A Construction of buildings on the beach is needed to provide facilities and infrastructure. An analysis of bearing capacity and foundation settlement for building construction is necessary to avoid structural failure. This study analyzed bearing capacity and foundation settlement on the East coast of Bangka Regency, Bangka Belitung Island Province, including Tikus Beach, Takari Beach and Karang Mas Air Anyir Beach, based on field data from Cone Penetration Test (CPT). Result showed that the level of soil consistency, bearing capacity, and foundation settlement can be analyzed by combining the structural loads for the 1 to 5 floor buildings. Bearing capacity of shallow foundation was calculated using the Meyerhof (1976) method, whereas the deep foundation is using the Meyerhof (1956) method. Settlement of shallow foundation was calculated using the Steinbrenner (1934) method, whereas the deep foundation is using the Vesic (1970) method. This study found the soil consistency levels at three locations had the range from medium to hard level. The analysis of foundation bearing capacity showed that the greater of soil bearing capacity, the smaller of foundation dimensions. The greater the load that must be held by the foundation, the greater the size of the foundation needed to withstand it. The analysis of the settlement showed that the smaller of the soil bearing capacity, the greater of settlement. The greater the load that must be withheld by the foundation, the foundation settlement will greater.

Clay is a soil with low stability, so an effort is needed to improve soil stability in order to improve the quality of subgrade. In this study, an effort was made to improve soil stability by adding gypsum waste and tin tailings as a mixture in clay. Gypsum waste and tin tailings have not been utilized optimally in Bangka Belitung Province, so the research needs to be done to determine the effect of using gypsum waste and tin tailings as a material for stability of clay. The tests of soil characteristics carried out in this study were sieve analysis, soil specific gravity, compaction and direct shear test. In this study, the addition of gypsum waste and tin tailings in soft soil with 4 variations, namely clay with additional 8% gypsum waste and 20% tin tailings, clay with additional 8% gypsum waste and 30% tin tailings, and clay with addition 8% gypsum waste and 40% tin tailing, besides that, testing of the original soil was also carried out. The results of sieve analysis test showed that the addition of gypsum waste and tin tailings to clay soils could change the gradation of clay. Addition of gypsum waste and tin tailings on clay soil increases cohesion (c) dan shear angel value so that increases soil shear strength. From the results of the study, the addition of gypsum waste and tin tailings can improve the stability of clay so Improve Quality of Subgrade.

In the construction of road construction, soil bearing capacity, such as the CBR value, needs to be considered. In clay soil, the CBR value of the soil is low, so that stabilization material can be added to its repair. In this study, the stabilization materials used were waste materials in the form of bagasse ash and eggshell powder. Variations in the mixture of bagasse ash mixture used in this study were 7%, 10%, and 13% plus 3% eggshell powder. Testing in this study includes testing moisture content, sieve analysis, specific gravity, consistency limits, compaction testing, and CBR. The soil classification system used is the Unified classification (USCS), a test guideline based on SNI. From the CBR soaked test, it was found that the CBR value of clay soil increased along with the increase in the percentage of bagasse ash plus 3% eggshell powder and the increase in collisions on the soil. The percentage increase in the CBR value of clay soil with a mixture of stabilization to clay soil is 92.303%. at 65 blow. So that bagasse ash and eggshell powder greatly affect the increase in the CBR value of clay soil.

Underground Coal Gasification (UCG) is a technology to extract coal deposits in the form of gas from mineral deposit without disassembling of overburden. There are some initial processes in UCG, one of them is cementing to glue the casing into the formation. This research-based laboratory using cement mixture that consists of Fire Mortar as the main ingredients with added Oil Well Cement (OWC) by 40%, 42.5%, 45%, 47.5%, 50%, 52.5%, 55%, 57.5% and 60% of the total weight of the cement mixture. Cement samples were then tested with hydration heat test, furnace test at  temperatures of 300°C to 900°C and UCS test of a sample at normal temperature as well as samples that have undergone combustion at a certain temperature. Composition of OWC>50% have faster setting time on the 29th to 40th hours with maximum hydration temperature of 34.4°C on the 11th to the 12th hour as well as getting the optimal composition of Fire Mortar which is 42.5% and OWC which is 57.5%. Composition of 50-60% Fire Mortar have a heat resistance to a maximum of 900°C so they don’t experience failure and cracks which make a sample split. Ofter than that, composition of 50-60% OWC on average have a greater compressive strength with the highest compressive strength value of 1.75 MPa at a temperature of 500°C.

Kabupaten Bangka merupakan kabupaten dengan wisata pantai yang sangat bagus namun belum di kembangkan secara optimal. Kajian pemetaan tanah sangat diperlukan untuk menyediakan informasi spasial kondisi tanah di Pesisir Pantai Kabupaten Bangka. Adanya pemetaan kondisi tanah ini bertujuan agar identifikasi awal dalam perencanaan suatu pekerjaan konstruksi dapat dilakukan dengan mudah, cepat dan tepat. Penelitian ini bertujuan untuk menganalisis kondisi tanah yaitu konsistensi tanah, kedalaman tanah keras serta klasifikasi tanah berdasarkan data sondir (CPT) di Pesisir Pantai Kabupaten Bangka. Pada penelitian ini digunakan data sekunder berupa data CPT, peta administrasi dan peta DEM Kabupaten Bangka. Data CPT yang digunakan berjumlah 18 titik uji di sepanjang pesisir pantai kabupaten Bangka. Nilai tahanan konus (qc) serta nilai rasio gesekan  (FR) hasil uji CPT pada lokasi penelitian di gunakan untuk menganalisis kondisi tanah. Metode interpolasi spasial yang digunakan pada penelitian ini adalah metode IDW (Inverse Distance Weighted) yang telah terintegrasi pada perangkat lunak ArcGIS. Hasil penelitian menunjukkan bahwa kedalaman tanah keras di Pesisir Pantai Kabupaten Bangka berdasarkan nilai tahanan konus (qc) berkisar antara 2,6 m – 7,72 m. Pada kedalaman diatas 3 meter  nilai tahanan konus sudah diatas 120 kg/cm2  yang menunjukkan  konsistensi tanah  keras (hard). Pada kedalaman tanah keras, klasifikasi tanah di di Pesisir Pantai Kabupaten Bangka  berdasarkan korelasi antara nilai Rasio Gesekan (FR) dengan nilai tahanan konus (qc) seragam yaitu  berupa tanah lempung