Transcript R.Karlinasari Mobilisasi Mudah  Tidak mengganggu lingkungan dengan getaran yang dapat merusak/ retak dinding bangunan sekitar proyek.  Pengoperasian alat sederhana.  Memenuhi syarat teknik.

R.Karlinasari
Mobilisasi Mudah
 Tidak mengganggu lingkungan dengan
getaran yang dapat merusak/ retak
dinding bangunan sekitar proyek.
 Pengoperasian alat sederhana.
 Memenuhi syarat teknik dan spesifikasi
bangunan.
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Dia 200 mm.
Dia 300 mm.
Dia 400 mm
Dia 600 mm
Dia 800 mm.
Dia 1000 mm
Dia 1200 mm
Dia 1500 mm
Dia 2500 mm, etc
Jenis mata bor yang di digunakan ada beberapa
macam sesuai dengan kondisi tanah yang akan di bor
antara lain :
Mata bor cross bit/ palang untuk segala jenis tanah.
Mata bor coring yang terbuat dari pipa sesuai
dengan diameter lubang dengan di beri batu widya/
mata intan pada ujungnya untuk tanah cadas
/cemented
 Mata bor ulir untuk tanah berkerikil atau berpasir.
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FHWA-NHI-10-016 4 - General Construction Methods
Drilled Shafts Manual 4-13 May 2010
FHWA-NHI-10-016 4 - General Construction Methods
Drilled Shafts Manual 4-13 May 2010
FHWA-NHI-10-016 4 - General Construction Methods
Drilled Shafts Manual 4-13 May 2010
FHWA-NHI-10-016 4 - General Construction Methods
Drilled Shafts Manual 4-13 May 2010
FHWA-NHI-10-016 4 - General Construction Methods
Drilled Shafts Manual 4-13 May 2010
FHWA-NHI-10-016 4 - General Construction Methods
Drilled Shafts Manual 4-13 May 2010
FHWA-NHI-10-016 4 - General Construction Methods
Drilled Shafts Manual 4-13 May 2010
FHWA-NHI-10-016 4 - General Construction Methods
Drilled Shafts Manual 4-13 May 2010
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Setting alat di titik pertama dan pembuatan bak sirkulasi.
Setelah hal tersebut sudah siap maka pengeboran di lakukan dengan rotary drilling
dynamo 20 PK, Pipa bor 3 meteran dia 2,5 inchi dan mata bor sesuai besar lubang yang
di inginkan.
Proses pengeboran di lakukan dengan memasukkan air dari bak sirkulasi yang di
pompa dengan menggunakan pompa sedot 3 inchi ke dalam watersifel yang di alirkan
ke dalam pipa bor 2,5 “ kemudian air akan ke luar pada ujung mata bor, air di gunakan
untuk mempermudah proses pengeboran sebagai pelunak tanah.
Bila lapisan tanah yang di bor adalah pasir , maka air di ganti dengan cairan bentonite.
Setelah lubang di bor sesuai dengan design atau mencapai tanah keras maka lubang
bor di bersihkan dari lumpur pekat atau gumpalan – gumpalan tanah dengan
menggunakan tabung pembersih.
Setelah lubang bersih maka besi tulangan dapat di masukkan ke dalam lubang dengan
hati -hati dan di beri cetakan semen pada setiap sisi tulangan untuk menjaga posisi
tulangan tidak bersentuhan pada dinding tanah.
Kemudian proses pengecoran beton slump 16 – 18 cm ( sesuai dengan prosedur
pengecoran bored pile) dapat di lakukan dengan terlebih dahulu memasukkan pipa
tremi.
FHWA-NHI-10-016 4 - General Construction Methods
Drilled Shafts Manual 4-13 May 2010
 The
dry method (Metode kering)
 The casing method (Metode casing)
 The wet method (Metode basah)
FHWA-NHI-10-016 4 - General Construction Methods
Drilled Shafts Manual 4-13 May 2010
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Dry hole construction represents the most favorable conditions for
economical use of drilled shafts.
