A VUMAT of modified Mohr-Coulomb model and its application in TBM tunnelling simulation

Author(s):  
Meidong Han ◽  
Zongxi Cai ◽  
Yitong Zhang ◽  
Chuanyong Qu ◽  
Kui Chen
Keyword(s):  
Author(s):  
Mate Antali ◽  
Gabor Stepan

AbstractIn this paper, the general kinematics and dynamics of a rigid body is analysed, which is in contact with two rigid surfaces in the presence of dry friction. Due to the rolling or slipping state at each contact point, four kinematic scenarios occur. In the two-point rolling case, the contact forces are undetermined; consequently, the condition of the static friction forces cannot be checked from the Coulomb model to decide whether two-point rolling is possible. However, this issue can be resolved within the scope of rigid body dynamics by analysing the nonsmooth vector field of the system at the possible transitions between slipping and rolling. Based on the concept of limit directions of codimension-2 discontinuities, a method is presented to determine the conditions when the two-point rolling is realizable without slipping.


2003 ◽  
Vol 13 (08) ◽  
pp. 1185-1217 ◽  
Author(s):  
Olivier Bokanowski ◽  
Benoît Grebert ◽  
Norbert J. Mauser

We deal with local density approximations for the kinetic and exchange energy term, ℰ kin (ρ) and ℰ ex (ρ), of a periodic Coulomb model. We study asymptotic approximations of the energy when the number of particles goes to infinity and for densities close to the constant averaged density. For the kinetic energy, we recover the usual combination of the von-Weizsäcker term and the Thomas–Fermi term. Furthermore, we justify the inclusion of the Dirac term for the exchange energy and the Slater term for the local exchange potential.


Author(s):  
Fei Ye ◽  
Yu-Feng Wei ◽  
Shao-Ping Yang ◽  
Xing-Yu Yuan ◽  
Xia Ming ◽  
...  
Keyword(s):  

2020 ◽  
Vol 10 (5) ◽  
pp. 6220-6223
Author(s):  
A. H. Bhutto ◽  
G. S. Bhurgri ◽  
S. Zardari ◽  
M. A. Zardari ◽  
B. A. Memon ◽  
...  

The settlement calculation of a multi-story building is a challenging task due to the variation of soil properties and the use of an appropriate constitutive model for the reliable representation of soils’ stress-strain behaviors. In this study, the settlement response of a multi-story building was calculated with the simple Mohr-Coulomb Model (MCM) and the Hardening Soil Model (HSM). The effect of soil modulus of elasticity using both models was investigated on the overall settlement response of the building. Results indicated that MCM overestimated immediate settlement in a range of 50 to 65% compared to HSM. The settlement response of the building calculated with both models was within the allowable range. The results of this study can be helpful for geotechnical engineers working on reliable predictions of the settlement of multi-story buildings.


