Failure zone

An example of the effects of waste settlement can be illustrated by a recent incident at a hazardous waste landfill facility in California.5 At this facility, waste settlement led to sliding of the waste, causing the standpipes (used to monitor secondary leachate collection sumps) to move 60-90 ft downslope in 1 day. Because there was a very low coefficient of friction between the primary liner and the geonet, the waste (which was deposited in a canyon) slid down the canyon. There was also a failure zone between the secondary liner and the clay. A two-dimensional slope stability analysis at the site indicated a factor of safety (FS) greater than 1. A three-dimensional slope stability analysis, however, showed that the safety factor had dropped below one. Three-dimensional slope stability analyses should therefore be considered with canyon and trench landfills. 

A series of possible outcomes from a comparison of the two methods is shown in Figure 9.5. In this case, the shaded area is not an equivalence zone as this is no longer relevant. What is now shown is the failure zone . Differences in this zone would be indicative of a rise in urea concentrations too great to be acceptable. 

In the current case, we calculate the upper confidence limit as this indicates the worst credible interpretation of the data. Then, the condition for acceptance of the new treatment is that this upper limit does not enter the failure zone starting at +1 mM. As the decision is based solely on this upper limit, a lower limit would have served no useful purpose and was not calculated. 

References 46 and 47. These approaches have been based on models of cracks in viscoelastic materials in which finite crack tip stresses are obtained by considering a small failure zone or damage region to exist ahead of the crack, somewhat analogous to the Dugdale model... 

Typical inflated cord tension plots for a truck tire are shown in Figure 14.13. In an unloaded state the cord tension for the belts tends to be at the tire centerline, and the ply tension is greatest at the point corresponding to the sidewall location however, on application of a load to the inflated tire and consequent deflection, the cord tensions increase at the belt edges away from the centerline and in the bead zone. As reviewed earlier, these two regions tend to be the failure zones in a tire construction (Figure 14.14). 

Figure 8 is the failure field distribution diagram of barrier pillar. It is observed from the figure, influenced by disturbance of chamber mining, part of barrier pillars turns into plastic state, the failure zone is not cut through and the failure is shear combined failure along strike of ore deposit. 

The failure surface has been basically formed in past peak stage of axial stress, plastic zones of internal sample mainly focus on secondary failure surface. In past-peak 95%, shown in Fig. 5(c), the main failure surface of upper of specimen connects with secondary failure surface, failure surfaces of upper and bottom that connected with outer wall dmost connect. In past-peak 90%, shown in Fig. 5(d, e), due to failure surfaces connecting from upper of specimen to bottom, strength of specimen reduce. Compression is the main cause of failure surface, and failure zones of tension or shear mainly focus on the connected surface, the rest is rarely. In residue level, shown in Fig. 5(f), the change of tensile or shear is not very obvious. 

The failure zones caused by compression have a gradually connecting trend during process of unloading tests, cracks caused by compression are in the majority of cracks. The trend of concentration of shear failure is the direction that failure surfaces develop in. 

Generally saturated sand with gravel to fine sand and silty sand. SPTblow count usually less than 10 in failure zone Saturated loose (N 5) medium sands to silty sands (Dg) 0.25 to 0.40) with less than 10% fines... 

Preliminary testing was conducted at room temperature in air and at 77 K with liquid nitrogen surrounding the specimens. At least three specimens were tested at each temperature. Specimens were first cycled once or twice to approximately 50% ultimate load to check the seating of the specimen and to measure the elastic modulus. The ultimate compressive failure zones were generally near one end or the other, but outside the end caps. Failure of the specimens was due to delamination. 

Beyond the shear failure zones, there are tensile failure zones caused by tensile stresses, which can be generally grouped into two distinct types, circumferential tensile failure zones and radial crack zones. 

Following the crashed zone, circumferential tensile failure zones with gray color in Figure 2 occur. This failure zones consist ofjustone surface of a crack. This crack could occur in any axial cross section planes around the tunnel axis and it is caused by the circumferential stress. Figure 4 shows the curves of dynamic stresses (a, a, ... 

B/C cohesive or interfacial failure along the glueline (B), with or without a fine layer of fibres visible in the failure zone. The extent of fibres (C) visible within the failure area of type B must be given in % rounded to the nearest 10%. 

CP-14 Contaminatlo n Event (Rooms 107, 110, 111, 112)-SCB manipulator boot/ penetration confinement failure (Zone D- SCB manipulator boot/ penetration fatigue/failure operator error external forces applied to SCBs (natural phenomena/ external event) Mechanical properties of boot penetration ventilation (AP) control prevents leaks by inward flow operator procedure, training II Audible SCB (AP) monitor Ventilation flow (AP) shielding Procedure, training -Workers D -Collocated workers D -Public D -Environment D 3 3 3 3 manipulator boot/ penetration integrity -Regular boot replacement for manipulator maintenance... 

Figure 9. Plastic failure zone under the limit pressure P=170 kPa.

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