JASA Engineering Inc. specializes in Geotechnical Engineering. Through site specific soil and groundwater assessments and a comprehensive understanding of soils, we provide solutions and sound recommendations for a variety of geotechnical subjects including:
JASA conducts a variety of Geotechnical Investigations, each of which is catered specifically to the site in question and its proposed development or requirements. Through investigation of subsurface conditions and materials, we can determine the relevant physical, mechanical, and chemical properties of the materials, evaluate the soil and subsurface conditions, and provide design recommendations for foundations and general site construction.
Our field work typically includes:
Our geotechnical reports typically include:
A slope stability analysis is performed to assess the safety, stability and/or reliability of natural or man-made slopes. Construction at or near the top, toe or midway point of a slope can attribute to failures within the sub-soil strata. During a slope stability assessment, determination of potential failures is investigated through a variety of methods including intrusive subsoil investigations and complex software analysis. A construction plan incorporating a slope assessment provides safety, reliability and sound economics to your overall design. Should a slope be determined unsafe, re-design of the slope or design of remedial measures such as stabilization or barriers can be implemented.
Monitoring of the slope can also be conducted. Periodic inspections through installed monitoring equipment and/or surveying methods can provide valuable information regarding the stability or movement of the slope in question.
An accurate pavement design is critical in providing a long life to your asphalt surfaces. Whether it is for major roadways designed for heavy duty commercial trucking or parking lots with light duty traffic, the proper design can mean the difference between effective construction and constant pavement failures and repairs.
Pavement types, base layer thicknesses, and materials utilized all have a bearing on the effectiveness of the pavement structure. Subgrade soils and base courses help bear the load of the traffic. Assessment of the subgrade soils and base courses assist in providing the information needed to design the pavement. Utilizing this information, along with AASHTO methodology, a sound pavement design can be provided.
Piles are designed to support a variety of structures. Dependent upon the type of structure being erected and the subsoil conditions encountered, different pile types will be recommended. Piles transfer the load of the structure into the underlying soil or rock layers either by skin friction and/or end bearing.
End bearing piles are used for the direct support of vertical loads and transfer the load through soft soils that are not capable of supporting loads to an underlying hard layer. Friction piles are used in soils of a fairly uniform consistency to laterally transfer the load to the surrounding soil by means of friction. Many piles carry loads by a combination of friction and end bearing.
During a geotechnical investigation, skin friction and end bearing values are determined based upon soil conditions encountered and assist in providing suitable foundation recommendations.
Soil bearing capacity measures the capacity of the soil to support the applied loads without failure or excessive settlement. Design recommendations based upon anticipated soil types, as well as field confirmation during construction can be provided.
Through a variety of testing methods, the design ultimate and allowable bearing capacities are calculated and field confirmations are provided. An ultimate bearing capacity is the maximum pressure the soil can withstand without undergoing shear failure; an allowable bearing capacity is the maximum pressure the soil can withstand considering shear failure and maximum allowable settlement, and utilizing a factor of safety.
Following earthwork guidelines ensures a solid foundation for your construction projects. Subgrade preparation, fill placement, proof-rolling operations, trench backfill control, and compaction control are some of the guidelines employed. Utilizing the correct types and lift thicknesses of fill soils are crucial to correct placement and required compaction of subgrade soils.
During a geotechnical investigation, bedrock coring can be conducted to assist in determining foundation design. Bedrock cores are cylindrical samples retrieved during drilling that show the composition of the underlying rock and provides the subsurface conditions at specific borehole locations. Rock quality designation (RQD), compressive strength and mineral composition can all be determined through bedrock coring.
RQD values are used as a basis for making preliminary design decisions involving estimation of required depths of excavation for foundations of structures. The RQD values also can serve to identify potential problems related to bearing capacity, settlement, erosion, or sliding in rock foundations.
Accurate assessment of the in situ subgrade soils is an essential part of the planning and development process. Subgrade issues can cause extensive delays or costly repairs. Soil stabilization (including geotextile placement or soil cementing), soil permeability, frost assessments, undercutting/reworking requirements, and granular types and placement are typical questions faced by many construction projects. Through visual assessments and witnessing of proof-rolls, as well as laboratory testing, recommendations can be made in regard to corrective actions in order to meet the design requirements.
Clay soils, in particular, are susceptible to consolidation under load and can cause settlement of the foundation. At the opposite end of the spectrum, these same soils are susceptible to swelling causing an upheaval beneath the foundation structure. Laboratory testing of the soils for permeability/hydraulic conductivity, liquid/plastic limits, consolidation, and swell can provide information vital in accurate design of your foundation. This information is also required in determining soil suitability for use in stormwater retention ponds and other construction designs.
The hydrocarbon compound methane, CH4, is an odourless, colourless, tasteless, non-poisonous gas that is combustible when the concentration is between the lower explosive limit (LEL) of 5 percent methane in a mixture of oxygen, and the upper explosive limit (UEL) of 15 percent methane in a mixture of oxygen.
Methane generation is a naturally occurring process involving the anaerobic biodegradation of organic matter. Low concentrations of methane are present in nature and in the atmosphere naturally. Methane is lighter than air and under constant atmospheric conditions it will have a tendency to rise through the air.
Methane does not move through water; and water acts as a barrier to methane migration. Migration through unsaturated soils is influenced by changes in barometric pressure, air void space between soil particles, and soil temperature.
The identified hazards associated with methane are in its susceptibility to ignite when mixed with oxygen in portions between the LEL and UEL; and in its lowering of the available oxygen content in air.
A methane investigation can be carried out as a standalone assessment or during the conducting of geotechnical drilling. Wells are developed for monitoring of the well headspace hydrocarbon vapour concentrations, and soil and water samples are obtained for select chemical evaluation.
Should elevated methane levels be detected, a methane management plan can be developed and implemented. Typical management plans include venting system designs and specifications, construction and installation reviews, monitoring programs, and operating and maintenance manuals. With proper planning and management, elevated methane levels within the subsoil layers should neither restrict nor hamper commercial development or use of a project site.
During earthwork operations, the impact of certain construction activities to surrounding sites can be detrimental. Vibratory compaction techniques, pile driving, and rock excavation in close proximity to inhabited buildings can cause noise issues due to the continuous and repetitive nature of the work, as well as having a potential for causing structural damage. At close proximity sites, monitoring of vibration and/or noise is critical for staying within allowable thresholds and maintaining a positive relationship with neighbors through factual communication.
Groundwater levels can have a dramatic impact on your existing foundation and/or construction design. Periodic or seasonal groundwater level monitoring can be beneficial in determining a design suitable for the site specific requirements or for remediation of groundwater issues. Through the installation of piezometers (typically 1” to 2” slotted PVC standpipe), groundwater measurements can be taken at specific locations throughout the development site. This information can be utilized to determine groundwater levels, degree of seasonal water level fluctuation, and any remedial or design requirements based on the information acquired. A pump test can also be conducted to assess the volume of water and pumping rates needed for dewatering of deep excavations such as multi-level underground parkade.