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"This book explains the hypoplastic modelling framework. It is divided into two parts, the first of which is devoted to principles of hypoplasticity. First, the basic features of soils mechanical behaviour are introduced, namely non-linearity and asymptotic properties. These features are then incorporated into simple one-dimensional hypoplastic equations for compression and shear. Subsequently, a hypoplastic equivalent of the Modified Cam-Clay model is developed in 2D space using stress and strain invariants to demonstrate key similarities and differences between elasto-plastic and hypoplastic formulations. Lastly, the mathematical structure of hypoplastic models is explained by tracing their historical development, from the early trial-and-error models to more recent approaches. In turn, Part II introduces specific hypoplastic models for soils. First, two reference models for sand and clay are defined. After summarising their mathematical formulations, calibration procedures are described and discussed. Subsequently, more advanced modelling approaches are covered: the intergranular strain concept incorporating the effects of small strain stiffness and cyclic loading, viscohypoplasticity for predicting rate effects, soil structure to represent structured and bonded materials and soil anisotropy. The book concludes with a description of partial saturation and thermal effects: topics that are increasingly important to the disciplines of energy and environmental geotechnics.Selecting a constitutive model and its parameters is often the most important and yet challenging part of any numerical analysis in geotechnical engineering. Hypoplasticity involves a specific class of soil constitutive models, which are described in detail here. The book offers an essential resource, both for model users who need a more advanced model for their geotechnical calculations and are mainly interested in parameter calibration procedures, and for model developers who are seeking a comprehensive understanding of the mathematical structure of hypoplasticity."

"Tesis ini membahas pemodelan numerik untuk perilaku interface terhadap beban monotonik (geser). Analisis dilakukan dengan menggunakan model Direct Shear Test oleh karena kemudahannya. Pemodelan numerik dilakukan dengan menggunakan program Fast Lagrangian of Continua (FLAC) Code. Model konstitutif interface yang dipakai adalah Modifikasi Mohr Coulomb dengan Fungsi Hiperbolik. Secara umum, model ini dapat mensimulasi perilaku interface terhadap beban geser. Pada kasus pasir padat (dense), interface mengalami kontraktansi diikuti dengan dilatansi. Untuk pasir lepas (loose), interface hanya mengalami kontraktansi saja selama pembebanan geser. Untuk memodelkan kontraktansi dan dilatansi pada interface digunakan Hukum Dilatansi. Kajian lebih lanjut menyimpulkan bahwa pada kondisi batas yang berbeda, maka plastisitas pada CNV muncul terlebih dahulu kemudian diikuti dengan CNS kemudian CNL. Munculnya pola deformasi berbentuk lenticular juga terlihat pada zona interface setelah pembebanan geser. Studi aplikasi pada tiang pancang menggarisbawahi bahwa asumsi untuk properti interface tentunya akan mempengaruhi perilaku sistem tiang pancang.

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This thesis presents a numerical model to study the behavior of the interface under monotonic loadings (shearing). The Direct Shear Model was used in the analysis because of its simplicity. The numerical model was performed by using Fast Lagrangian of Continua (FLAC) Code. The interface model used here is the Modified Mohr Coulomb Model with a hyperbolic Law. In general, this model is sufficient to simulate the interface behavior. Under shearing, the interface exhibits contractancy followed by dilatancy in the case of dense sand. For the loose sand case, the interface experience contractancy throughout shearing. The generation of contractancy and dilatancy was created by using a simple dilatancy law. A further study with different boundary condition outlined that the yielding state in CNV test starts at the very beginning, then followed by the CNS and the CNL test. The occurence of a lenticular shape was also observed in this study. This explains the deformation shape of the interface zone after shearing. An application to a pile foundation system outlined that the interface strength and the density of the soil influence the pile responses."

