Applied Mechanics and Materials Vol. 802

Abstract: Uncontrolled growing of construction industry in Turkey has caused a large number of buildings were constructed without the benefit of sufficient engineering supervision. These phenomena have contributed to the increase in the number of seismically weak buildings. After the Great Marmara Earthquake seismic performances of the existing structures have been inspected and some of them fortified. In this context, an existing building foundation, built on a problematic soil and located in Denizli where is in high seismic risk area, has been strengthened by cement injection. Grouting holes up to 7 m in depth from the basement level were used in 45 points. The injection has created a less permeable barrier, acts like an underground dam. This barrier has caused rising of the underground water table around the recharge area of the foundation. The raised underground water has increased hydraulic gradient and hydraulic pressure. Then, the basement floor has arched up to 12 cm and underground water has risen up to 30 cm high after one year of the injection practice. In this study, hydrogeological characteristics of the soil structural analysis have been evaluated and some solutions suggested remedying the problem. It should be kept in mind as injection practice is employed in aquifers.

Abstract: Vegetation has been proven for establishing and implementing resistive measures against erosion and failure of slopes, river banks, removal of air pollution and reduced storm water runoff. Installation of cover crop involved soil element usage as growth medium which create several interaction between both strands. This study was carried out to investigate the soil strength performance by using Guinea grass at different construction period up to three months. Grass was planted in a 300 mm x 300 mm x 700 mm test plot with a suitable soil medium. Direct shear tests were conducted for each plot to determine the soil shear strength according to different construction period. Some basic geotechnical testing also were carried out. The results showed there is an increment in shear strength for soil sample over the time at various depths. During period of 1st, 2nd and 3rd month, the average shear stress of 100 mm depth was 50.56 kPa, 63.96 kPa, and 96.59 kPa respectively. Meanwhile, for 200 mm depth the result was 40.843 kPa, 53.91 kPa and 62.93 kPa respectively. Lastly, on 300 mm depth, shear stress was 37.21 kPa, 51.09 kPa, and 59.27 kPa respectively. Based on the result, the higher shear strength was obtained at different construction period and at varying depths. From the observation, roots mass increased for different construction period. In terms of tensile strength, the diameter of the root affects the rate of resistance against the tensile forces. This indicated that the roots structure growth affects the soil shear strength.

Abstract: Tunneling under high overburden and in-situ stress may cause tunnel instability because of rock overstressing. Evaluating overstressing in deep hard rocks is crucial to minimize excavation risks. The excavation of the Pahang-Selangor Raw Water Transfer Tunnel is evaluated in this study. A potential overstressing problem is expected at a tunnel depth more than 500 m. Therefore, the possibility of rock overstressing is assessed based on the evaluations of in-situ stress measurement, rock strength, and actual observations during the tunnel excavation. An analytical method is used to analyze the behavior of the tunnel under high overburden stress based on rock strength and tangential stress factors. The empirical assessment approach to the observation of actual overstressing appeared to be valid for the prediction of overstressing. These approaches facilitate the reasonable prediction of tunnel behavior under different rock conditions, support systems, and overburden stresses, which serve as useful tools in the observational design and construction method of long and deep tunnels.

Abstract: Groundwater inflows represent a very important element in hydrological circulation. Water inflows in Pahang-Selangor Raw Water Transfer Tunnel have been analyzed for isotopes stable of δ²H and δ¹⁸O. 61 samples were collected, including Tunnel Seepage Water (TSW), surface water and hot spring water samples within the study area which to understand the effect of multi topographical scale and geological characteristic. Deuterium (δ²H) and Oxygen-18 (δ¹⁸O) contributes the understanding of the origin and flow paths of water in the mountainous region. The δ²H and δ¹⁸O data obtained from TSW samples ranging from-45.73%₀ to-54.68%₀ and-46.01%₀ to-58.49%₀ are clustered along the local meteoric water line (LMWL) indicating that the groundwater originated from meteoric water. δ²H and δ¹⁸O data, primarily indicate the recharge altitude from 100m–550m which control by the sub vertical flow path mainly from geological structures (i.e. fractures and faults) followed by the groundwater. The altitude effect is indicated by the relation between the stable isotope values and elevation in meters highlighting a depletion of the heavy stable isotope with the increase of the tunnel overburden. The general trend obtained is δ²H and δ¹⁸O decreased with the increase of the overburden. The deviation of the δ²H and δ¹⁸O data from the expected trends may reflect the recharges are coming from the sub-horizontal flow path such as rivers or water infiltration from the valley. The results show that environmental isotopes indicates a better understanding of the complex hydrogeological system in a mountainous region and interaction between groundwater in granitic and meta-sedimentary rock formation along the tunnel project.

