The Analysis Slope Stability Reservoir Keuliling with Finite Element Methods

Abstract

Abstrak. Keruntuhan timbunan tanggul dapat menyebabkan tidak stabilnya lereng baik dihulu maupun di hilir. Keruntuhan permukaan lereng terjadi karena aliran air di dalam tubuh bendung dan tanah pondasi. Kondisi kritis terjadi di lereng hulu waduk pada saat selesai konstruksi dan penurunan muka air tiba-tiba. Tahapan kritis pada hilir bendung pada saat selesai konstruksi dan terjadi rembesan ketika ketinggian air waduk penuh. Penelitian ini difakuskan pada analisa stabilitas lereng Waduk Keuliling di Kabupaten Aceh Besar. Analisa ini menggunakan elemen segitiga dengan 15 titik nodal metoda elemen hingga dan bantuan program Plaxis 7.1.1. Angka keamanan yang dihasilkan dalam analisa ini adalah 2,3 - 2,5 pada sta 0+500 sampai sta 0+600. Pada kondisi jangka panjang selesai konstruksi dihasilkan angka keamanan sebesar 2,78 - 2,88 dan kondisi penurunan muka air tiba-tiba dihasilkan angka keamanan 2,2 - 2,4.

Abstract. Failure of an embankment dam can be caused by instability of either the upstream or downstream slopes. The failure surface may lie within the embankment or may pass through the embankment and the foundation soil. The critical stages in an upstream slope are at the end of construction and during rapid drawdown. The critical stages for the downstream slope are at the end of construction and during steady seepage when the reservoir is full. This paper is focused on analyzing the slope stability of dam Waduk Keuliling located in Kabupaten Aceh Besar. All of the analyses were performed based on finite element method with the help of a computer program Plaxis 7.1.1. The triangle element with 15 nodes were used in the analyses. The result of the slope stability analysis show that the safety factor at the end of construction of sta 0+500 to sta 0+600 is2.3- 2.5.The safety factor obtain of the long construction is 2.78- 2.88 and the dam condition during rapid drawdown is 2.2 "? 2.4.