Understanding subsurface conditions is the key to any successful construction project including new construction, excavation, and drilling. The consideration and understanding of the subsurface geology and, in some cases, hydrogeology is paramount to minimizing risks prior to starting and completing a successful project. A necessary first step in this process is the gathering and research of existing geological data on a project site and or area. This information can include such things as published reports and studies, geotechnical and geological assessments, soil reports, driller’s logs, and geophysical logs. By using this available knowledge, surface geophysical techniques can then be applied to a site to maximize and fine tune proposed structure locations and minimize risks related to geohazards. Surface geophysical methods can also be used to obtain local geological information thereby providing an overall better picture of the subsurface.
Texas is one of the fastest growing populations in the United States and is expected to grow by 50 to 100% over the next 30 years. Because of this population growth new infrastructure is being built in undeveloped areas and old infrastructure is being stressed. Both scenarios provide a potential for the presence and effects of unseen geohazards. Geophysical surveys have been used to support numerous pre-engineering investigations for these scenarios. Applications include: pre construction investigation for voids and karst features along roadways and other infrastructure; assessment of earthen dams and levees for fractures, faults, and seepage; characterization for pre-tunnel excavation; the collection of seismic velocities for the calculation of dynamic moduli to assist in foundation design, and many others. This presentation focuses on the use of available geophysical tools that can help reduce risk and increase success on engineering projects.