calculation of the pultruded product is obtained by a development similar to Eq. (10.32), that is, the total material volume normalizes the reinforcement volume for one pitch length and is adjusted with the fill ratio J p. The fill ratio is the ratio of the area of the braid (Eq. (10.32)) over the die exit area. Note that the angle 0 is the consolidated BY angle. 

As shown in Fig. 16.2, strains e, which correspond directly to the mobilized forces and thus the efficiency of the two layers, are significantly different. For the bottom layer the maximum strain in the reinforcement is 7.5%, whereas for the upper one (0.5 m above) it measures 4.1%. Consequently, the bottom layer tends to be overstressed because of the undastressing (not full mobilization) of the upper one. The corresponding stress ratio which is the mobilized tensile force—UTS is about 60% for the bottom layer (a high value) and about only 30% for the upper layer (Blume et al., 2004). Despite the huge settlement of the embankment, vertical and horizontal deformations in the critical zone adjacent to the railroad remained in the range of some millimeters over the whole construction period and after more than a year of final consolidation, until September 2005. 

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