Procedure and Challenges in ground investugation.pptx

The Procedure and Challenges of Ground Investigation in Timor-Leste

1. Ground Investigation: Procedure and Challenges 14/02/25

2. Agenda Introduction Importance of Ground Investigation Key Steps of Ground Investigation Challenges

3. Introduction Ground investigation plays a fundamental role in ensuring the safety, stability, and longevity of any construction project, including roads, bridges, buildings, or other infrastructure. However, this essential step is often overlooked, leading to serious engineering and financial consequences. In Timor-Leste, the diverse terrain, varying soil conditions, and natural hazards such as landslides and erosion, presents unique geotechnical challenges. Without proper ground investigation, projects face structural failures, cost overruns, and safety risks. Unfortunately, the awareness and enforcement of geotechnical studies remain limited, leading to inadequately designed infrastructure that may fails prematurely.

4. Importance of Ground Investigation Assessing ground Conditions - Identifies soil type, strength and groundwater condition Ensure Foundation suitability - Determine bearing capacity and recommends suitable foundation type Identifying Geohazard - Detect problematic soil such as expansive clay, loose sand and soft peat Minimizing construction risk – Ensure the stability of foundation, slopes and embankment Optimizing design and costs – provide accurate data for efficient structure design, minimize overdesign and costly remedial measure Selecting Suitable Construction Methods and Materials - Help determining suitable method and material for construction Evaluating Environmental conditions - Assesses soil and groundwater contamination

5. 1. Desk Study & Site Reconnaissance (Preliminary Investigation) Purpose: Gather existing information and conduct an initial assessment of the site. Activities: Desk Study: Review geological maps, topographic maps, and satellite imagery. Check historical land use, past construction records, and geotechnical reports. Assess environmental factors, groundwater conditions, and known hazards. Site Reconnaissance (Walkover Survey): Inspect the site for visible geological and hydrological features. Identify signs of instability (e.g., cracks, slope failures, groundwater seepage). Locate existing structures, utilities, and access constraints.

6. 2. Ground Investigation (Field Exploration & Sampling) Purpose: Collect soil, rock, and groundwater data through in-situ tests and borehole drilling. Activities: Drilling & Sampling: Boreholes, trial pits, and test pits to assess soil stratigraphy. Collection of undisturbed and disturbed samples for lab testing. Groundwater monitoring using piezometers. In-Situ Testing: Standard Penetration Test (SPT) – Soil strength and density. Cone Penetration Test (CPT) – Soil classification and bearing capacity. Vane Shear Test (VST) – Shear strength of soft clays. Pressuremeter Test (PMT) – Soil deformability. Permeability Tests – Measure hydraulic conductivity.

7. Boreholes

8. U-50 OR UNDISTURBED SAMPLE DISTURBED SAMPLE Type of soil Sampling

9. 3. Laboratory Testing & Reporting Purpose: Analyze soil and rock properties to provide geotechnical design recommendations. Activities: Laboratory Testing: Index Properties: Moisture content, Atterberg limits, grain size distribution. Shear Strength Tests: Direct shear, triaxial, unconfined compressive strength. Consolidation Tests: Oedometer tests for settlement analysis. Chemical Tests: Soil aggressiveness to concrete and steel. Geotechnical Report Preparation: Summarize site conditions, soil profiles, and test results. Provide geotechnical parameters for foundation design, slope stability, and earthworks. Recommend suitable construction techniques and potential risks.

10. Grain Size Analysis (Coarse Grain soil Classification)

11. Atterberg Limit - Determine the plasticity of soil (Fine grain soil classification)

12. Challenges of Ground Investigation (Timor-Leste) Geological Complexity - Unexpected ground condition Site Accessible Issues - Remote locations, traffic congestion, and urban restriction Limited Resources and Expertise - Human error and data accuracy Climate and Weather Conditions – Impact on site investigation and equipment use Data and Historical Information – Limited records for accurate predictions Environmental and Cultural Sensitivities – Regulations may restrict investigation in protected areas and community concerns delay or affect investigations Groundwater Safety and environmental assessment - High groundwater levels, contamination risks, and the need for dewatering solutions. Logistic and equipment constrains – Transporting materials and machinery to remote or difficult location and limited availability of advance tools can impact investigation quality.

13. Thank you