Mapping the Physical Properties of Soils and the California Bearing Ratio (CBR) Value for Different Soil Types: A Case Study in the Bukit Kemuning and Pugung Tampak Areas

It is widely accepted that soil is a mixture of mineral constituents that have accumulated over time. The physical characteristics of soil vary according to the mineral and organic matter content and the process of formation. The soil`s unique characteristics have been the subject of research in the field of civil engineering, which has continued to evolve to the present day due to the land`s requirement for civil engineering construction, such as road paving. As a result, the current study sought to determine the similarity of soil samples based on their physical properties and California Bearing Ratio (CBR) values, as well as the relationship between the soil`s physical properties and CBR values. To our knowledge, there is hardly little research in the literature investigating the topic under our investigation. Furthermore, we also mapped the physical characteristics and CBR values of numerous distinct soil samples using a Geographical Information System (GIS). This study concentrated on the West Lampung Regency, specifically the area between Bukit Kemuning in Central Lampung and Liwa in West Lampung, along the lines of Bukit Kemuning, Liwa, and Krui, all the way to the Lampung – Bengkulu province border. The soil samples from the area were taken for two tests: the unsoaked CBR test and the soaked CBR test. The results of the tests show that a 31-kilometre distance does not result in a significant difference in soil properties, which are generally similar except in clay-rich areas. Furthermore, the results of the laboratory analysis show that the amount of water in the soil sample affects the Liquid Limit (LL), Plastic Limit (PL), Maximum Dry Density (MDD), and CBR values; the lower the plastic limit value, and thus the lower the CBR value, the less water in the soil. The implications of the current findings are also discussed.

Recycled Polyester Geosynthetic Influence on Improvement of Road and Railway Subgrade Bearing Capacity— Laboratory Investigations

After years of using geosynthetics in civil engineering and infrastructure construction, it has recently become necessary to consider the possibility of recycling and reusing these materials. This paper presents the results of laboratory tests of the effect of recycled geogrid on the bearing capacity of soils using a CBR test. A polyester geosynthetic was selected for testing due to its high resistance to biodegradation and wide application. In a series of laboratory tests, two types of road and railway subgrade were used, mixed with geosynthetic cuttings in two different weight concentrations. The aim of the research was to demonstrate whether old demolition geosynthetics could be used to strengthen road and rail subgrade as recycled material. The influence of the geosynthetic cutting shape was also considered. The obtained results confirm the possibility of using recycled geogrid to improve the bearing capacity of the pavement subgrade, at least under these laboratory conditions. In the case of sand, the use of 2.0% additive causes that the poorly compacted soil obtains sufficient bearing capacity for the layer of road improved subgrade. As expected, the level of this improvement depends on the type of soil and the shape of geogrid cuttings.

Comparison of California Bearing Ratio (CBR) Value Based on Cone Penetration Test (CPT) and Dynamic Cone Penetrometer (DCP)

In civil engineering, land is important because as a place for building infrastructure to be built, so that the building infrastructure on it is stable, adequate carrying capacity is needed. The amount of soil bearing capacity can be determined in several ways, including the California Bearing Ratio (CBR) Field Test, Cone Penetration Test (CPT) and Dynamic Cone Penetrometer (DCP). The CBR and DCP tests are often used to determine the level of surface soil density on road structures, while CPT is usually used to determine the hard soil layer on the building structure. However, in certain situations Sondir and DCP data are often used to predict the CBR value, because the test is quite practical and efficient compared to the CBR test. CBR testing requires heavy equipment which in most small-scale projects is not available. In this study, we compared the CBR value based on the data obtained from the Sondir and DCP tests. Data collection was carried out in Surakarta and its surroundings. Based on the test results, the CBR value generated from the DCP test tends to be smaller than that from the CPT test with a ratio of 0.62: 1. This study resulted in the relationship between CBR values from the results of the CPT and DCP tests shown in the following equation: CBR (DCP) % = 0.2552 CBR(CPT) + 2.6306 and CBR (DCP) % = 0.617 CBR(CPT).

Effect on CBR Values with Addition of Coir Geotextile and Marble Dust in Silty Sands

The subgrade is the foundation of pavement. The conventional method of replacing weak soil with good soil can cause an increase in the cost of a project. Due to this reason ground improvement techniques are much popular nowadays. The major goal of this research work is to compare California Bearing Ratio (CBR) values of the virgin soil and soil reinforced with coir geotextile in one layer and a combination of two layers at different heights from the top surface of the soil. To see the change in CBR values one layer of coir geotextile was reinforced at three different heights (i.e., H/3; H/2 and 2H/3). After that, the effect on CBR values by reinforcement of combination of two layers of coir geotextile at different heights (i.e., H/3 and H/2; H/2 and 2H/3; and H/3 and 2H/3) from the top surface of the soil was studied. Thereafter, the soil is replaced by various percentages of marble dust ranging from 10% to 25% with an increment of 5% and again CBR values of soil samples reinforced with one layer of coir geotextile and a combination of two layers of geotextile at three different heights were compared with virgin soil. The test results reviewed that the maximum dry density (MDD) decreased and optimum moisture content (OMC) increased with the replacement of marble dust in the soil. The CBR test results specify an enhancement of the value of CBR with the addition of coir geotextile and marble dust. The maximum value of CBR is obtained when one layer of coir geotextile was introduced at the height of H/3 and in the case of a combination of two layers of coir geotextile maximum CBR values is obtained when the coir geotextile was introduced at a height of H/3 and 2H/3 from the top surface of the soil.

