An Analytical Solution for Non-Darcian Flow on a Constant Head Packer Test in the Interlayer Staggered Zone

Groundwater flow in an aquifer has frequently been found to be non-Darcian by performing in situ tests. A novel analytic model is proposed in this study for describing the unsteady non-Darcian flow in a confined aquifer by taking advantage of the observed flow rate and injection pressure during the constant head packer test. A linearization approximation of the Izbash equation is used to approximate the nonlinear term in the governing equation. This analytic model is applied to describe the non-Darcian flow in the interlayer staggered zone at the Baihetan hydropower station, China. The test results inversed by the genetic algorithm show that non-Darcian flow happened during the test under the injection pressure 0.3 MPa with the power index n is 1.278, non-Darcian hydraulic conductivity k 1 is 1.613 × 10 − 5 cm/s and the specific storage S s is 9.757 × 10 − 5 m-1, respectively. The sensitivity analysis indicated that when the power index n or the specific storage S s is larger, and the hydraulic head will increase more slowly and needs longer to stabilize, but the non-Darcian hydraulic conductivity k 1 shows the opposite trend. Moreover, the hydraulic head is more sensitive to the power index n compared to other parameters at late times. The findings of this study reveal the non-Darcian flow during the constant head packer test and provide a simple and fast way to estimate parameters for more accurate seepage field simulation.

Estimasi Konduktivitas Hidraulik Rekahan Batuan Menggunakan ANFIS : Perbandingan dengan HC-System

Intensitas rekahan batuan yang tinggi pada proyek geoteknik seperti terowongan, lereng, dan pembangunan bendungan sangat dipengaruhi oleh kehadiran airtanah. Aliran airtanah media rekahan lebih sulit diprediksi daripada aliran media berpori. Konduktivitas pada media rekahan lebih umum diukur dengan packer test. Karena adanya batasan finansial dan waktu, pengukuran dapat digantikan menggunakan korelasi dengan parameter atau indeks yang lebih mudah didapatkan untuk mengestimasi dan memodelkan nilai konduktivitas yang sebenarnya. Salah satu sistem korelasi indeks yang umum yang digunakan yaitu HC-system. Sistem tersebut terdiri dari 4 indeks yaitu RQD, kedalaman, isian, dan permeabilitas pori batuan. Nilai HC-system berkorelasi sebesar R2 = 0,85 dengan hasil packer test dari metode regresi. Prediksi konduktivitas hidraulik dapat ditingkatkan dengan metode ANFIS (Adaptive Neuro-Fuzzy Inference System). Metode alternatif ini dapat menghasilkan korelasi keempat indeks dengan hasil packer test sebesar R2 = 0.96

Studi Literatur Pendugaan Nilai Konduktivitas Hidraulik Dengan Menggunakan Data Uji Hidraulik Lapangan Dan Data Loging Geoteknik

Konduktivitas hidraulik merupakan parameter yang sangat penting dalam pemodelan aliran airtanah. Parameter tersebut dapat diambil melalui pengujian packer test dan slug test . Mahalnya operasional pelaksanaan pengujian tersebut, memberikan dampak minimnya data kondutivitas hidraulik di lapangan. Konduktivitas hidraulik pada batuan yang terkekarkan memiliki kompleksitas (derajad heterogenitas dan anisotropi) yang lebih tinggi dibandingkan dengan konduktivitas hidraulik pada batuan sedimen. Untuk mengatasi minimnya data konduktivitas hidraulik, dalam studi literature ini akan dilakukan cara prediksi nilai konduktivitas hidraulik dengan menggunakan pendekatan metode HC-System. HC-System merupakan metode empirik yang melibatkan data-data geoteknik menduga nilai konduktivitas hidraulik di daerah yang tidak ada data pengukuran (terbatas pada titik pengukuran geoteknik). Data geoteknik tersebut terdiri dari Rock Quality Designation (RQD), Lithology Permeability Index (LPI), Depth Index (DI), and Gouge Content Index

Modeling Spatial Distribution of 3D Isotropic Hydraulic Conductivity Based on HC-System for Fractured Groundwater Flow Media using Neural Network Case Study Grasberg Open Pit of PTFI

Hydraulic conductivity property is very important for groundwater flow modeling. It can be gathered through packer test and slug test. The high cost of the operational implementation of these tests lead to the limited availability of observational-based distribution of hydraulic conductivity data. Highly fractured rocks in Grasberg open pit mining and surrounding of PT Freeport Indonesia (PTFI) result in fractured-groundwater-flow media. It is related to the complex geological structure and lithological condition. Groundwater modeling needs 3D distribution data such hydraulic conductivity (K). On previous research, hydraulic conductivity is distributed homogenyneously at each layer model. In this paper, under limited observational hydraulic conductivity, isotropic hydraulic conductivity will be modeled based on the HC-System approach and will be three-dimensionally distributed using Artificial Neural Network (ANN). HC-System approach will be developed according to the packer test and slug test measurement using geotechnical data from drilling such as Rock Quality Designation (RQD), Lithology Permeability Index (LPI), Depth Index (DI), and Gouge Content Index. HC-System approach will be resulted in isotropic distribution of hydraulic conductivity. It is then checked at some points by the packer tests and slug tests observational data. It is further very beneficial for modeling of groundwater distribution flow with the heterogeny hydraulic conductivity.

The Treatment Technology of Banbidian Goaf in Qinhuangdao

The issues induced by underground mining are worldwide difficulties because the mined-out area is undesirable due to its implicity, complexity and large deformation. This paper describes the harmfulness of golf in highway construction based on the general failure characteristics of overlying rock masses. Grouting method was employed to improve the Banbidian goaf. Verification of the reinforcement effect was carried out using packer test and core extraction. The results show that this technique has achieved desired effects and hence could be referenced by other fellows.