The dry method is applicable to soil and rock that is above the water table
and that will not cave or slump when the hole is drilled to its full depth
during the period required for installation of the drilled shaft.
A homogeneous, stiff clay can often be drilled in this manner, and
sometimes homogeneous stiff clay can be drilled to moderate depths (up
to 50 ft) using the dry method regardless of the long term groundwater
levels because of the extremely low hydraulic conductivity of the soil.
The dry method can be employed in some instances with sands above the
water table if the sands contain some cementation or cohesive material,
or if they will stand for a period of time because of apparent cohesion.
This behavior generally cannot be predicted unless there is prior
experience with the specific formation being excavated or full-sized test
excavations have been made during site characterization.
FHWA-NHI-10-016 4 - General Construction Methods
Drilled Shafts Manual 4-13 May 2010
The construction process with a dry hole :
a) The shaft is excavated using augers which will likely have teeth to break
up the soil.
b) The base is cleaned using a bucket or flat bottom tool to remove loose
debris and possibly any small amount of water.
c) In most projects, a full length reinforcing cage is placed.
d) The concrete is placed using a drop chute or centering device.
FHWA-NHI-10-016 4 - General Construction Methods
Drilled Shafts Manual 4-13 May 2010
FHWA-NHI-10-016 4 - General Construction Methods
Drilled Shafts Manual 4-13 May 2010
Pelaksanaan pengeboran
pada lokasi pasir kering
tersementasi.
Peletakan tulangan yang dilapisi “Kaki” ke dalam
lubang bor
FHWA-NHI-10-016 4 - General Construction Methods
Drilled Shafts Manual 4-13 May 2010
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The casing method is applicable to sites where soil conditions are
such that caving or excessive soil or rock deformation can occur
when a shaft is excavated.
Casing can also be used to extend the shaft excavation through
water or permeable strata to reach a dry, stable formation.
Unless the bearing formation into which the casing is sealed is
stable and dry, it will not be possible to use the casing method
alone without the addition of drilling fluid or water.
Installation of casing is generally accomplished in one of three ways :
a)
1st Method : Excavate an oversized hole using the dry method, then
place the casing into the hole. This method is suitable only for
construction in soils that are generally dry or have slow seepage and
that will remain stable for the period of time required to advance the
hole to the more stable bearing stratum.
b)
2nd Method : Excavate an oversized hole through the shallow permeable
strata using a drilling fluid, then place and advance the casing into the
bearing stratum. After the casing is sealed into the underlying more
stable stratum, the drilling fluid can be removed from inside the casing
and the hole advanced to the final tip elevation in the dry.
c)
3rd Method : Advance the casing through the shallow permeable strata
and into the bearing formation ahead of the shaft excavation, and then
excavate within the casing in the dry. With this approach, casing may be
driven using impact or vibratory hammers or using a casing oscillator
or rotator with sufficient torque and downward force to advance the
casing through the soil ahead of the excavation. Even larger upward
force may be required to pull the casing during concrete placement.
