scholarly journals Coupled hydro-mechanical influence on hydraulic conductivity of well-graded sandy gravel

2021 ◽  
Vol 9 (8) ◽  
pp. 394-397
Author(s):  
Chenghao Chen ◽  
Shiang Mei ◽  
Yi Tang ◽  
Shengshui Chen
2015 ◽  
Vol 52 (10) ◽  
pp. 1526-1538 ◽  
Author(s):  
Yong-Xia Wu ◽  
Shui-Long Shen ◽  
Ye-Shuang Xu ◽  
Zhen-Yu Yin

This paper presents a case history of the leakage behavior during dewatering tests in the gravel strata of an excavation pit of a metro station in Hangzhou, China. The groundwater system at the test site is composed of a phreatic aquifer underlain by an aquitard and a confined aquifer with coarse sand and gravel. The sandy gravel stratum has very high hydraulic conductivity. The maximum depth of the excavation is 24 m below the ground surface, which reaches the middle of the aquitard strata, where the thickness of the clayey soil is insufficient to maintain the safety of the base of the excavation. To understand the hydrological characteristics of gravel strata, single- and double-well pumping tests were conducted, where a cut-off wall was installed 43 m deep with its base penetrating 2 to 3 m into the aquifer. Test results show that this partial cut-off of the aquifer cannot effectively protect the base of the excavation from the upward seepage force of the groundwater during excavation. Therefore, a new cut-off wall (second phase) was constructed to a depth of 54 m to cut off the confined aquifer. A second pumping test was conducted after the construction of the second phase cut-off wall, and test results show that this full cut-off combined with dewatering can control groundwater effectively during excavation. This finding indicates that when a deep excavation is conducted in a confined aquifer with high hydraulic conductivity, determination of the depth of the retaining wall should be based on three factors: the stability of the base, the upward seepage stability, and settlement control.


Author(s):  
Jen Cendy Wakim ◽  
Grace Loupatty ◽  
Josephus R. Kelibulin

Gempa bumi adalah suatu peristiwa bergetarnya bumi akibat pelepasan energy di dalam bumi yang di tandai dengan adanya patahan lapisan batuan pada kerak bumi. Energy yang di hasilkan di pancarkan ke segalah arah berupa gelombang gempa bumi sehingga efeknya dapat di rasakan sampai ke permukanaan bumi, serta seringkali menimbulkan kerugian dan kerusakan pada bangunan. Penelitian ini dilakukan di desa Erie yang terletak di kecamatan nusaniwe kota ambon, penelitian ini dilakukan bertujuan untuk mengetahui fase – fase gelombang dan indeks kerentanan seismik. Pengambilan data dilakukan dengan menggunakan seismograf TDL 303S pada 6 titik pengukuran. Hasil pengukuran mikrotremor di analisis menggunakan metode Horizontal to Vertical Spectar Ratio ( HVSR) untuk memperoleh nilai frekuensi dominan (f0) factor amplikasi (Ao), sehingga nilai kerentangan seismic (Kg) dapat di tentukan. Dari hasil penelitian ini menunjukan bahwa nilai frekuensi dominan (f0) 0.646 Hz sampai 9.531 Hz, nilai amplikasi (Ao) 0.977 sampai 1.559, dan nilai indeks kerentanan seismik diperoleh 0.233 (Kg)  samapai 2.113 (Kg), dan dari hasil pengolahaan data juga di peroleh nilai priode dominan dari setiap titik pengukuran, sehingga dari nilai priode dominan tersebut menunjukan bahawa pada titik pengukuran 1,5 dan 6 dapat di kategorikan sebagai sendimen yang lunak dan tersusun atas batuan Alluvial, yang terbentuk dari sendimen delta, toposoil, lumpur dengan kedalaman 30 m atau lebih dan pada titik pengukuran 2,3 dan 4 dapat di kategorikan tersusun atas batuan alluvial dengan kedalaman 5 m. terdiri dari sandy-gravel, sandy-hard clay,loam. Dengan demikian desa Erie tidak tergolong daerah yang rawan merusak bangunan.


2020 ◽  
Vol 53 (2) ◽  
Author(s):  
Guanglong Zhu ◽  
Lifeng Gu ◽  
Yu Shi ◽  
Huize Chen ◽  
Yuqian Liu ◽  
...  

Soil Horizons ◽  
1986 ◽  
Vol 27 (2) ◽  
pp. 32
Author(s):  
Thomas A. Peragallo ◽  
Steven P. Schertzer

2003 ◽  
Vol 67 (1) ◽  
pp. 373
Author(s):  
Lalit M. Arya ◽  
Feike J. Leij ◽  
Peter J. Shouse ◽  
Martinus Th. van Genuchten

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