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"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."

"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."

"Horizontal shear interaction between profiled steel sheeting and concrete in composite slab is obtained through various means, such as frictional resistance due to indentation or embossment in the sheeting, interlocking at the steel and concrete interface resulting from curvature and shape of the sheeting profile under bending, and anchorage devices such as welded shear studs and crippled sheeting at the end of the span. Permanent end pour stops may provide some restraining effect to the slipping of the concrete, and hence may enhance the composite action. Despite the use of many types of devices, most reported test results of typical length composite slabs still exhibit partial shear interaction. This paper reports the enhancement of the horizontal shear interaction at the concrete-profiled steel sheeting interface of composite slab by using shear screws. Six full scale bending tests were conducted of which three specimens with different slenderness were enhanced with self drilling screws while another three were without screws. The test results show that the failure mode of composite slab can be improved to ductile type and the load carrying capacity can be increased by the presence of the shear screws. The load performance of the slab is also affected by the slenderness, which is the ratio of shear span to effective depth."

"Pada September 2018, kota Palu dilanda gempa dengan momen magnitude sebesar 7.5 yang mengakibatkan kerusakan dan korban jiwa. Gempa tersebut mengakibatkan beberapa fenomena lain, seperti tsunami dan likuifaksi. Beberapa pengujian pun dilakukan untuk memahmi respon dinamis dari tanah di kota Palu. Pada penelitian ini, dilakukan uji cyclic simple shear pada tanah berpasir yang didapatkan dari Desa Lolu, Sulawesi Tengah. Pengujian tersebut dapat menggambarkan getaran dari gempa bumi berupa gaya geser horizontal secara berulang. Pengujian ini dilakukan pada tiga variasi kepadatan relatif (30%, 50%, dan 70%) dengan nilai CSR sebesar 0.15, 0.20, dan 0.25. Selain itu, dilakukan pula pengujian lain untuk memberikan lebih banyak data untuk analisis, seperti specific gravity, grain size analysis, dan Atterberg limit. Hasil dari pengujian ini menunjukkan bahwa kepadatan relatif memiliki peran dalam liquefaction resistance – semakin tinggi kepadatan relatif dari sebuah sampel, maka akan semakin banyak jumlah siklus pembebanan yang diperlukan untuk mencapai failure. Namun, jika nilai CSR yang diberikan lebih tinggi pada sampel tersebut, maka akan semakin sedikit jumlah siklus yang dibutuhkan untuk mencapai kondisi yang sama.

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In September 2018, Palu city was hit by a 7.5-moment magnitude earthquake which caused damages and casualties. It triggered a tsunami, and liquefaction. Some tests have been recently performed to understand the dynamic response of Palu ground. In this study, cyclic simple shear tests were performed on sandy soils collected from Lolu Village, Central Sulawesi. This test could convincingly portray the real seismic ground shaking under repeated horizontal shear force. The tests were conducted at three variations of relative density (30%, 50%, and 70%) under CSR value of 0.15, 0.20, and 0.25. Other tests were conducted in this study to provide more data to the analysis, such as specific gravity, grain size analysis, and Atterberg limit. The results showed that relative density plays a role in liquefaction resistance—the higher relative density obtained for the samples, the higher number of cycles needed to reach failure. However, if higher CSR values given to the samples, the lower number of cycles needed to reach the same condition."

"Pencampuran enzim urease dan larutan penjenuh berupa urea dan kalsium klorida pada tanah pasir merupakan salah satu proses biogrouting yang merubah bentuk butiran pasir menjadi batuan pasir. Permasalahan dalam penelitian ini adalah seberapa besar pengaruh perubahan bentuk pasir terhadap parameter kuat geser pasir tersebut. Parameter kuat geser pasir berupa kohesi dan sudut geser. Uji direct shear dilakukan sesuai standar ASTM D 3080-03 untuk mendapatkan nilai kohesi dan sudut geser dari tanah pasir. Setelah transformasi butiran pasir menjadi batuan pasir terjadi, didapatkan hasil berupa kenaikan nilai kohesi yang menunjukkan ikatan partikel pasir yang semakin kuat. Pasir kontrol tanpa perlakuan pada penelitian ini memiliki kohesi sebesar 0 kPa dengan sudut geser 32,72 °, pasir yang telah tersementasi dan didiamkan selama 7 hari memiliki kohesi sebesar 317,01 kPa dengan sudut geser 33,27 ° , sedangkan pasir yang tersementasi dan didiamkan selama 14 hari memiliki kohesi sebesar 788,78 kPa dengan sudut geser 36,11 °.

