ANALISIS TEGANGAN-REGANGAN- WAKTU PADA KONSOLIDASI BIOT DENGAN MENGGUNAKANPEMODELAN TANAH " DRUCKER-PRAGER "

(Studi Kasus Pembangunan Bendung Sei Rempang di Pulau Batam)

T 624.151 362 ISK

ABSTRAK

Proses terdisipasinya excess pore water pressure darimussel tanah disebut proses konsolidasi. Teori konsolidasiTerzaghi (1925) menganggap nilai koeffisien konsolidasi konstandan pengaliran excess pore water pressure hanya ke arah vertikal.Blot (1941) mengembangkannya dengan mengasumsikanpengaliran dan regangan yang terjadi ke tiga arah((multydimensional case), tegangan vertikal efektif dan excess pore waterpressure merupakan fungsi transient. Penyelesaiannya dilakukandengan mengcouplekan hubungan pertambahan tegangan-regangandan pengaliran pada media porous

Pada penelitian ini diturunkan rumusan konsolidasi Blotyang diimplimentasikan dalam program Plaxis, dire view kembaliteori model-model tanah, menghitung hubungan pertambahantegangan regangan dengan mengintegralkan matrik konstitutifpertambahan tegangan regangan model Drucker-Prager,menghitung besar penurunan secara analisis dan memprediksikanbesar penurunan berdasarkan data pengamatan lapangan denganmetoda Asaoka. Program Plaxis digunakan uniuk men.simulasikanpelaksanaan pembangunan benching Sei Rempang di pulau Batamdengan terlebih dahulu memverifikasi vertikal drain yangterpasang dilapangan setempat-setempat ke kondisi plane strain,dianalisa excess pore water pressure, penurunan vertikal,displacement horizontal, hubungan tegangan-regangan, teganganterhadap waktu, regangan terhadap waktu dengan menggunakanmodel Drucker-Prager dan hasilnya dibandingkannya dengananalitis dan pengamatan lapangan.

Hasil penelitian dengan model ini menunjukkan adanyakesesuaian respon program Plaxis dengan yang terukur di lapangandan analisis. Excess pore water pressure yang dibangkitkan daripengamatan lapangan pada hari ke-215, 24,53 Kpa, analitis 32,04kPa dan Plaxis 24,66 Kpa, derajat konsolidasi rata-rata yangdicapai hari ke 255 (pengkonsolidasi 40 hari), pengamatanlapangan 56,0 %, analitis 77,60 %.dan Plaxis 72, 36 %. TotalSettlement, pengamatan lapangan 0,80 m, analitis 0,78 7 m danPlaxis 0, 792 m, horizontal displacement lapangan 0,326 m, Plaxis0,24 m. Hasil model ini diperkirakan cukup realisis, untuk selanjutnya pada pekerjaan yang sama dapat digunakan simulasi denganmenggunakan model Drucker-Prager.

A B S T R A C T

The process of dissipation of excess pore water pressurefrom soil mass is called as process of consolidation. Theconsolidation theory by /erzaghi (1925) assumed that thecoefficient of consolidation is constant and the flowing of excesspore water pressure are only to vertical direction. Blot (1941)developed the theory of Terzaghi consolidation with assumptionthe flowing excess pore water pressure and strain are occurred inthree direction (multy dimensional case), effective vertical stressand excess pore water pressure is transient junction. On thesolution involves the couple process between the relationship ofthe increase of .stress-strain and the flowing through porous media.

The research can show Biot's consolidation formulawhich has been implemented in Plaxis program, reviewed basictheory of soil-modelling, to calculate the relationship between theincrease of stress-strain with integrated increase constitutif matrixstress strain Drucker-Prager model, to calculate settlement withanalysis and to predict settlement based on the data o f fieldobservation by Asaoka method. The using Plaxis program is tosimulate the implementation of Sei Rempang Dam construction inBatam island by verification the vertical drain first which has beeninstalled in the field from local conditions to plane straincondition, excess pore water pressure is analysed, verticaldisplacement, horizontal displacement, relationship stress strain,stress against time, strain against time, using Drucker-Pragermodel and the result is compared to the analysis and the fieldobservation.

The result of this research show that there are anadjustment from the Plaxis program respons against the valuewhich is measured in the field and analytical calculation. Excesspore water pressure that is generated on field observation on the215th day, 24,53 kPa, analytical 32,04 Kpa, Plaxis, 24,66 kPa,average degree of consolidation that has been obtained until the255'h (consolidation 40 days), on field 56,00 %, analytical 77,60 %and Plaxis 72,36 %. Total settelement, field 0,80 m, analytical 0,787 m and Plaxis 0,792 m, horizontal displacement, field 0,326 mand Plaxis 0,24 m. The result of this model is realistic enough ,futhermore, for the same kind of works should be used thesimulation of Drucker-Prager model.

i i