"Several studies have already been published in order to better understand the behaviour of interfaces. Different experimental methods, including direct shear tests, simple shear test, and tortional ring test, and also various constitutive models were presented to modelize the behaviour of the interface. These studies revealed that the main factors that affect the behaviour of the interface include the roughness of the interface, the soil mineralogy, the soil density, and the normal stress applied. This work was therefore directed primarily to better understand the overall behaviour of the interface and the influence of these factors in a monotonic and cyclical solicitation. Through the simulation of a direct shear test at constant normal stress (CNL) in FLAC 5.0, several typical behaviours, including degradation of shearing resistance and contractancydilatancy, have been observed and modelled. At first, the law of Mohr-Coulomb and its correspondent failure criterion have been implemented. Then several models have been proposed to model more precisely the behaviour. Finally, two cyclicals laws, the law of Ramberg-Osgood law and Byrne, originally developed for the soil, have been implemented in this model. This study has verified the consistency of the results and has determined whether the injection of such laws is sufficient to modelize the behaviour of the interface under cyclic loading. "

"Peningkatan seismic demand di Indonesia khususnya pulau Jawa mengharuskan peningkatan perencanaan bangunan tahan gempa di Indonesia. Spun pile merupakan fondasi yang paling sering digunakan di Indonesia sebagai struktur bawah belum memasukkan konsep perfomance-based design sehingga struktur masih berperilaku elastis dan kurang ekonomis. Studi pemodelan pushover analysis dengan software Opensees berdasarkan hasil uji eksperimen dilakukan untuk mendapatkan pemodelan yang tepat serta dengan memasukkan efek tanah untuk melihat pengaruhnya terhadap perilaku spun pile seperti parameter daktilitas, pembentukan plastic hinge, dan level kinerja menurut ASCE 61-14. Pembebanan aksial (0.1fc’Ag) didapatkan pemodelan dengan material concrete 07 untuk beton spun pile yang didefinisikan confined dalam sengkang untuk spun pile dengan beton pengisi memberikan hasil yang lebih mendekati hasil eksperimen. Hasil dari kuat geser tanah yang semakin tinggi meningkatkan kekuatan pile-soil system dan daktilitas dari spun pile serta lokasi dari sendi plastis kedua di dalam tanah. Berdasarkan ASCE 61-14, level kinerja spun pile saat terjadinya sendi plastis masih berada dalam level minimal damage.

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The increasing of seismic demand in Indonesia, especially in the Java region, requires increased planning for earthquake-resistant buildings. The spun pile, as the commonly used substructure in Indonesia, is not implementing a performance-based design concept, therefore resulting in elastic behavior and less economical. A pushover analysis modeling study using Opensees software based on experimental test results was performed to get the right modeling and also to see its impact on spun pile behavior, such as ductility parameters, plastic hinge formation, and performance level by including soil effect according to ASCE 61-14. The result of modeling using material concrete 07 for spun pile concrete which is given an axial load of 0.1fc’Ag and defined as confined for spun pile with infill concrete, is closer to the experiment results. The result of the higher shear strength of the soil increases the strength of pile-soil system and ductility of the spun pile, as well as the location of the second plastic hinge in the soil. According to ASCE 61-14, the performance level of the spun pile when the plastic hinges occur is minimal damage."

"Kemungkinan kejadian kegempaan di Indonesia sangat tinggi sehingga diperlukan struktur fondasi yang mampu menahan beban gempa dengan baik. Oleh karena itu, pada penelitian ini dilakukan studi pemodelan fondasi grup tiang dengan memasukkan pembebanan lateral sebagai simulasi beban gempa. Pemodelan ini memperhatikan keluaran berupa interaksi antara tiang fondasi dengan tanah pada tanah lempung. Selain itu, keluaran yang diperhatikan adalah seismic behavior berupa daktilitas dan kejadian sendi plastis yang dialami oleh tiang fondasi. Studi pemodelan dilakukan dengan mengacu pada penelitian Yuwono et al. (2020), di mana model fondasi grup tiang dibuat pada tanah lempung dengan variasi kuat geser undrained tanah 20 kPa, 40 kPa, 60 kPa, 80 kPa, dan 100 kPa. Pada penelitian ini, keluaran-keluaran yang diperhatikan mengikutsertakan pengaruh dari variasi kuat geser undrained tanah tersebut. Model tanah dan tiang dimodelkan dalam pendekatan nonlinier P-y dari Beam-on-Nonlinear-Winkler-Foundation (BNWF) melalui aplikasi OpenSees. Melalui pemodelan tersebut, dilakukan validasi penelitian terhadap model fondasi penelitian Yuwono et al. (2020)berdasarkan kurva pushover yang terbentuk. Dari penelitian ini, semakin besarnya nilai kuat geser undrained tanah maka kecenderungan nilai daktilitas lendutan semakin besar. Lalu, semakin besarnya nilai kuat geser undrained tanah juga mempercepat terjadinya sendi plastis pertama dan lebih memungkinan menghasilkan kejadian sendi plastis kedua. Nilai kuat geser undrained tanah yang semakin besar juga meningkatkan nilai gaya dalam momen bending dan aksial pada tiang-tiang fondasi. Pada penelitian ini, tidak terjadi kegagalan geser sama sekali pada seluruh tiang namun terjadi kegagalan lentur untuk lead pile pada tanah dengan kuat geser undrained tanah 100 kPa. Selain itu, terbentuk momen guling untuk fondasi grup tiang pada tanah dengan kuat geser undrained tanah 20 kPa dan 100 kPa. Adapun secara performa, nilai P-Multiplier yang semakin besar membuat peran tiang menjadi lebih besar pada sistem fondasi grup tiang dan semakin besarnya nilai kuat geser undrained tanah akan cenderung meningkatkan nilai faktor efisiensi grup.

