The Friction Coefficient of Cohesive Soils and Geotextile: An Approach Based On the Direct Shear Test Data

The soil reinforcement designing by using geotextile requires the friction coefficient of soil-geotextile interface, both granular and cohesive soils. For cohesive soils, this coefficient was usually defined by [⅔ tan f]. Is this approach efficient enough or conservative? This paper presents an approach to determine the friction coefficient of soil-geotextile interface based on the empirical data from some researchers. It was used direct shear test data on cohesive soil-geotextile interfaces. Result show that the friction coefficient of soil-geotextile interface higher than the value of tan f. It was also proved by the interface friction angle d tend to higher than the soil internal friction angle f. Hence, the approach by [⅔ tan f] would be yield excessive safety design, which the safety factor would be added for soils and geotextiles. The new approach in determining the interface friction coefficient was conducted by using direct relationship between interface friction coefficient and soil internal friction angle

Behavior of Uplift Resistance of Single Pile Row Nailed-Slab Pavement System on Soft Clay Sub Grade

Nailed-slab Pavement System is a new kind of rigid pavement which proposed by Hardiyatmo (2008). This system consists of a thin reinforced concrete slab, and short piles attached underneath. The installed piles under the slab were functioned as slab stiffeners and anchors. Its performance due to compression loadings were conducted by some researchers. Puri, et.al (2015) reported pull out test on 1-pile row Nailed-slab System. In this paper, the finite element analysis will be done by using the test results from Puri, et.al (2015). According to Puri, et.al (2015), the full scale of 1 pile row Nailed-slab System was conducted on soft clay which consisted of 6.00 m x 1.20 m slab area with 0.15 m in slab thickness, 5 short micro piles (0.20 m in diameter, 1.50 m in length, and 1.20 m in pile spacing) as slab stiffeners which installed under slab. Piles and slab were connected monolithically, then in due with vertical concrete wall barrier on the two ends of slab. The system was loaded by pull out loading on the end of slab. The tested model has sufficiency uplift resistance and linear elastic behavior can be reached the load 13.3 kN (Puri, et.al, 2015). Behavior of Nailed-slab Pavement System can be good modeled in linear elastic zone. Contribution of vertical barrier due to pull out loading should be taken in further research. Anchorage resistance of piles was contributed to the uplift resistance. This uplift capacity is very important to resist the uplift loads around the end of sla

Infrastruktur Jalan Beton Sistem Pelat Terpaku Untuk Pembangunan Jalan Berkelanjutan Pada Tanah Dasar Lunak dan Ekspansif

Conventional rigid pavement on soft soil needs more thickness of slab which increases self weight, and it is unbeneficial for soft soils. The pavement of Nailed-slab System has been proposed by previous researcher as an alternative solution for pavement on soft soils. This system is not a soil improvement method, but rather as an alternative method to improve the performance of rigid pavement on soft soils. The installed piles under the slab were functioned as slab stiffeners. This paper is aimed to inform the performance of Nailed-slab System on soft clay, its consideration forprospect of practical application, and designing method.The full scale Nailed-slab System was conducted by Puri (2015a) on soft clay which consisted of 6.00 m x 3.54 m slab area with 0.15 m in slab thickness, 15 short micro piles (0.20 m in diameter, 1.50 m in length, and 1.20 m in pile spacing) as slab stiffeners which installed under slab. Piles and slab were connected monolithically, then in due with vertical concrete wall barrier on the two ends of slab. The system was loaded by vertical monotonic and repetitive loadings. One pile row Nailed-slab was also conducted and tested by compression and pull out loadings. Results show that the installed piles under the slab which embedded into the soils were functioned as slab stiffeners and were able to response similarly in 3D. Observed differential settlements were very small. This system has higher resistance due to vibration. Good performance was also shown by this system due to uplift load, as well as swelling pressures of expansive soils. Thereby, the Nailed-slab system is promising for practical application. Hence, it is needed conducting of a field trial on a road section laid over soft clay or expansive soil

The Friction Coefficient of Cohesive Soils and Geotextile: An Approach Based on the Direct Shear Test Data

The soil reinforcement designing by using geotextile requires the friction coefficient of soil-geotextile interface, both granular and cohesive soils. For cohesive soils, this coefficient was usually defined by [⅔ tan Is this approach efficient enough or conservative? This paper presents an approach to determine the friction coefficient of soilgeotextile interface based on the empirical data from some researchers. It was used direct shear test data on cohesive soil-geotextile interfaces. Result show that the friction coefficient of soil-geotextile interface higher than the value of tan . It was also proved by the interface friction angle tend to higher than the soil internal friction angle . Hence, the approach by [⅔ tan would be yield excessive safety design, which the safety factor would be added for soils and geotextiles. The new approach in determining the interface friction coefficient was conducted by using direct relationship between interface friction coefficient and soil internal friction angle

