Uniform and weak stability of Bresse system with one infinite memory in the shear angle displacements

In this paper, we consider a one-dimensional linear Bresse system in a bounded open interval with one infinite memory acting only on the shear angle equation. First, we establish the well posedness using the semigroup theory. Then, we prove two general (uniform and weak) decay estimates depending on the speeds of wave propagations and the arbitrary growth at infinity of the relaxation function.

Stability performance of demolition waste composite as landfill liner

Landfill liner is one of the essential components that prevent leachate infiltration of the soil from causing pollution. A liner has specific design criteria to function optimally. This study analyses the permeability and stability value of the mixture of composite materials consisting of demolition waste, bentonite, and lime materials. This study using some methods include falling head method for permeability test and direct shear strength for stability test. Based on the results of this research, it can be seen that the mixture of demolition waste and bentonite to composite can reduce the internal shear angle and increase the cohesion. While lime provides a fluctuating value for cohesiveness, it can increase the internal shear angle. The best mixture to be used as an alternative composite liner is the V6 composite which has a demolition waste composition of 79%, 20% bentonite, and 1% lime with a permeability coefficient value of 8.526 × 10−7 cm/s.

Multiparametric Analysis of a Gravity Retaining Wall

The design of a gravity retaining wall should be simple to construct, quick to build and the best economic solution to a problem. This can be achieved by using advanced optimization methods. Since geotechnical engineers are not always able to determine the exact soil properties and other project data, an optimal design of a gravity retaining wall should also be determined for a wide range of input parameters. Therefore, a multiparametric analysis of an optimal designed gravity retaining wall was carried out. Optimum designs of gravity retaining walls were obtained for 567 combinations of different design parameters. Diagrams were developed to help engineers determine the optimum section of the wall, based on construction costs. An exhaustive search was carried out within the available parameters (project data). The parameters were ranked according to which had the most influence on the optimum cost of the gravity retaining wall and the utilization of multiple constraints. The most important parameter for the optimal cost of a gravity retaining wall is the height of the retained ground, followed by the shear angle of the soil, the soil–wall interaction coefficient, the slope angle and the variable surcharge load. The shear angle of the soil is most relevant to the bearing capacity and eccentricity condition, while the soil–wall interaction coefficient is most relevant to the sliding condition. Since European countries apply different load, material and resistance safety factors, the optimization model was developed in a general form, where different design approaches and unit prices could be applied. The case study provides an improved optimization model for selecting the optimal design of gravity walls, for engineers.

Comparison of fly ash with Lapindo mud as a land stabilizer for landfill in Pasuruan–Indonesia

The paper discusses the comparison of fly ash with Lapindo mud as a land stabilizer for a landfill in Pasuruan, Indonesia. Land for landfills has a low level of stability due to the condition of garbage that has accumulated and undergoes a process of decay. This land condition is less favorable to support the construction of the building above it if one day the location is used for construction. Therefore, it is necessary to stabilize the soil first. The purpose of this study was to determine the effect of adding a mixture of TPA soil with fly ash and Lapindo mud. The method used by sieve testing and compaction of the specimens for each treatment consisted of a mixture of TPA soil with fly ash and TPA soil with Lapindo mud, while the percentages of fly ash and Lapindo mud to the dry weight of the original soil were respectively 0 %, 10 %, 15 %, and 20 %. The results showed that stabilization of the landfill with fly ash reduced the silt content while stabilization with Lapindo mud increased the levels of silt in the landfill so that fly ash was better than Lapindo mud for stabilization of the landfill. The specific gravity values for both stabilization mixtures increased equally. Based on the results of the standard compaction test for the addition of a mixture of fly ash, the OMC value decreases and the greater the value of dmaxs indicates that fly ash is good for landfill stabilization, while the addition of a mixture of Lapindo mud increases the OMC the smaller the value of dmaxs. For the direct shear test of the two mixed soils, the value of the internal friction angle (Æ) increased. The percentage value of the optimum mixture of mixed soil+fly ash is 14 % with an internal shear angle (Æ) of 38°, while the stabilization of landfill with Lapindo mud obtained the optimum mixture percentage value of 11 % with an internal shear angle (Æ) of 31°

The role of shear deformation in pure tungsten: Mechanical properties and micro-mechanism

The effects of shear deformation at 1173 K on the mechanical properties and deformation mechanism of pure tungsten are investigated by molecular dynamics (MD). The results show that the shear deformation of pure tungsten is dominated by dislocation multiplication and slip band deformation. The shear angle has a significant effect on the mechanical properties of pure tungsten. The yield strength is 4.21 Gpa at a shear angle of 11[Formula: see text], and it increases significantly to 11.84 Gpa while the shear angle increasing to 27[Formula: see text]. In the plastic deformation stage, the stress–strain curve shows obvious oscillation due to the interaction of dislocations in the single-crystal tungsten and the effect of strain strengthening. In addition, the evolution of dislocation and twining in the compression system against shear angle indicates the variation of deformation behavior. When the shear angle is 11[Formula: see text], the lengths of dislocation 1/2[Formula: see text] and [Formula: see text] increase to a peak rapidly, which illustrates dislocation strengthening. However, when the shear angle is more than 11[Formula: see text], the decrease of dislocation length and the appearance of twins along [Formula: see text] direction demonstrate the twining accompanied with dislocation tangling, resulting in the additional increase of strength.

Analysis Of The Residual Red Soil Shear Test With The Slurry Method In The Regency Of Semarang

Residual soil is found in most areas with mountainous, hilly, and undulating topography. This soil is marked by red or brown color. This study aims to determine the physical and mechanical properties of soil in the original soil and residual soil conditions using the slurry method. Research objects were taken from residual red soil of The East Ungaran District, Bergas District, and Bawen District. Analysis of the physical and mechanical properties test shows that the soil sample is a type of clay with kaolinite constituent minerals and moderate swelling ability, and direct shear testing from locations L1, L2, and L3 obtained residual peak shear angles using the slurry method of 29,249 °; 31,341 °; 31,964 ° and constant residual shear angle value of 8,082 °; 8,138 °; 7,294 °, the value of the original soil shear angle has a value of 32.82 °; 31.44 °; 31.98. The higher the value of the plasticity index, the higher the value of the free swell. The relationship between the plasticity index and the value of the residual peak shear angle shows that the results of the peak shear angle and the plasticity index are still within the scope of standard deviation. The value of the constant residual shear angle with the slurry method is much smaller than the test result graph.

A New Result of Stability for Thermoelastic-Bresse System of Second Sound Related with Forcing, Delay, and Past History Terms

We consider a one-dimensional linear thermoelastic Bresse system with delay term, forcing, and infinity history acting on the shear angle displacement. Under an appropriate assumption between the weight of the delay and the weight of the damping, we prove the well-posedness of the problem using the semigroup method, where an asymptotic stability result of global solution is obtained.