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Adding enzym urease and cementation solution which consists of urea and calcium chloride is one of biogrouting process which transform particle of sand to become sandstone. Main topic on this paper is how big the effect of these transformation of sandstone in aspect to shear strength parameter on sand soil. Shear strength parameter consists of cohesion and friction angle of sand soil. Direct shear test is performed to follow ASTM D 3080-03. After the transformation done and formed the sandstone, increase in shear strength parameters are achieved. Control sands on this paper have 0 kPa cohesion value and friction angle of 32,72°. Sandstones with 7 days fermentation have cohesion value of 317,01 kPa with friction angle of 33,27°. Sandstones with 14 days fermentation have cohesion value of 788,78 kPa with friction angle of 36,11°"

"Penelitian ini bertujuan untuk mendapatkan parameter kuat geser sampah artfisial dengan melakukan pengujian direct shear yang dipengaruhi oleh beberapa karakteristik seperti ukuran pada sampah anorganik, perlakuan dalam pembuatan sampel sampah, dan kompresi awal sebelum pengujian. Hasil yang didapatkan berupa nilai kohesi sebesar 0-41,8 kPa dan sudut geser sebesar 0-26,68°. Pada sampah anorganik dengan ukuran kecil memiliki nilai kohesi yang lebih rendah dan sudut geser yang lebih tinggi dibandingkan sampah anorganik dengan ukuran besar. Selain itu, sampel sampah yang dikompresi awal 40 kPa memiliki nilai kohesi yang lebih tinggi dan sudut geser yang lebih rendah dibandingkan sampel sampah yang dikompresi 80 kPa. Sedangkan perlakuan dalam pembuatan sampel sampah tidak terlalu berpengaruh terhadap kohesi namun berpengaruh pada sudut geser. Hasil ini kemudian dibandingkan dengan penelitian sebelumnya dan dilakukan analisis balik dengan metode numerik menggunakan Plaxis.

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The objective of this study is to obtain shear strength parameters of artificial municipal solid waste using direct shear test while looking on effect of characteristics such as inorganic samples size, sample treatment when preparation, and initial compression before testing. The results for cohesion is 0-41.8 kPa and friction angle is 0-26.68°. The inorganic samples with small size has lower cohesion and higher friction angle than inorganic samples with large size. In addition, samples are compressed by 40 kPa has higher cohesion and lower friction angle than samples are compressed by 80 kPa. While on sample treatment when preparation does not significantly affect on cohesion but effect on friction angle. These results are then compared with the previous research and doing back analysis by numerical methods using Plaxis."

"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. "

"Estimasi kecepatan gelombang seismik shear (Vs) pada suatu log sumur menjadi kunci keberhasilan Studi pada lapangan yang tidak memiliki log Vs. Untuk itu pemahaman sifat Hsika batuan menjadi syarat utama dalam estimasi Vs. Pada Tugas Akhir (TA) ini dilakukan estimasi kecepatan gelombang seismik S dan aplikasinya untuk pemodelan penggantian fluida pada suatu reservoar. Estimasi Vs dilakukan dengan beberapa algoritma yaitu hubungan empiris, Castagna, Gassmann dan Xu-White.Hasil estimasi dari algoritma-algoritma tersebut memperlihatkan bahwa algoritma Xu-White memberikan hasil yang lebih tepat dibandingkan dengan beberapa metode lain. Hasil ini dapat dipahami karena Xu- White dalam perhitungannya memperhatikan faktor matrik batuan.

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Shear Wave estimation on the well log, which has no S-sonic log, become succesful key in the reservoir characterization. Therefore, the knowledge of petrophysical properties becomes the main prerequisite for estimating Vs. In this study, shear Wave estimation is performed and the estimated shear Wave is used to carry out Fluid Replacement Modeling. A number of algorithm is used to estimate the S Wave such as empirical relationship, Castagna, Gassmann and Xu-White.

The result shows that Xu-White algorithm, provide more accurate results compare to the other algorithms. This conclusion can be understood since the Xu-White algorithm consider the matrix of rock."