Analisis Numerik Perkerasan Pelat Terpaku Tiang Tunggal Menggunakan Tiang Pipa Baja Pada Lempung Lunak

All of the full-scale tests and numerical analysis of Nailed-slab System from previous researchers used massive reinforced concrete piles. This research will study the possibility of steel pipe pile as a replacement of massive reinforced concrete piles if there are available enough steel pipe piles. This research is aimed to study the behavior of single steel pipe pile Nailed-slab System on soft clay and the inuence of pile length due to slab deection and soil stresses. It was used the data from Puri (2015a) for a single massive reinforced concrete pile Nailed-slab. This massive reinforced concrete pile was replaced by a single steel pipe pile with similar and varied diameter which analyzed by the 2D nite element method. Results show that the steel pipe pile can be used as a “nail” at the Nailed-slab pavement system but by a larger dimension compared to the massive reinforced concrete pile. The maximum effective shear stress in soil did not reach undrained shear strength under a standard wheel load 40 kN. Generally, the soil was not failure

Studi Parametrik Perkerasan Jalan Beton Sistem Pelat Terpaku Pada Tanah Dasar Lunak

Theapplications of chiken foot foundation (sistem cakar ayam) are shown successfully on run way, taxi way, and apron of airport and gave services more than 30 years. This system is also shown the satisfy performance for high way construction. One of developing of this system was changing the concrete cylindrical foundation by galvanized cylindrical steel and it is named modified chiken foot foundation (CAM). Hardiyatmo (2008) proposed Nailed-slab System for more practical application by changing the cylindrical foundation by concrete pile foundation. Based on model tests and analysis, the Nailed-slab is promising for application. This research is aimed to learn the behavior of Nailed-slab by conducting parametric study. This study was using the full scale test results of chiken foot foundation in Waru, East Java. Results show that the performance of Nailed-slab system (4 × 4 piles and 5 × 5 piles)with similar slab width with CAM was better than CAM performance. Slab deflections of Nailed-slab tend to be lower than CAM. Similar behaviorswere for moment of slab. Additional of pile length and decreasing the pile spacing can increase the performance which indicated by decreasing the deflections

Developing Curve of Displacement Factor for Determination of Additional Modulus of Subgrade Reaction on Nailed-Slab Pavement System

The pavement of the nailed-slab system has been proposed as an alternative solution for addressing the rigid pavement problem in soft soils. This system is used for developing a rigid pavement. The simple method of using an equivalent modulus of subgrade reaction (k’) in nailed-slab system analysis was proposed by a previous researcher. This modulus consists of the modulus of subgrade reaction from a plate load test (k) and an additional modulus of subgrade reaction due to pile installing (k). The additional modulus of subgrade reaction has been proposed by some authors. The displacement factor was used in determining the additional modulus of subgrade reaction. This factor is difficult to define. In this research, the prototype test of a nailed slab with single-pile installation was conducted to learn the validation of the theory of the additional modulus of subgrade reaction on a full-scale dimension. The prototype was constructed on soft clay, and the connection between the pile and slab was perfect monolithically. This system was loaded by centric load. A new curve of the displacement factor is proposed. Calculated deflections based on this curve were compared to the observed deflection and resulted in good agreement with the observation. Hence, it can be used in preliminary design

Uji Beban Horizontal Perkerasan Jalan Sistem Pelat Terpaku Tiang Tunggal Pada Lempung Lunak

Perkerasan kaku tidak hanya menerima beban searah gravitasi akibat tekanan roda kendaraan dan beban temperatur, namun juga beban horizontal akibat pengereman. Penelitian ini ditujukan untuk mengetahui perilaku perkerasan kaku Sistem Pelat Terpaku akibat beban horizontal. Ditinjau Pelat Terpaku tiang tunggal dengan skala model 1 : 1 pada lempung lunak. Dimensi pelat adalah 120 cm x 120 cm x 15 cm dan di bawahnya dipasang tiang tunggal berdiameter 15 cm dengan panjang 150 cm. Di bawah pelat juga diberi lantai kerja setebal 5 cm. Hubungan pelat dan tiang dibuat monolit dan diperkuat pelat penebalan berukuran 40 cm x 40 cm x 20 cm. Beban horizontal diberikan di tengah pelat dan diamati deformasi lateral pelat. Hasil pengujian menunjukan bahwa Pelat Terpaku tiang tunggal berperilaku linier elastik hingga beban 10,4 kN. Adapun defleksi lateral pada beban tersebut sebesar 0,52 mm. Perilaku plastik mulai terbentuk di atas beban 10,4 kN yang diiringi kecepatan peningkatan defleksi lateral pelat