What is Geotechnical Engineering
Geotechnical Engineering is a branch of Civil Engineering. Geotechnical engineering uses the principles of soil mechanics and rock mechanics to investigate the subsurface condition, which helps in the design of the foundation for structures.
Geotechnical Engineers provide various services
Geotechnical Investigation involves the process of drilling boreholes, taking soil samples, testing them in the laboratory, analyze the test report, and recommend a suitable foundation. The depth and number of holes depend on the area of the site and type of structure that will be built. Based on the soil report, a geotechnical engineer may recommend the improvement of the soil before any foundation can be built. The Geotechnical engineer also recommends the type of foundation, whether a deep foundation or shallow foundation is required. The foundation can be strip footing or pile foundation. The depth and type of pile are recommended based on the soil characteristic. Investigation of groundwater and investigation of rock, if encountered, also forms part of the geotechnical investigation report.
Pile Load Test:
Geotechnical Engineers also involve in load tests of piles. The load testing of piles forms a fundamental part of foundation design for larger projects. The result of the pile load test is used to determine the ultimate load-carrying capacity of the pile and measure the load settlements to verify the design assumptions. The load test provides information regarding axial geotechnical load capacity in uplift and in compression. The lateral geotechnical load capacity. The performance of the pile under lateral and axial load. The contractibility of piles. A different load test is needed to provide the above information. There is a different type of load tests such as static load test or dynamic load test.
Geotechnical Engineers recommend the type of material based on the soil condition to improve the strength of soil or improve the drainage condition. Geotextile materials are used to improve the drainage and reinforces the soil. Geogrid is used to improve the strength of the soil.
Related Read: What Do Geotechnical Engineering Consultants Do?
Inspection of Deep Foundation:
Geotechnical Engineers carry out field review to ascertain that the subsurface conditions are in conformance with the design and that construction is carried out as per the design and follows good engineering practices. The inspection is carried out on a continuous basis during the construction of all deep foundation units. During the inspection, Geotechnical Engineers identify any faulty construction procedure, interpret pile driving data, and evaluate soil conditions in bored piles. The Geotechnical engineers, before the construction start, review the soil investigation report, foundation drawings, and any other special design features such as the hammer datasheet. The Geotechnical Engineers check the number and location to ensure that it as per the design drawing. They check the alignment of the pile against the design alignment and ensure that they are within the permissible deviations. The curvature of the pile is also checked. For a concrete pile, a centre tube is cast to provide access for inspection.
Geotechnical engineering company provides construction support. Like proof roll test, an inspection of foundation excavation before the concrete pour. In situ tests like soil compaction test, concrete sampling for cube test, slump test. They also provide Asphalt core sampling for testing in the laboratory. Some Geotechnical companies also carry out all the material testing of soil, concrete, and asphalt in their laboratory, or they can outsource to a third-party laboratory. All test result irrespective of where they are conducted are analyzed by geotechnical engineers, and appropriate recommendation is provided from time to time during the course of construction. Although the geotechnical investigation is carried out to know the subsurface condition, sometimes, unexpected site conditions may arise. In such a case, the Geotechnical Engineers reviews the site condition and appropriate control measure is suggested.
The above geotechnical services provided by a geotechnical engineer in civil engineering are immense. From preconstruction to the completion of construction projects, modern-day civil engineering marvel would not have been possible.
Reference: Canadian Foundation Engineering Manual.