MEA-serviced geotechnical and civil engineering projects can be found in every corner of the United States. As one of the leading geotechnical engineering consultants for subsidence engineering in the nation, prospective and abandoned mines can be expertly evaluated by MEA. In addition to the geotechnical design and forensic work related to subsidence, MEA has diverse experience with complex geotechnical civil engineering difficulties.
Several examples of more recent projects that MEA has been consulted on can be seen below:
Introduction: A wall was designed to stabilize a slope for a homeowner in Illinois.
Description: Landslide occurred involving two residences. MEA performed a subsurface and groundwater investigation and laboratory testing to determine the cause and characteristics of the slide. The slide was also mapped and surveyed.
Outcome: MEA developed the plans and specifications for an MSE retaining wall which was approved by the City. The wall was successfully constructed.
Introduction: A department store was looking at a potential site for new development and asked MEA to perform a subsurface investigation.
Description: MEA performed a subsurface investigation of geologic/geotechnical conditions, soil and rock mechanics testing, and pavement and foundation design. The subsurface investigation consisted of drilling of SPT holes and augers, logging, surface electric resistivity, and lab testing. MEA also assessed subsidence and associated damage risks from karst and remediation alternatives. Designed and supervised compaction grouting of karst features.
Outcome: MEA prepared a full geotechnical report on our findings to assist the client in developing the site and successfully treated subsidence prone features.
Introduction: A regional airport was planning on constructing a new air traffic control tower and wanted MEA’s help with the foundation and pavement design, as well as underground mine issues.
Description: MEA performed a full subsurface investigation and soil/rock testing of the foundation conditions, which included pressuremeter testing. Provided foundation recommendations for the proposed air traffic control tower and base building as well as pavement recommendations. Also investigated underground mining conditions and provided subsidence and damage potential estimates for the site in addition to mine remediation measures.
Outcome: MEA prepared a full geotechnical report including foundation recommendations and a mine remediation plan.
Introduction: Client requested MEA provide emergency assistance on two construction sites which were experiencing landsliding events and had MSE wall designs which were incompatible with the existing site conditions. MEA investigated land slide instability and other site conditions and developed retaining structures and reinforced earth designs to stabilize the sliding conditions that were compatible with the site conditions.
Description: MEA performed subsurface investigation, surface mapping of slope conditions, and design analyses. This included slope and wall stability analyses. MEA provided client with plans and specs of reinforced earth and retaining wall designs.
Outcome: MEA prepared designs and plans and specification for construction to resolve the issues encountered during construction.
Introduction: MEA was asked to provide laboratory testing of pavement materials for the client.
Description: MEA laboratory staff performed Atterberg Limits, Grain Size Analysis, and Modified and Standard Proctor tests to determine the material’s properties.
Outcome: MEA’s laboratory prepared a report of the testing results of the testing for the client.
Introduction: MEA was asked to investigate the failure of a cofferdam.
Description: Investigation of the failure of a braced sheetpile wall failure ultimately due to underseepage. Performed a detailed design analysis of all geotechnical engineering aspects including subsurface investigation and laboratory testing, sheetpile earth and seepage pressure conditions, battered pile performance, coupled 2D and 3D seepage analyses, sheetpile uplift potential, event analysis and piping potential.
Outcome: Investigation of the failure of a braced sheetpile wall failure which was ultimately due to underseepage.
Introduction: A structure was damaged due to ground movement and MEA was brought in to help with stabilization.
Description: The work included examination of ground improvement treatment and measured ground movements from quick clays, settlement calculations, numerical analyses of ground movement and design/costs for different stabilization alternatives. Investigation basically determined that pre-construction treatment of deep-seated quick clays with wick drains and surcharging was insufficient resulting excessive post-construction movement and building damage.
Outcome: The investigation essentially determined that pre-construction treatment of deep-seated quick clays with wick drains and surcharging was insufficient, resulting in excessive post-construction movement and building damage.
Introduction: Forensic analyses of pumping an abandoned coal mine in Kentucky.
Description: This project consisted of assessing the hydrological impacts of the massive dewatering of a flooded old abandoned mine complex which is 150-200 ft deep. The pumping of this flooded mine complex extended for miles. To assess this impact, numerical analyses were conducted using MODFLOW program. To assess the hydrological effect from minewater pumping, the modeling had to not only include the multiple pump conditions but flow conditions through the entire mine complex and the recharge of the mine through backfilled mine openings exposed to surface flooding.
Outcome: MEA prepared an expert engineering report which include the hydraulic effect dewatering an abandoned coal mine in the neighboring mine complexes.
Introduction: Impact and mitigation analyses of the effect of mine subsidence on two pipelines.
Description: MEA was engaged by a major gas pipeline transmission company to evaluate the response of two 10in high pressure lines to mine subsidence movements from subjacent longwalling, and design hazard protocols and mitigation measures where needed. This first required statistical analyses of empirical data to determine the potentially adverse ground movements the pipeline will be subjected to. From FEM modeling of the predicted subsidence movements, the behavior of these pipelines was predicted. Mitigation measures were then successfully designed and installed where needed again with the use of FEM analysis. A telemetric monitoring system was also designed and installed to assess the real time imposed stresses and deformations from the mine subsidence movements.
Outcome: Successfully determined critical deformation conditions induced by longwall mine subsidence and recommended mitigation measures which has kept the transmission lines safe.