The phenomenon of flooding that occurs in various parts of the world continues to increase, both in terms of frequency and amplitude. Without neglecting the morphology of the region, global climate change and changes in land use as a result of economic growth are the main factors causing this disaster. Understanding flood characteristics, be it discharge, inundation height, and their distribution in an area is very important as a basis for determining flood control efforts. This study aims to analyze the level of flood vulnerability based on the characteristics of the occurred floods. Hydrological and topographical analyzes were performed as the basis for the flow hydraulics calculations performed with Hec-RAS 2D version 5.0.7. The flood distribution simulation results with return periods of 2, 5, 10, and 25 years show that the area of ​​the village that has the potential to be inundated is ± 22.57 ha, ± 37.11 ha, ± 41.81 ha, and ± 47.27 ha, with inundation heights varying between 0.25 m. – 1.50 m, which can be classified as low to high hazard.

The conventional embankment has disadvantages in terms of its weight; it has an implication for the level of deformation that will occur on the subgrade layer. This study was conducted dealing with the design of geocomposite material compositions based on their mechanic characteristics. The lightweight geocomposit material (LWGM) was constructed by composing soil with expanded polystyrene (EPS) with by-product of buton asphalt as the binder agent (WBA). Unconfined Compression Test (UCT) and California Bearing Ratio (CBR) were examined to figure out the mechanical behavior of LWGM. The percentages of WBA used on specimens were 3%, 5%, 7% and 9%, while those of EPS were 0.15% and 0.30%, based on weight of soils dry density. Furthermore, to understand the curing period effect, all the specimens were cured and tested within 7 days and 28 days. The results showed that the LWGM could reduce the embankment densities from 20% to 35%, compared to conventional embankment. The compressive strength and CBR values presented the same tendency, so that, based on correlation of UCS and CBR value, the LWGM compositions that are appropriate for road foundation criteria as subbase courses are 3.2% to 7% for the WBA and 0,15% - 0,30% for the EPS.

Chemical soil stabilization is known as the most economical method compared to others. The development of stabilization materials has led to studies of the utilization of natural materials and waste materials to replace cement and lime which has become the most popular binder agent ever known. This research utilizes natural minerals such as overboulder, zeolite and Palm Oil Fuel Ash (POFA) as its binder agents. The amount of natural material varies at intervals 3% - 15% by the weight of soil. Additional of natural materials is done to increase bearing capacity as a subbase layer, which is based on FHWA standards CBR minimum is 20%. California Bearing Ratio (CBR) tests were carried out to see the effect of each material for increase bearing capacity of soft soil. Curing periode is varies at 7 days, 14 days and 28 days. The results shows, by adding natural minerals such as overboulder, zeolite, and POFA increasing the CBR value up to 5 times, 6 times and 5 times compared to untreated soil and close to the CBR value of cement stabilized soil. Referring to FHWA standards, we can conclude that natural materials can be used for stabilization materials on subbase layer.

Purpose: The advantage of lightweight concrete is to reduce the weight, which is considered the dead load on the structure. This study aims to determine the effect of replacing sand with pumice sand as fine aggregate in lightweight concrete. The substitution affects the compressive strength, split tensile strength, and weight.    Design/methodology/approach: The research method is through testing in the laboratory, where the test specimens are cylindrical following SNI with a height of 30 cm and a diameter of 15 cm totaling 50 pieces. The composition ratio between regular and pumice sand is 75%:25%, 50%:50%, 25%:75%, and 0%:100%, respectively. Control of the test object using 100% regular sand. Findings: This research shows that adding pumice sand into the mixture decreases the volume weight. The weight of the volume of concrete produced is < 1,900 kg/m3, which is classified as a lightweight one. Research limitations/implications: The resulting compressive strength of 56.63 kg/cm2 decreased against the control test object by 81.10%. At the same time, the split tensile strength is 1.13 kg/cm2, or a decline of 52.05% from the control test object. Originality/value: This paper is an original work. Paper type: Research paper

This study aims to analyze the deflection behavior of the sheet pile through experimental testing and numerical analysis using the Finite Element Method (FEM). The Laboratorium scale test on a Tub with length of 1500 mm, width of 600 mm, and height of 1500 mm, and Steel Plate 3.2 mm with dimensions of 1400 mm x 590 mm was used as a model of the sheet pile wall. The subgrade material is clay soil and embankment material in the form of Sirtu which passes the No. sieve. 40. Physical and mechanical testing of soil and gravel materials is carried out with reference to ASTM standards. The measurement of the value of the strip load (q) and deflection was carried out using a load cell with a capacity of 100 kN and a linear variable differential transformer (LVDT). The deflection of the sheet pile was using was analyzed using Plaxis 8.2 software of the FEM method. The results of laboratory tests show that the pile wall collapses at a load of 74 kN/m2, with a deflection of 24.56 mm, while the FEM analysis shows that the pile wall collapses at a load of 71 kN/m2 with a deflection of 21.29 mm.