Strength Model of Backfill-Rock Irregular Interface Based on Fractal Theory

In the two-step open stope subsequent filling mining method, the determination of the strength model for the backfill-rock interface is of great engineering significance to study the stress distribution and stability of the backfill in the stope. Considering the deformation mechanism of the interface and the interaction of the asperities, a strength model for backfill-rock with irregular interface has been proposed based on fractal theory, which can effectively describe the shear mechanical behavior of interfaces with random roughness. The model has been compared with the two-body mechanistic model and good agreements have been achieved. The results show that the shear strength of the interface changes non-linearly with increasing fractal dimension D, when the fractal dimension D is in the range of 1∼1.12. The complete relationship between the interface shear strength and the fractal dimension is given, as the fractal dimension increases from 1 to 2 based on the presented model. At the same time, the quantitative relationship between the interface and backfill friction angles during direct shear testing is analyzed.

Pengaruh Penambahan Batu Kapur Terhadap Kuat Geser Dan Daya Dukung Tanah Lempung

Generally most of Tewang Rangkang area, Tewang Sangalang Garing District, Katingan Regency of Central Kalimantan Province is covered by clay soil with considerable development (high plasticity), the volume will change (expand) when the water content increases (changes). The volume will increase in wet conditions and will shrink when in dry conditions. It is this trait that causes damage to the construction of buildings. The purpose of this study is to know the addition of limestone to the strong value of shear and the carrying capacity of clay soil. This test was done by mixing limestone with soil in a mixture variation of 0%, 5%, 7.5%, 10%, 12.5%. Based on the results of direct shear testing against the strong value of shear and carrying capacity in the original soil obtained a strong value of shear (τ) = 0.184 kg / cm2, qult = 3.36 kg / cm2, after the addition of limestone 12.5% curing 7 days obtained strong shear value (τ) = 0.219 kg / cm2, qult = 26.04 kg / cm2, so that with the addition of limestone gives an influence on the increase in the strong value of shear and the carrying capacity of clay soil.

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.