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The possibility of earthquakes in Indonesia is very high, so a foundation structure that can withstand earthquake loads is adequately needed. Therefore, in this study, a pile group foundation modeling study was conducted by including lateral loading as a simulation of earthquake loads. This model pays attention to the output in the interactions between the foundation piles and the soil on clay soil. In addition, the output considered is seismic behavior in the form of ductility and the occurrence of plastic hinges experienced by the foundation piles. The modeling study was conducted with reference to the research of Yuwono et al. (2020), in which the pile group foundation model is made on clay soils with variations in the undrained shear strength of the soil 20 kPa, 40 kPa, 60 kPa, 80 kPa, and 100 kPa. In this study, the observed outputs include the effects of variations in the undrained shear strength of the soil. The soil and pile models were modeled in the P-y nonlinear approximation of the Beam-on-Nonlinear-Winkler-Foundation (BNWF) via the OpenSees application. Through this modeling, research validation was carried out on the research foundation model of Yuwono et al. (2020) based on the pushover curve formed. From this study, the greater the value of the undrained shear strength of the soil, the greater the tendency of the deflection ductility value. Then, the greater the value of the undrained shear strength of the soil also accelerates the occurrence of the first plastic hinge and is more likely to produce a second plastic hinge occurrence. The greater the value of the soil's undrained shear strength also increases the force's value in bending and axial moments on the foundation piles. In this study, there was no shear failure on the entire pile but flexural failure for the lead pile on the soil with an undrained shear strength of 100 kPa. In addition, the overturning moment is formed for pile group foundations on soils with undrained shear strengths of 20 kPa and 100 kPa. As for performance, the larger the P-Multiplier value, the greater the role of the pile in the pile group foundation system, and the greater the value of the undrained shear strength of the soil will tend to increase the value of the group efficiency factor."

"ABSTRAKPile breakwater is an alternative coastal structure to prevent coastal erosion considering the economic and technical aspect. An improved design for pile breakwater is proposed here. Our goal is to develop an assessment tool in planning the implementation of pile breakwater. This tool is based on numerical model that has been verified with physical model result. The wave spectrum show that the numerical model is able to simulate the wave as same as the physical model with overestimation. It also points out that the simulation with wave period (T) = 2.5 s has more significant noise than the simulation with wave period (T) = 2 s. In general, the numerical model has high accuracy for predicting incident wave height (Hi), transmitted wave height (Ht) and transmission coefficient (KT) with error below 1 % RMSE. Xbeach is also able to simulate pile breakwater with high accuracy especially for two or three row arrangement with width gap 0.3 m. Even so, the numerical model have limitation regarding wave phase and wave through irregularity. Pile breakwater is an alternative coastal structure to prevent coastal erosion considering the economic and technical aspect. An improved design for pile breakwater is proposed here. Our goal is to develop an assessment tool in planning the implementation of pile breakwater. This tool is based on numerical model that has been verified with physical model result. The wave spectrum show that the numerical model is able to simulate the wave as same as the physical model with overestimation. It also points out that the simulation with wave period (T) = 2.5 s has more significant noise than the simulation with wave period (T) = 2 s. In general, the numerical model has high accuracy for predicting incident wave height (Hi), transmitted wave height (Ht) and transmission coefficient (KT) with error below 1 % RMSE. Xbeach is also able to simulate pile breakwater with high accuracy especially for two or three row arrangement with width gap 0.3 m. Even so, the numerical model have limitation regarding wave phase and wave through irregularity. "