Evaluasi Penggantian Tanah dan Injeksi Grouting Semen Terhadap Penurunan Tanah

This paper discusses the process of original soil stabilization in Trans Sumatra Bakauheni-Terbanggi Besar Toll Road Project Package 2 Sidomulyo-Kotabaru. The soil replacement process was conducted at approximately 24 kilometres along the toll’s main road. The original soil bearing capacity analysis stage was by performing a Dynamic Cone Penetrometer (DCP) and Sondir test to analyze the deep of hard soil. A soil replacement was carried out to replace the original soil with soil that has appropriate specification. the piling up process was conducted in stages, which has Sandstone in such of the layer. The research done about the landfill sample was retaken and collected at 68 points. The stockpile soil samples collection was then followed by the analysis which was conducted in the laboratory to find the soil bearing capacity. There are 4 types of bearing capacity parameters analyzed, namely specific gravity, water content, aggregate analysis (Sieve Analysis), and consistency limit (Atterberg Limit). Referring to it, then there was the classification of soil types according to AASHTO M145 & Casagrande Soil Classification System. A point that has settlement after soil replacement is STA 52+000. So, there need to add soil stabilization, that is cement grout injection. Researchers analyzed the soil settlement by interpretation method. Results showed that soil replacement and cement grout injection could decrease a soil settlement by about 15.07 cm to become 0.93 cm.Penelitian ini membahas tentang proses stabilisasi tanah pada proyek Jalan Tol Trans Sumatera Bakauheni – Terbanggi Besar paket 2 Sidomulyo – Kotabaru. Pekerjaan penggantian (replacement) tanah dilakukan di sepanjang ±24 km (setempat) sepanjang jalan tol. Pada tahap analisa daya dukung tanah asli, dilakukan pengujian Dynamic Cone Penetrometer (DCP) dan Tes Sondir guna mengetahui kedalaman tanah keras. Kemudian dilakukan penggantian (replacement) tanah dengan material sesuai spesifikasi. Penimbunan material tanah dilakukan secara bertahap dengan dilakukan pengujian Sandcone di setiap layer. Kemudian dilakukan penelitian dengan pengambilan sample tanah timbunan pada 68 titik lokasi. Setelah dilakukan pengambilan sample, selanjutnya dilakukan analisa di laboratorium mengenai daya dukung pada sample tanah tersebut. Parameter daya dukung yang dianalisa sebanyak 4 jenis, yaitu berat jenis tanah (Specific Gravity), kadar air (Water Content), analisa agregat (Sieve Analysis), dan batas konsistensi (Atteberg Limit). Mengacu pada parameter tanah, dilakukan pengklasifikasian jenis tanah sesuai AASHTO M145 & Casagrande Soil Classification System. Terdapat lokasi yang mengalami penurunan pasca penggantian (replacement) tanah, yaitu STA 52+000. Sehingga perlu dilakukan tindakan stabilisasi tambahan yaitu injeksi grouting semen. Peneliti menganalisis penurunan (settlement) tanah menggunakan metode interpretasi, hasilnya menunjukkan bahwa pelaksanaan penggantian (replacement) tanah dan injeksi grouting semen dapat memperkecil angka penurunan (settlement) tanah dari sebesar 15,07 cm menjadi sebesar 0,93 cm