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11 votes

Pembinaan kerja luar tersebut dijalankan setelah pemendapan sudah minima.

Apakah kaedah digunapakai untuk mengetahui anggaran masa bagi pemendapan mencapai minima?


in Geotechnical 8,120 points 25 56 91
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1 Answer

5 votes
We can start our civil works after the ground treatment works completed.

How to know when it is completed?

If the Ground treatment involved Surcharge with PVD, is after the designer confirm the consolidation process achieved 90% or the settlement is minimal by confirmation  from instrumentation on site!

Thus, take care of the soil instrument & make sure we verified the readings!

Always verified back by the designer, there are cases where the treatment duration have completed but somehow the settlement is still active!...
500 points 4 9
Saya ada pengalaman projek Lebuhraya NNKSB (Pelabuhan Klang) dimana walau pun settlement melebihi 90% telah dicapai namun setelah longkang dan dipasang settlement masih berlaku dan menyebabkan longkang dan manhole tergantung. Mungkin nilai 10% tersebut terlalu besar bagi kawasan tersebut.

90% consolidation is based on the JKR Needs Statement which consider that remaining 10% settlement will take a very long time to achieve. If we plot Time vs Settlement, the remaining 10% is nearly flat and asymptote (the line approach 0 or nearly infinity)

There are at least 2 aspects to consider :

  1. Magnitude of settlement
  • If the calculated total settlement = 300 mm. 10% remaining settlement is 30.0 mm. Thus, the magnitude of settlement after treatment is not significant. Most building component can tolerate it!
  • If the calculated total settlement = 1500 mm. Remaining settlement (10%) would be 150 mm of half a feet! The magnitude of settlement may not favorable to certain building components. 
  • I use the word calculated total settlement because the actual settlement must be monitor on site (via soil instrument) and be verified by competent Geotechnical Engineer!
  1. Rate of settlement (mm/day , mm/months or mm/year)
  • Even the treatment nearly achieving 90%, the rate of settlement must be monitor. At least we can predict during DLP or after 5 years of project completion, the remaining settlement still acceptable!
  • The rate of settlement must be analyze by using actual settlement reading & not by prediction.
My past experience handling soft soil in Klang, Muar, riverbank of Melaka, Sarawak etc, the settlement is more than 1.0 m and proper assessment of the site & project must be done by competent Geotechnical Engineer.