Improvement of bearing capacity of clay that is stabilized with bamboo charcoal powder

A building construction must be built on the soil with good bearing capacity. Increasing of bearing capacity of the soil can be done by adding material of soil stabilizer. Bamboo charcoal powder was used in this study as a stabilizer for clay. The percentage of the addition of bamboo charcoal powder to clay soil in this study was 5%, 10%, and 15%. The California Bearing Ratio (CBR) test was carried out on original clay and stabilized clay to determine the bearing capacity of the soil. The results of this study as showed an increase in the CBR value of each percentage of the addition of bamboo charcoal powder. The highest CBR value was the addition of 15% bamboo charcoal powder with an increase in the CBR value of the original clay by 82.87%. The increase in the CBR value of the soil indicates that there is an increase in the bearing capacity of the clay due to the addition of bamboo charcoal powder

Comparative Assessment of Deformation Under Plate Bearing Test and CBR Test for Subgrade Soil

A significant variation in the strength and deformation behavior of subgrade soil when tested in the laboratory and in the field. However, correlation of such variables is essential to evaluate the quality of the constructed subgrade. An attempt has been made in the present investigation to assess the deformation of control and stabilized subgrade soil in the laboratory and in the field. California bearing ratio (CBR) test was conducted in the laboratory and the static plate bearing test (PBT) was conducted in the field. Subgrade soil samples were stabilized with 6% lime, 17 % Cationic Emulsion, and combination of lime and emulsion. Similar stabilization was conducted at test sections in the field. The behavior of the control and stabilized soil in deformation under static PBT in the field and CBR in the laboratory was monitored and evaluated. It was noticed that polynomial correlation exists with high coefficient of determination between laboratory and field deformation for stabilized soil. It was observed that the deformation under CBR test decreased after implication of lime by (96 and 88) % for unsoaked and soaked testing conditions respectively. The deformation decreases by (92 and 85.6) % for unsoaked and soaked testing conditions respectively when emulsion was implemented. The deformation decreases by (91 and 88) % for unsoaked and soaked testing conditions respectively when combined stabilization was implemented. However, the deformation under PBT decreases by (75, 56, and 50) % for lime, emulsion, and combined stabilization processes respectively. It was concluded that testing condition (soaked or unsoaked) has no significant impact on the deformation of stabilized soil while it has a significant influence on the deformation of untreated soil under CBR test. On the other hand, the deformation of control soil shows no significant variation among field and laboratory testing in the model, however, the stabilized soil samples exhibit higher influence of field deformation on the polynomial models.

ANALISIS DAYA DUKUNG TANAH TERHADAP KERUSAKAN JALAN DI DESA BULUTIGO KECAMATAN LAREN KABUPATEN LAMONGAN

Road damage in Bulutigo Village, Laren District, Lamongan Regency affects access to agricultural mobilization in Lamongan Regency. So the researchers studied the value of the carrying capacity of the soil that caused road damage on the Bulutigo Village road, Laren District, Lamongan Regency. This study also examines the factors that affect the decline in the value of the bearing capacity of the soil. Data processing shows that the road subgrade soil in Bulutigo Village, Laren District, Lamongan Regency has a low carrying capacity value in terms of water content testing with an average value of 16.66% which includes high water content, from the Atterberg limit, it is included in the class of clay soil type. has a high plastic value with a PI value of 34.61%. Meanwhile, in the CBR test, the CBR value was 6.80% which was included in the "enough" category. And in the direct shear strength test, the value of the internal shear angle () is 15.03o.

EFFECT OF WASTE MATERIALS ON CALIFORNIA BEARING RATIO FOR GRANULAR BASE

It is known that paving is a system with multiple layers and the strength of each layer is reflected on the entire pavement. Two kinds of materials are used as the base layer, and the materials are divided into ordinary traditional granular materials and recycled materials such as foundry sand. This paper presents the results of laboratory tests in the laboratory and discusses the effect of each of the materials and foundry sand and its effect as a stabilizer on the strength of the substrate and as a stabilizer. Also, a comparison is made between the changes that occur in the base layer Cast sand treated and compared with untreated. A mixture of foundry sand with graded natural aggregate according to certain sizes is used as a stabilizer in proportions (5, 10 and 15) %. The treated and untreated base layer is compared in terms of strength. The base layer material is a traditional base material taken from the Nabaie quarry. Samples are made of three replicates of each possible group. Samples were prepared and subjected to a compressive strength CBR test. The obtained results indicate an increase in the resistance of the base material when using FS at a rate of (5%) with a treatment period of 4 days, while a ratio of 10% gave the highest resistance in a treatment period of 14 days, and these ratios gave more resistance than the untreated samples without the additive.