CD Tesis

Analisis Balik Perbaikan Tanah Menggunakan Metode Vacuum Consolidation Pada Proyek Perluasan Runway Bandara Di Kota Jambi

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Sultan Thaha Airport is currently undergoing additional runway work. The
runway addition work is carried out for 390 m plus a stopway length of 60 m and
a RESA length of 90 m. The airport soil condition along the location of the
addition of the sultan thaha runway according to the planning data is classified as
soft to very stiff clay at every depth, the ground water level is at a depth of -3 m, it
is necessary to improve the soil and after conducting a soil investigation in the
early stages of implementation there is a face position groundwater has increased
to a depth of -1 m, requiring soil improvement. To overcome this problem, one
alternative is soil improvement such as the use of pile foundations used in
Indonesia. Another alternative is the use of vertical drain (PVD) to speed up
consolidation settlement time so that shear strength increases. As is generally
known, the use of PVD Surcharge must be accompanied by preloading in order to
cause the effect of voltage differences in the soil and at the ground surface so that
air can flow easily which is then accelerated through the Vertical Drain lines that
have been planted. However, the airport's high stockpile causes operations to be
disrupted due to the stockpile (preload). Combination of PVD with vacuum is a
method that can be used. The Vacuum Consolidation method is a soil
improvement method by attaching a pump to the line to be connected to the PVD
which applies vacuum suction to the expanding soil mass, reducing the
atmospheric pressure within it, so that by reducing the air pressure in the soil the
effective stress increases without changing the total stress. This method has begun
to be widely used in Indonesia, although it is still in relatively small quantities so
that it becomes an interesting material to study. The purpose of this study is to
determine the magnitude of subsidence without soil improvement with soil
improvement using PVD alone, PVD with vacuum and PVD with vacuum from
back analysis to provide a suitable final settlement from field geotechnical
instrumentation by correlating the laboratory Cc (compressibility coefficient)
value and Ch value. (radial coefficient) of plate calculations using the Asaoka
method. Due to the magnitude of the decrease which is quite far from the results
of calculations in the field. As for what is used to determine the calculation of
settlement, degree of consolidation, air pressure can be analyzed with field data
Ch from pore air pressure is also needed for comparisons between the radial
coefficients of Settlement Plate and Piezometer. Monitoring Settlement Plate aims
to determine the vertical settlement of the soil due to embankment loads. This
instrumentation is installed after the work platform is ready at predetermined
locations, the design in the zone 4 area of the runway extension is 3 points.
Vibrating Wire Piezometer monitoring aims to measure changes in pore water
pressure (pwp) or in addition to stress on the soil. Instrumentation is placed at the
depth unde consideration, fine sand and bentonite are required as filters. Pore
water pressure readings are carried out periodically according to the needs and
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interpretation of the engineer, which amounts to 2 points. Activities to measure
the groundwater level from outside the vacuum area, namely the installation of 2
points of Water Stand Pipe.
The results showed that from the data on the vertical decrease in
measurements on the Settlement Plate due to the vacuum process in the period 27
October 2018 – 31 December 2018 was a decrease which was dominated by the
initial phase of the vacuum the decline had reached a value of 15.3 - 20.2 cm. For
measurement data on the pressure of the Vibrating Wire Piezometer, the
estimated value is 71.8 - 72.5 kPa. Activities in measuring the groundwater level
can use a water stand pipe, namely using a pipe installed on the outer side of the
vacuum, which shows that there is no relative influence of the groundwater level
outside the vacuum area. To keep the vacuum pressure stable. To have reached a
degree of consolidation of 90% without soil improvement, the magnitude of the
decrease is 49.35 cm with a time of 7300 days or 20 years. To have reached a
degree of consolidation of 90% with PVD using a square pattern with a distance
of 1.3 m in zone 4, the magnitude of the decrease is 51.53 cm with a time of 116.8
days. To have reached a degree of consolidation of 90% with PVD with a vacuum
using a square pattern with a distance of 1.3 m in zone 4, the magnitude of the
decrease is 47.84 cm with a time of 116.8 days. Meanwhile, to have reached a
degree of consolidation of 90% with PVD with a vacuum with Back Analysis using
a square pattern with a distance of 1.3 m in zone 4, the magnitude of the decrease
is 15.02 cm with a time of 116.8 days. From the results of the comparison above,
which is close to the field is to use the correlation analysis behind the values of Cc
and Ch. The results of this calculation use the theoretical calculation of
Terzaghi's one-dimensional consolidation. The calculation for the new soil
parameter in the reverse analysis of Ch zone four on the Settlement Plate is 17.4
cm with the Asaoka method from the instrumentation in the field, it is obtained
almost the same value, namely the decrease that occurs is 17.9 cm. The value of
Ch Piezometer on the 26th day is 63.50m²/year. From the calculation results, it is
shown that the consolidation decrease that occurs with a vacuum pressure of 80
kPa using a square installation pattern with a distance of 1.3 m gives significant
results from the decrease in the field as well as theoretically. However, if you
want a larger reduction, the installation distance of 1 m should be superior.
Comparison of the results of theoretical calculations with monitoring results will
show the success of the vacuum preloading method as an alternative method of
accelerating consolidation in clay soils.
Key words : Back Analysis, Asaoka Method, Soft Soil Improvement, Actual
Derivation and Vacuum Consolidation.

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Ketersediaan

Informasi Detail

Judul Seri

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No. Panggil

1710246612

Penerbit

Pekanbaru : Universitas Riau – Pascasarjana – Tesis Teknik Sipil., 2021

Deskripsi Fisik

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Bahasa

Indonesia

ISBN/ISSN

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Klasifikasi

1710246612

Tipe Isi

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Tipe Media

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Tipe Pembawa

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Edisi

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Subjek

TEKNIK SIPIL

Info Detail Spesifik

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Pernyataan Tanggungjawab

FATAH

Versi lain/terkait

Lampiran Berkas

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