Uplift Mechanism of Rectangular Tunnel in Liquefied Soils

2016 ◽  
pp. 61-74 ◽  
Author(s):  
Chung-Jung Lee ◽  
Yue-Chen Wei ◽  
Wen-Ya Chuang ◽  
Wen-Yi Hung ◽  
Wen-Lung Wu ◽  
...  
Keyword(s):  
Liquefied Soils ◽  
Rectangular Tunnel

scholarly journals Three-Dimensional MIMO Channel Model with High-Mobility Wireless Communication Systems Using Leaky Coaxial Cable in Rectangular Tunnel

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Kai Zhang ◽  
Fangqi Zhang ◽  
Guoxin Zheng ◽  
Lei Cang
Keyword(s):  
Wireless Communication ◽  
Communication Systems ◽  
Channel Model ◽  
Mimo System ◽  
Three Dimensional ◽  
High Mobility ◽  
Coaxial Cable ◽  
Mimo Channel ◽  
Wireless Communication Systems ◽  
Rectangular Tunnel

With the rapid development of high-mobility wireless communication systems, e.g., high-speed train (HST) and metro wireless communication systems, more and more attention has been paid to the wireless communication technology in tunnel-like scenarios. In this paper, we propose a three-dimensional (3D) nonstationary multiple-input multiple-output (MIMO) channel model with high-mobility wireless communication systems using leaky coaxial cable (LCX) inside a rectangular tunnel over the 1.8 GHz band. Taking into account single-bounce scattering under line-of-sight (LoS) and non-line-of-sight (NLoS) propagations condition, the analytical expressions of the channel impulse response (CIR) and temporal correlation function (T-CF) are derived. In the proposed channel model, it is assumed that a large number of scatterers are randomly distributed on the sidewall of the tunnel and the roof of the tunnel. We analyze the impact of various model parameters, including LCX spacing, time separation, movement velocity of Rx, and K-factor, on the T-CF of the MIMO channel model. For HST, the results of some further studies on the maximum speed of 360 km/h are given. By comparing the T-CF between the dipole MIMO system and the LCX-MIMO system, we can see that the performance of the LCX-MIMO system is better than that of the dipole MIMO system.

scholarly journals PERANCANGAN FONDASI TIANG PANCANG PADA TANAH BERPOTENSI LIKUIFAKSI DI SULAWESI

2020 ◽  
Vol 3 (3) ◽  
pp. 865
Author(s):  
Markus Jusuf ◽  
Aksan Kawanda
Keyword(s):  
Soil Layer ◽  
Cyclic Stress ◽  
Lateral Spreading ◽  
Soil Pressure ◽  
Spreading Effect ◽  
Cyclic Resistance ◽  
Cyclic Resistance Ratio ◽  
Liquefied Soils ◽  
Moment Effect ◽  
The Moment