Abstract: The demand of surface area increases rapidly in the urban areas due to the increase in populations. This leads to the shortage of surface area for development in the future. Underground development is one of the solutions to solve the problems, such as the tunnel constructed underground, to provide new spaces for the development without claiming valuable spaces on the surface. Since construction of tunnel might influence the integrity of above ground structures, it is important to evaluate the impact of tunneling towards adjacent building foundation. This paper presents the numerical analysis of pile-tunnel interaction under greenfield condition for the optimization of tunnel distance, position and size relative to pile. Parametric study concerning the pile-tunnel interaction was concluded to assess the differential stress around the tunnel, ground settlement bending moment and axial force acting on pile. Pile-tunnel interaction was found directly proportional to the tunnel diameter and inversely proportional to pile-tunnel distance. The maximum surface settlement was observed at the tunnel with diameter of 1.5 times diameter (d). The highest pile bending moment and axial forces was observed at pile-tunnel distance equal to 1d.

Abstract: Establishment of ground motion prediction model that is able to accurately predict ground motion for Peninsular Malaysia is always a challenge to local researchers due to the paucity of strong ground motion data. In this study, Fukushima and Tanaka (1990) model which was identified as the best prediction model in estimating ground motion in Peninsular Malaysia due to earthquakes originated from Sumatra subduction zone in previous study was modified in order to enhance its performance. Multiple regression analysis was conducted based on supplementation of 212 seismograms, which were produced by 32 subduction events ranging from Mw 5.2 to 9.1 from Sumatra. The modified Fukushima and Tanaka model is expected to perform well in estimating ground motion from NEHRP Class C and D in the distance range of 300 to 1200 km. The appropriateness of the modified model was verified with actual ground motion in Peninsular Malaysia and also through comparison with other published models that are popular in the region.

Abstract: This study presents microzonation of the Denizli city center, is about 225 km2. It is mainly rely on t seismic velocities of the tested soil. For seismic microzonation area of has been selected as the study area. Seismic refraction methods have been used to generate two-dimensional profiles at 310 locations. These p and s wave velocities are used to estimate boundaries of the velocities at every 2 and 5 m intervals up to a depth of 60 m. The results are satisfactory for urban planning and it can successfully be used in urban areas. The municipal authority may be considered to use the results for land use studies.

Abstract: A middle size experiental wave generator has been implemented is the Ujikawa Open Laboratory, Disaster Prevention Research Institute, Kyoto University. The generator is composed of a pistontype wave maker, a head strage water tank and a current generator to mainly reproduce long waves like tsunami and storm surge.The paper desribes severalexperimental series to predict the applicability of the generator to model tests. The three operating sysemes are capable to be controlled in one operating sysytem and start time is contorolled separately according with the target tsunami and storm surge profiles. A sharp tsunami profile is reproduced in adjusting the start timing of piston type wave maker and opening gates of head storage tunk. Any type of tsunami waves are reproduced in the generator and it becomes a strong tool to predict the effective of ”resiliency” of hardwares.

Abstract: The study aims to investigate the flow characteristics of Newtonian and power-law non Newtonian fluids by using the dam-break of finite extent problem. Analytical and numerical studies are carried out to clarify the flow characteristics. In the analytical study, shallow flow equations are used to derive the characteristic in the viscous flow region for both the Newtonian and power-law non-Newtonian fluids. A numerical model based on the Volume of Fluids (VOF) method with higher order numerical scheme is used to verify the analytical findings. The study derived the flow characteristics based on the propagation of front position and the attenuation of flow depth at the dam upstream boundary.