2018 ◽  
Vol 4 (1) ◽  
Author(s):  
Hadianti Muhdinar Pasaribu

Banyaknya pembangunan infrastruktur yang merupakan salah satu tolak ukur kemajuan suatu daerah menyebabkan terjadinya penyempitan lahan didaerah tersebut. Sehingga pemanfaatan ruang dan lahan sangat dibutuhkan untuk menunjang kemajuan pesatnya pembangunan infrastruktur. Salah satu inovasi terbaik dalam mengatasi masalah keterbatasan lahan adalah membuat bangunan bawah tanah sehingga memberi ruang yang lebih untuk pembangunan. Pembangunan yang cukup terbaru di Indonesia saat ini adalah pembangunan MRT (Mass Rapid Transit) yang dilakukan di Jakarta. Pembangunan ini dalam pelaksanaannya membutuhkan proses konstruksi terowongan (tunneling) dan galian dalam untuk tiap stasiunnya. Pada penelitian ini, penulis terpusat terhadap masalah galian dalam pada stasiun Senayan dari proyek konstruksi MRT Jakarta. Permasalahan terbesar dalam suatu pekerjaan galian dalam adalah adanya deformasi lateral pada dinding bangunan bawah tanah dalam hal ini yang digunakan adalah dinding diafragma (D-Wall) dan juga adanya penurunan tanah disekitar galian. Oleh karena itu, perlu dilakukan pengecekan agar tidak terjadi keruntuhan. Metode konstruksi yang digunakan pada stasiun Senayan adalah metode konstruksi Top-Down. Pada penelitian ini dilakukan analisis deformasi horizontal dan penurunan tanah menggunakan software Plaxis 3D dengan dua pemodelan tanah, yaitu model tanah Mohr Coulomb dan Hardening Soil. Hasil deformasi horizontal yang diperoleh menggunakan model tanah Hardening Soil lebih mendekati  monitoring dilapangan dibandingkan dengan model tanah Mohr-Coulomb. Penelitian ini berfokus pada bagian-bagian tepi pada dinding diafragma melengkapi jurnal sebelumnya yang berfokus pada titik tengah dari dinding diafragma. Besarnya deformasi horizontal pada tahap akhir galian (penimbunan kembali tanah hingga dasar muka tanah) di titik P#80 (di tepi dinding diafragma) tercatat pada monitoring inclinometer sebesar 4.15 mm, dan deformasi yang dihasilkan menggunakan model Hardening Soil sebesar 9.57 mm sedangkan  menggunakan model Mohr-Coulomb sebesar 16.05 mm. Hasil deformasi horizontal yang diperoleh menggunakan model tanah Hardening Soil lebih mendekati  monitoring dilapangan dibandingkan dengan model tanah Mohr-Coulomb meskipun hasil yang diperoleh cukup jauh dari monitoring dilapangan.  Kata Kunci : Galian Dalam, Deformasi Horizontal, Model Mohr Coulomb, Model Hardening Soil, Plaxis 3D  The number of infrastructure development which is one of the benchmarks of the progress of a region causes the narrowing of land in the area. So that the utilization of space and land is needed to support the rapid progress of infrastructure development. One of the best innovations in overcoming the problem of land limitations is to make the underground building giving more space for development. The most recent development in Indonesia today is the construction of MRT (Mass Rapid Transit) conducted in Jakarta. This development in its implementation requires tunneling and deep trenching process for each station. In this study, the authors centered on the deep trenching problems at the Senayan station from the Jakarta MRT construction project. The biggest problem in a deep trenching work is the lateral deformation of underground building walls in this case which is used diaphragm wall (D-Wall) and also the decrease of soil around the excavation. Therefore, it is necessary to check to avoid collapse. The construction method used in Senayan station is a Top-Down construction method. In this research, horizontal deformation and soil degradation analysis using Plaxis 3D software with two soil modeling, Mohr Coulomb and Hardening Soil soil model. The result of the horizontal deformation obtained using Soil Hardening Soil model is closer to monitoring the field compared to the Mohr-Coulomb soil model. This study focuses on the edges of the diaphragm wall complementing the previous journal focusing on the midpoint of the diaphragm wall. The magnitude of the horizontal deformation at the final stages of excavation (backfill) to P # 80 (on the edge of the diaphragm wall) was recorded in inclinometer monitoring of 4.15 mm, and the resulting deformation using the Hardening Soil model of 9.57 mm while using the Mohr model -Coulomb of 16.05 mm. The horizontal deformation results obtained using the Soil Hardening Soil model is closer to the field monitoring than the Mohr-Coulomb soil model although the results obtained are quite far from the field monitoring.Keywords: Deep Excavation, Horizontal Deformation, Mohr Coulomb Model, Hardening Soil Model, Plaxis 3D.


2014 ◽  
Vol 90 (8) ◽  
Author(s):  
M. Hohenadler ◽  
F. Parisen Toldin ◽  
I. F. Herbut ◽  
F. F. Assaad
Keyword(s):  

2019 ◽  
Vol 97 ◽  
pp. 04006
Author(s):  
Nataliia Lobacheva ◽  
Vadim Griniov

The necessity to take into account the properties of soil foundations, which depend not only on the conditions of their natural occurrence, but also on the stress state, led researchers to create a large number of different soil models. This article provides is to clarify the patterns and features of the three-dimensional interaction of strip foundations with the soil base in conditions of dense urban development with the use of various design soil models and comparison with field observations. Three soil models (the Mohr-Coulomb model, the Hardening-Soil model, model of the Klepikov stiffness coefficient) are considered. The calculation stages displayed a true picture of the construction of a new building (dismantling of the floor of an existing building, excavation, etc.). As a result of numerical experiments with a use of Plaxis and methods for calculating structures on a deformable base was received values settlement of strip foundations in applying three soil models. The difference of the calculated values of strip foundation settlement is defined in percentage. The geodesic monitoring confirms the validity of the research.


2013 ◽  
Vol 671-674 ◽  
pp. 357-362
Author(s):  
Hai Ming Liu ◽  
Jing Cao ◽  
Wei Feng Zhang

With the continuous development of urban underground space, the environmental effects of foundation pit excavation have been paid extensive close attention. Unfortunately, there are few researches in mucky soil and peaty soil. Adopted the software of FLAC-3D, the ground deformation due to the foundation pit excavation is simulated. Considering the characteristic of the soil, the Modified Cam-clay model and Mohr-coulomb model are used during the simulation. Meanwhile, the structure units are used to simulate foundation pit structure. The results of the field measurement and numerical simulation suggest that the influenced range soil is about 2.7 times of the excavation depth. Furthermore, the Modified Cam-clay model can obtain a better result to simulate the mucky soil and peaty soil in Kunming. The results can be referred to design and construct of foundation pits.


2015 ◽  
Vol 94 ◽  
pp. 01080 ◽  
Author(s):  
Stephane J. Marcadet ◽  
Christian C. Roth ◽  
Borja Erice ◽  
Dirk Mohr

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