ABSTRACTIndonesia is a country located in the most active earthquake paths in the world. This makes Indonesia prone to earthquakes and has the potential to experience liquefaction. Liquefaction can cause pile failure, so several things need to be considered in designing piles on potentially liquefied soils. One project in Sulawesi has a profile of uniform grained saturated soil that is susceptible to liquefaction. Two things that need to be considered in the design of piles on potentially liquefied soils is to ignore the capacity of pile friction and calculate the moment due to lateral spreading effects. Calculation of liquefaction potential is done by comparing the ratio of the cyclic stress and the cyclic resistance ratio and is compared by four other methods namely: the Seed et al. (2003), Tsuchida (1970), Seed et al. (2003), and Bray & Sancio (2004). The lateral spreading effect is calculated by referring to the JRA Code where the liquefied soil layer gives pressure to the pile at 30% of the overburden stress and the soil layer above the liquefied soil gives passive soil pressure to the pole. The moment effect caused by lateral spreading results in the addition of dimensions or number of poles.Keywords: liquefaction; lateral spreading; bearing capacity; JRA Code; pile foundationABSTRAKIndonesia adalah negara yang terletak di jalur gempa teraktif di dunia. Hal ini menyebabkan Indonesia rawan gempa dan memiliki potensi untuk mengalami likuifaksi. Likuifaksi dapat menyebabkan kerusakan/kegagalan struktur yang sangat merugikan, sehingga perlu diperhatikan beberapa hal dalam merancang tiang pada tanah berpotensi likuifaksi. Salah satu proyek di Sulawesi memiliki profil tanah pasir berbutir seragam dan jenuh air yang memiliki potensi likuifaksi. Dua hal yang perlu diperhitungkan dalam perancangan tiang pada tanah berpotensi likuifaksi adalah mengabaikan daya dukung friksi tiang dan memperhitungkan momen akibat efek lateral spreading. Perhitungan potensi likuifaksi dilakukan dengan membandingkan rasio tegangan siklik (CSR) dan rasio hambatan siklik (CRR) serta dibandingkan dengan empat metode lainnya yaitu: metode Seed et al. (2003), Tsuchida (1970), Seed et al. (2003), dan Bray & Sancio (2004). Daya dukung aksial pada tiang pancang mengalami pengurangan 32% akibat lapisan tanah yang terlikuifaksi. Efek lateral spreading dihitung dengan acuan JRA Code dimana lapisan tanah terlikuifaksi memberikan tekanan ke tiang sebesar 30% dari tegangan overburden dan lapisan tanah di atas tanah terlikuifaksi memberikan tekanan tanah pasif ke tiang. Efek momen yang diakibatkan oleh lateral spreading mengakibatkan penambahan dimensi ataupun jumlah tiang.Kata kunci: likuifaksi; lateral spreading; daya dukung; JRA Code; fondasi tiang    

Local Site Investigation of Liquefied Soils Caused by Earthquake in Northern Thailand

2018 ◽  
Vol 24 (7) ◽  
pp. 1181-1204 ◽  
Author(s):  
Lindung Zalbuin Mase ◽  
Suched Likitlersuang ◽  
Tetsuo Tobita ◽  
Susit Chaiprakaikeow ◽  
Suttisak Soralump
Keyword(s):  
Site Investigation ◽  
Northern Thailand ◽  
Local Site ◽  
Liquefied Soils

Characteristics and Triggering Conditions for Naturally Deposited Gravelly Soils that Liquefied following the 2008 Wenchuan Mw 7.9 Earthquake, China

2018 ◽  
Vol 34 (3) ◽  
pp. 1091-1111 ◽  
Author(s):  
Longwei Chen ◽  
Xiaoming Yuan ◽  
Zhenzhong Cao ◽  
Rui Sun ◽  
Weiming Wang ◽  
...  
Keyword(s):  
Wenchuan Earthquake ◽  
Necessary Conditions ◽  
2008 Wenchuan Earthquake ◽  
Chengdu Plain ◽  
Wave Velocities ◽  
Shear Wave Velocities ◽  
Gravelly Soils ◽  
Triggering Conditions ◽  
Liquefied Soils ◽  
Favorable Conditions

The 2008 Mw 7.9 Wenchuan, earthquake caused naturally deposited ravelly soils to liquefy over a wide area. Although liquefaction of gravely soils is recognized by the geotechnical profession, observations of liquefaction and nonlique-faction case histories within the literature are few. Through several years of systematic study following the 2008 Wenchuan earthquake (Mw 7.9), 92 locations of gravel liquefaction were identified, described, and mapped. These locations lie within an approximately 3,000 km2 area of the Chengdu Plain. Peak ground accelerations estimated at the sites range from 0.15 g to 0.49 g. Taken collectively, these studies reveal the necessary conditions for liquefaction triggering in gravelly materials. Grain size analyses indicates that the ejecta was much finer than the gravels that liquefied. Gravel contents of liquefied soils ranged from 5% to more than 85%. The liquefied gravelly soils were loose, but their measured shear wave velocities range from 133 m/s to 267 m/s, with corrected values ranging from 154 m/s to 31 4m/s. The unique depositional conditions under Chengdu Plain provide favorable conditions for extensive liquefaction of gravelly soils. The shallow soil profiles consist of a 0.5 m to 5.5 m impermeable soil (i.e., the capping layer) overlying gravels ranging in thickness from a few meters to hundreds of meters.

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