ANALISIS STABILITAS DAN REMBESAN AIR PADA DINDING PENAHAN TANAH PROYEK INTAKE KECAMATAN SEPAKU KABUPATEN PENAJAM PASER UTARA

ABSTRACK
This project is located on the Sepaku River with an original width of 10-15
m so that to meet the required amount of water, it is necessary to widen the river
along the upstream and downstream. Then a retaining wall is needed as a
structure that can withstand lateral earth pressure. The use of this retaining wall is analyzed for stability against shear, overturning and failure of the carrying capacity to determine the factor of safety
against the soil embankment load and the load due to river water under low tide, normal and high tide conditions, as well as to determine the safety factor against
the danger of water seepage. cause piping zones using the Hazra and Terzagi
methods and the calculations are done manually. From the results of the analysis it is known that the stability of the
retaining wall with normal river water conditions is 3.8 m, tide conditions are 4.5
m and low tide conditions when the water is empty, for shear stability it is
obtained 1.5; 1.4: and 1.9 under normal and low tide conditions can be declared
safe because the numbers obtained are ≥1.5 but not safe at high tide conditions, the stability of the roll the number obtained is 7.58; 7.47 and 7.83 are declared
safe because the values obtained are ≥ 1.5, the stability against collapse of the
soil carrying capacity is 13.3; 16.72 and 8.8 are declared safe because the scores
obtained are ≥3. While the results of the hazard analysis of water seepage using
the hazra method obtained 13.3; 16.72 and 8.8, and using the divided method the
numbers obtained were 9.474; 8.197 and 0. In the seepage hazard analysis it can
be declared safe because the numbers obtained are ≥ 4, but at low tide it is
declared unsafe. So the stability of the retaining wall against overturning and soil
bearing capacity in three water level conditions can be declared safe because it
meets the requirements for the planned safety factor, but in the analysis of the
calculation of the safety factor against the danger of water seepage it is stated
that it is not safe because it does not meet the safety factor that has been planned. Keywords: Retaining wall stability, water seepage, flownet
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ABSTRAK
Proyek ini berada di Sungai Sepaku dengan lebar aslinya 10-15 m sehingga
untuk memenuhi kebutuhan jumlah air maka diperlukan pelebaran sungai
sepanjang bagian hulu dan hilir. Maka dibutuhkan dinding penahan tanah sebagai
struktur yangk menahan tekanan tanah lateral. Penggunaan dinding penahan tanah ini dilakukan analisis stabilitas terhadap
geser, guling dan keruntuhan daya dukung untuk mengetahui angka faktor
keamanan terhadap beban tanah timbunan dan beban akibat air sungai dalam
kondisi air surut, normal dan kondisi pasang, serta untuk mengetahui angka
keamanan terhadap bahaya rembesan air yang mengeyababkan piping zone
dengan menggunakan metode Hazra dan Terzagi serta perhitungan dilakukan
secara manual. Dari hasil analisis diketahui angka stabilitas dinding penahan tanah dengan
kondisi muka air sungai normal 3,8 m, kondisi pasang 4,5 m dan kondisi surut
pada saat air kosong, untuk stabilitas geser diperoleh 1,5; 1,4: dan 1,9 dalam
kondisi normal dan surut dapat dinyatakan aman karena angka yang diperoleh
≥1,5 namun tidak aman pada konsidi air pasang, stabilitas guling angka yang
diperoleh 7,58; 7,47 dan 7,83 dinyatakan aman karena angka yang diperoleh ≥ 1,5, stabilitas terhadap keruntuhan kapasitas dukung tanah angka yang diperoleh 13,3;
16,72 dan 8,8 dinyatakan aman karena angka yang diperoleh ≥3. Sementara hasil
dari analisis bahaya rembesan air dengan menggunakan metode hazra diperoleh
13,3;16,72 dan 8,8, serta dengan menggunakan metode terzagi angka yang
diperoleh yaitu 10,105; 8,533 dan 0. Pada analisis bahaya rembesan dapat
dinyatakan aman karena angka yang diperoleh ≥ 4, namun pada kondisi surut
dinyatakan tidak aman. Maka Stabilitas dinding penahan tanah terhadap geser
guling dan kapasitas dukung tanah dalam tiga konsisi muka air dapat dinyatakan
aman karena memenuhi syarat faktor keamanan yang direncanakan, namun dalam
analisis perhitungan angka keamanan terhadap bahaya rembesan air dinyatakan
tidak aman karena tidak memenuhi faktor keamanan yang telah direncanakan. Kata kunci: Stabilitas dinding penahan tanah, rembesan air, flown