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Clay soil is a type of soil that has the characteristics of large shrinkage, this makes clay an unfavorable material in a construction work. Low bearing capacity can lead to instability of a building foundation erected on clay soil and the swelling and shrinkage properties of clay can cause cracks in highway pavements, also rupture or breakage on the ground floor of the dam. In the construction of civil buildings, the cohesion and shear strength of the subgrade have an effect on the planning of a building, so soil stabilization can be carried out before the soil is used. One of the efforts to improve soil stabilization is mixing soil with certain materials in order to improve the technical properties of the soil to meet certain requirements by increasing soil parameters such as density, cohesion, and shear strength. The soil stabilization process includes mixing with gypsum material (CaSO4) to obtain the desired gradation so that the soil properties become better with calcium levels that bind organic matter to clay and also absorb more water which is very useful for strengthening soil. The research was conducted by testing the direct shear strength of the soil (Direct Shear Test) by adding different percentages of Gypsum (CaSO4) ranging from 5% - 10%. The effect of the addition of gypsum on the cohesion value and the optimum internal friction angle occurred in the addition of 7% lime with a value of 0.018 MPa and 24.93o. [ABSTRACT FROM AUTHOR]

Rocks and minerals that exist on earth have electrical properties such as: natural electric potential, electrical conductivity, and dielectric constant. There are various methods used to determine the conditions below the ground surface. One of them is the geoelectric method. This method can be used as a way to investigate the electrical properties of the earth through the response captured from the ground in the form of potential difference, electric current, and electromagnetic field. The resistivity or resistivity geoelectric method is one type of geoelectrical method used to study subsurface conditions by studying the nature of electric currents in subsurface rocks of the earth. Based on the research objectives, the resistivity method is divided into two, namely mapping and sounding. The resistivity method by mapping uses the Wenner configuration, while the resistivity method by sounding uses the Schulmberger configuration. Geoelectric resistivity mapping method is a resistivity method that aims to study the horizontal variation of the resistivity of the subsurface layer. While the resistivity sounding method aims to study variations in the resistivity of the subsurface layers of the earth vertically. The resistivity method by mapping uses the Wenner configuration, while the resistivity method by sounding uses the Schulmberger configuration. With this geoelectric study, it is hoped that it can become a reference for the feasibility study of the Samarinda tunnel which has an impact on the efficiency and effectiveness of tunnel construction, both in terms of cost and construction time. [ABSTRACT FROM AUTHOR]

Water is the main need of living things, including humans. The presence of water greatly affects daily life in human activities. Along with population growth, the need for water is getting bigger every year. This cannot be accomplished solely by relying on surface water alone. An alternative that can be done is to rely on the benefits of groundwater in confined aquifer zones, in addition to increasing the quantity of water quality standards, it can also improvewater quality. To determine the existence of a groundwater zone in a confined aquifer zone, a subsurface investigation is necessary. The dipole-dipole geoelectric method can see changes in the subsurface based on its resistivity. In the research area, namely in the pondok quran Islamic boarding school area, resistivity below the value of 10 ohm.m is indicated as a zone of water density, resistivity above 80 ohm.m indicates igneous rock and values 10 - 80 ohm.m are indicated for soil and sandstone. The geoelectric results of the dipole dipole are used as a reference for drilling, the closest area to drill is 30 m from the surface, right above the Pondok Quran Islamic boarding school. After drilling as deep as 35 m, the optimal discharge is 1,5 ltr / second and has a very good quality than surface water, namely pH 7, smelles, tasteless, temperature around 230 C, TDS around 300 Mg / L and the turbidity is 15 NTU. [ABSTRACT FROM AUTHOR]

Soil as the basis for strengthening the building structure must have a high bearing capacity and shear strength. Soil is useful as a building material in a variety of civil engineering and mining works. The main function of soil is to support the foundation of a building requiring stable soil conditions, poor soil conditions need to be engineered by changing or adding elements or materials that can change physical and mechanical properties by stabilizing the soil. Stabilization is an action taken to improve the physical and mechanical properties of the soil to increase the bearing capacity of the soil, water content, cohesion and internal friction angle. Soil stabilization that can be done, one of which is adding chemicals by adding extinguished lime (Ca(OH)2. Lime is a material that contains substances that are able to neutralize the swelling and shrinkage properties and increase the strength and durability of the soil, especially in clay soils with parameters of soil shear strength (ϕ) and cohesion (c) will increase and change the physical properties of the soil related to the volume of the optimum water content. The research was conducted by mixing extinguished lime with clay at 4%, 6%, 8%, 10%, and 12% and the direct shear strength test time was based on 3, 6, 9, and 12 days. Clay soil used as a mixture of quenched lime (Ca(OH)2) has a natural density value of 2.05 gr/cm3, 37.4% porosity, and a void ratio value of 0.6. The optimum water content value obtained in clay soil is 17.26% at a dry density condition of 2.38 gr/cm3. The effect of adding lime and a long test time on the optimum cohesion value occurred in the addition of 6% lime with a value of 0.15 MPa while the effect of adding lime and soil test time on the optimum internal friction angle value occurred in the addition of 12% lime with the highest value of 27.1o. [ABSTRACT FROM AUTHOR]

In the hydrological cycle, there is a water circulation process starting from evatranspiration, condensation, precipitation followed by run-off, infiltration and percolation. From this cycle it is known that water changes form startingfrom a liquid, solid and vapor. In the hydrogeological process, it is the process of obtaining groundwater which will produce groundwater basins. Hydrodynamics can be defined as the science that studies the motion of liquids or the motion of liquid fluids, especially the motion of water. The hydrodynamics of groundwater flow in the Subang groundwater basin in the form of lateral flow is regional flow and is an interbasin flow, where the Subang Groundwater Basin is related to the Non Groundwater Basin area which contains rock formations that act as a fissure medium. Where the groundwater flow pattern of the wells and the location of the springs found in the Non Groundwater Basin Zone indicates the direction of subsurface flow is to flow laterally to the Subang Groundwater Basin. By delineating the watertable (groundwater level), deep groundwater (bore well) and shallow watertable (dug wells and springs) in the Subang Groundwater Basin, it can be seen that the equal position of the watertable at the same location between dug wells and wells is in one aquifer system. the same one. In addition, several areas within the Subang Groundwater Basin are known to be able to absorb local and local water, especially in unconfined aquifer systems which are characterized by the similarity of the watertable positions of dug wells and drilled wells. The role of rock formations capable of absorbing water (infiltration), is also a reference for delineating the recharge zone of the Subang Groundwater Basin. [ABSTRACT FROM AUTHOR]

Bandung have unique geological conditions, one of which is surrounded by a mountainous complex composed of igneous rock. Understanding of the process of forming igneous rocks is very important because it can calculate the resources and spread of minerals economically. The method used in this research is petrographic analysis and geochemical analysis using the XRF (X-ray fluorescence spectrometry) method. Based on the results of field investigations, igneous rock in the Baleendah area is Andesite with a porphyritic texture and has a sheeting joint structure, massive and has a mineral composition of plagioclase, quartz, and pyroxene. Petrographic analysis was carried out on 6 rock samples and XRF was carried out on 4 rock samples, with the result of the type of magma that formed the rock in the study area was calc alkaline. The origin of magma based on regional tectonics comes from a depth of approximately 138.14 – 145.96 km below the earth's surface in the Island Arc Calc area. The results of the research with the type of sediment in the form of lava, generally andesite in the Baleendah area generally has a wide distribution and the best method to maximize existing resources is the site hill quarry mining method. [ABSTRACT FROM AUTHOR]