Posts Tagged ‘geotechnical’

17
Aug

Do Geotechnical Failures occur? Can it be prevented?

Written by Gouw Tjie Liong, Ir., M.Eng, ChFC, PhD. Posted in Note and Discussion

Geotechnical failures do happen, either small or large scale, sometimes, even with fatalities.  To prevent it to happen, the following steps must be taken:

  1. Appoint a capable geotechnical engineer (expert) to assess the problem at hand.
  2. Carry out an adequate, proper and systematical soil investigation as pointed by the geotechnical engineer.
  3. Analyze, interpret and derived the geotechnical design parameters based on the the available soil data. In a large construction geological and seismicity of the area must also be assessed.
  4. Asses and understand what type of construction to be built, and also the possible loading imposed to the ground.
  5. Carry out the short term and long term stability and deformation of the planned geotechnical structure.
  6. While building the structures (geotechnical structures), install geotechnical field instrumentation (examples: piezometer, inclinometer, pressure cells, etc). Carry out proper and systematical monitoring based on the installed geotechnical instrumentation. Interpret the data properly.
  7. Re-analyzed the performance of the structure and compare it with the design (prediction) made prior to construction. If necessary make the necessary correction. Admit the error when we, as an engineer, made an error in prediction / calculation and immediately seek a remediation. And if necessary ask for help from a more experience engineer.
  8. In handling a new type of problem which are complex and difficult, it is better to seek for an advice from fellow capable engineers.
  9. Be honest to ourselves and never pretend to be clever on everything.

Jakarta, July 31, 2011

16
Aug

Sheetpile Baja atau Beton untuk di Pantai?

Written by Gouw Tjie Liong, Ir., M.Eng, ChFC, PhD. Posted in Note and Discussion

Maradona Don: kalu kita desain pelabuahn sebaiknya mengggunakan steel sheet pile atau concrete sheet pile, mengingat di pinggir pantai ada korosi? Tahap2 melakukan pendeteksian parameter tanah untuk pelabuhan, uji apa saja yg dilakukan?

Saran GTL:
Sebagai guideline bisa jawaban saya adalah sbb:

  1. Keduanya bisa digunakan. Namun sheet pile perlu menggunakan yang namanya cathodic protection untuk mencegah korosi, atau sistem anti korosif lainnya. Beton sheet pile mungkin bisa lebih murah, namun bahan beton harus dibuat dari semen tipe dua yang biasa digunakan di pantai.
  2. Sebagai uji pendahuluan diperlukan test tanah sbb: SPT, sondir, beberapa borelog, katakan setiap 100m satu borelog, setiap 50m satu sondir. Ambil undisturbed sample setiap 2-3m.
  3. Buat profile dan perkiraan parameter tanah berdasarkan hasil step 2.
  4. Buat design pendahuluan (preliminary design) dari sistem penahan tanah.
  5. Berdasarkan step 2,3, dan 4, buat lagi soil investigation yang lebih terfokus. Bila tanah bersifat pasiran, konsentrasikan untuk mencari nilai phi efektif yang lebih baik. Ini bisa dilakukan dengan mengambil sample secara teliti dan melakukan direct shear test. Bila tanah bersifat kohesif, usahakan mengambil sampel untuk melakukan uji triaxial CU dengan melakukan pengukuran tengangan air pori. Dari sini bisa didapatkan nilai c’ dan phi’ yang representatif (dengan catatan pengujian baik). Bila perlu, lakukan uji pressuremeter, dari uji ini bisa didapatkan koefisien tekanan tanah dalam keadaan diam, Tekanan tanah dalam keadaan diam, Yield Pressure (tegangan leleh) dan P ultimate yang sangat berguna untuk mendapatkan nilai E yang diperlukan untuk analisa pergerakan sheet pile.
  6. Bila dipandang perlu sebagai pelengkap lakukan uji tambahan tsb setiap jarak 50m.
  7. Catatan: perlu dicari lapisan tanah keras untuk penjepitan sheet pile.
  8. Lakukan review design dan matangkan design untuk pelaksanaan.
16
Aug

Testimonial on Geotechnical Course: Earth Pressure-Slope Stability-Deep Excavation-Liquefaction-GEO5

Written by Gouw Tjie Liong, Ir., M.Eng, ChFC, PhD. Posted in Contents, Testimonials

Sonya Probo Arum (Geoforce Indonesia):  “After joining the course, the results are well beyond my expectation. The course material is very insightful. The presentation is not monotonous and easy to digest, it was combined with real cases. Negligence of designing stage and the consequences that cause geotechnical failures are well presented. Not only that, as a senior geotechnical engineer, Mr. Gouw also convey tips and messages that does not give the impression as lecturing but are very useful ingredient to be a competent geotechnical engineer. Thanks Mr. Gouw ” (August 16, 2011)

Khori Sugianti (Research Center for Geotechnology LIPI): “Thank you for the training given. That was a very useful course to enhance our knowledge.” (August 15, 2011)

Geotechnical Course

  • Soil Mechanis
  • Soil Investigation
  • Foundation Engineering
  • PIT, PDA, Sonic Logging
  • Slope Stabilization
  • Geotechnical Instrumentation
  • Deep Excavation
  • Ground Improvement
  • Geotechnical Instrumentation
  • Earthquake
  • Liquefaction Analysis
  • Application of Geotechnical Software
  • Other Geotechnical Course

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Motivational Course

  • Cultivating Engineering Judgment
  • The Problem of Engineer
  • How I Present Myself
  • Light Up
  • Toward Successful Engineering Career
  • Pressure lead to Success
  • The Up and Down of My Life
  • Theory of Emptiness
  • Turning Thought into Reality
  • Young Engineer