FHWA-NHI-10-016 4 - General Construction Methods
Drilled Shafts Manual 4-13 May 2010
FHWA-NHI-10-016 4 - General Construction Methods
Drilled Shafts Manual 4-13 May 2010
Pemasangan casing pada kondisi tanah kering/bagus dengan
Vibro hammer dan twisting bar
FHWA-NHI-10-016 4 - General Construction Methods
Drilled Shafts Manual 4-13 May 2010
Sebuah Oscillator untuk mendorong casing ke dalam lapisan tanah
FHWA-NHI-10-016 4 - General Construction Methods
Drilled Shafts Manual 4-13 May 2010
FHWA-NHI-10-016 4 - General Construction Methods
Drilled Shafts Manual 4-13 May 2010
FHWA-NHI-10-016 4 - General Construction Methods
Drilled Shafts Manual 4-13 May 2010
Pipa Tremie
Casing
Muka Air Tanah
hw
? w. hw
hb
? b . hb
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Jika misalkan hw pada kedalaman -15 m,
Dasar Bore adalah - 45 meter
Maka pipa Tremie harus :
 1/10 * (45-15) m = 3 meter
 Jika dasar bore 45 meter, maka pipa tremie harus pada
kedalaman 42 meter ( minimal)
SF = hb/hw = 1/10
hb = 1/10 hw
Jadi ϒb. hb > ϒw. hw
FHWA-NHI-10-016 4 - General Construction Methods
Drilled Shafts Manual 4-13 May 2010
FHWA-NHI-10-016 4 - General Construction Methods
Drilled Shafts Manual 4-13 May 2010
FHWA-NHI-10-016 4 - General Construction Methods
Drilled Shafts Manual 4-13 May 2010
FHWA-NHI-10-016 4 - General Construction Methods
Drilled Shafts Manual 4-13 May 2010
FHWA-NHI-10-016 4 - General Construction Methods
Drilled Shafts Manual 4-13 May 2010
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When soil conditions do not permit dewatering of the shaft excavation, the excavation
and concrete placement operations must be completed “in the wet”. With this method,
the hole is kept filled with afluid during the entire operation of drilling the hole and
placing the reinforcing and concrete. The drilling fluid may consist of water if the hole is
stable against collapse, or a prepared slurry designed to maintain stability of the hole.
Several circumstances in which construction in the wet would be used are described below :
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The shaft is founded in a sand or permeable stratum which will collapse or become
unstable during excavation. A drilling slurry is required to maintain the stability of the
hole and prevent inflow of groundwater.
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The shaft is founded in a stable formation, but extends through caving or water-bearing
soils of such depth and thickness that the required casing would be very long and
difficult to handle. A drilling slurry is required to maintain the stability of the hole and
prevent inflow of groundwater.
A full length casing is driven in advance of the excavation, but the soil or rock conditions
at the base are permeable and do not permit dewatering. Because the full length casing
provides a stable hole, plain water can often be used instead of slurry.
The hole is cased to a stratum of rock which is stable, but groundwater inflow is greater
than 12 inches per hour. In this case, the hole is kept filled with water to prevent inflow
during concrete placement.
FHWA-NHI-10-016 4 - General Construction Methods
Drilled Shafts Manual 4-13 May 2010
FHWA-NHI-10-016 4 - General Construction Methods
Drilled Shafts Manual 4-13 May 2010
Gambar 9. Proses Pelaksanaan bore pile dengan metode basah
FHWA-NHI-10-016 4 - General Construction Methods
Drilled Shafts Manual 4-13 May 2010
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When the pore sizes in the formation being excavated are large (as in gravelly soils
or poorly graded coarse sands) the filter cake may be replaced by a deep zone of
clay platelet deposition within the pores that may or may not be effective in
producing a stable borehole.
FHWA-NHI-10-016 4 - General Construction Methods
Drilled Shafts Manual 4-13 May 2010
FHWA-NHI-10-016 4 - General Construction Methods
Drilled Shafts Manual 4-13 May 2010
FHWA-NHI-10-016 4 - General Construction Methods
Drilled Shafts Manual 4-13 May 2010
FHWA-NHI-10-016 4 - General Construction Methods
Drilled Shafts Manual 4-13 May 2010
FHWA-NHI-10-016 4 - General Construction Methods
Drilled Shafts Manual 4-13 May 2010
FHWA-NHI-10-016 4 - General Construction Methods
Drilled Shafts Manual 4-13 May 2010
FHWA-NHI-10-016 4 - General Construction Methods
Drilled Shafts Manual 4-13 May 2010
FHWA-NHI-10-016 4 - General Construction Methods
Drilled Shafts Manual 4-13 May 2010
FHWA-NHI-10-016 4 - General Construction Methods
Drilled Shafts Manual 4-13 May 2010
FHWA-NHI-10-016 4 - General Construction Methods
Drilled Shafts Manual 4-13 May 2010