In 2019, a geotechnical investigation and slope stability evaluation were conducted for an existing wind turbine site in the Long Point region of Southern Ontario, on the northern shoreline of Lake Erie. The investigation was followed by real-time geotechnical monitoring with an automated alarm system. The site features a 30-m high sandy bluff and evidence of past shoreline retrogression is apparent in satellite imagery and field observations. Geotechnical instrumentation was installed to provide on-going monitoring of the slope and to provide early warning for ground movements that could potentially affect the nearby wind turbine.

Two geotechnical borings were advanced between the crest of the bluff and the existing wind turbine, located about 60 m north of the crest at the time of the investigation. Sandy soils were encountered at surface to about 13 m depth, underlain by a siltier layer extending to borehole termination at 35 m depth. Thin (0.3 to 0.7 m), intermittent clay seams (CL) encountered within the silty layer indicate the presence of potentially weaker seams in the bluff. Groundwater was encountered at 17 m depth, about 6 m above lake level. A pair of nested vibrating wire piezometers was installed in one borehole using the fully-grouted method, and an in-place inclinometer string was installed in the other borehole.

The existing slope was modelled based on the observed site conditions and calibrated to reflect a pseudo-static state of stability at the bluff. Changes in groundwater and lake water levels, seepage at the bluff face, rainfall events and soil suction are all expected to influence the stability of the existing slope. Monitoring data obtained from the installed instrumentation combined with periodic field evaluations is anticipated to allow for further model refinement and possibly aid in the identification of precursory environmental factors leading to further erosion and instability.

In the current state of practice in Eastern Canada, the potential of ground motion amplification is typically assessed using the site amplification factors recommended by the National Building Code of 2015 (NBC 2015) or by performing equivalent linear ground response analysis, which considers an unrealistic assumption of constant dynamic properties. This paper compares site amplification factors from the National Building Code of Canada and computed using nonlinear and equivalent linear 1D ground response analysis. For a wide variety of soil sites in Quebec, dynamic simulations were conducted using the software DeepSoil to compute site specific soil amplification factors. The results suggest that the NBC 2015 may not be always conservative, and that the nonlinear analyses predict soil amplification factors often higher than the code. Notably, the disparity between the NBC 2015 predictions and those from the nonlinear analyses is greatest close to the site natural period or at periods slightly longer than the natural period, because of period lengthening effects due to strong nonlinearity of the soil behavior. At said periods, the amplification factors from nonlinear analyses present a sharp peak not included in the code.

Medium density polyethylene pipes (MDPE) are widely used for gas distribution systems in Canada and worldwide. These pipes are often exposed to relative ground movements resulting from landslides and earthquake. The effects of the relative ground movement on the pipes are influenced by the presence of lateral branches and the Tee-joint connecting the branch. Only a limited study is currently available in the literature on studying the behavior of branched pipe subjected to ground movements. This paper presents an experimental investigation of a branched MDPE pipe subjected to axial ground movement. A test with a 60.3 mm diameter gas distribution pipe is conducted using the laboratory facility at Memorial University of Newfoundland. Pipe wall strains and soil pressures around the pipe are measured to capture the mechanism of soil-pipe interaction. Test results reveal that the pullout force and pipe wall strains are significantly influenced by the Tee-joint. The elongation of the flexible MDPE pipe also contributes to the pipe deformations and wall strains.

There are many small earth dams perched high above the floor of the Okanagan Valley in British Columbia. Some of these dams pose a significant potential risk for destructive debris flow generation if they become breached. A relatively small outburst can trigger a much larger volume debris flow downstream of the dam. The failure of the Testalinden dam in the southern Okanagan region in June 2010 clearly demonstrated the destructive power of a debris flow triggered by the water released by a breach through a poorly maintained dam. Homes were destroyed and the property was damaged. This paper presents a methodology for preliminary assessment of potential debris flow initiation hazards caused by the breaching of small earth dams using digital elevation models, available maps, and limited monitoring records of dams. Further research can assist dam safety officers in better ranking the consequences of dam failure in sensitive environments. Empirical equations are used to predict the peak outflow if a breach occurs in a small earth dam. The creek gradient and the estimated height of water or outflow per unit width in the creek channel resulting from the outflow are used in debris flow initiation criteria to delineate possible locations along a creek where a debris flow may initiate. If debris flow initiation were possible, this would trigger the need for the more detailed assessment of dam failure consequences and will likely result in a higher dam failure consequence classification compared to consideration of flooding only.

Seismic response analyses at sites in eastern Canada is becoming more common than in the past with the typical approach being to use an equivalent linear site response model such as SHAKE. The authors conducted such site response analyses for several building and bridge projects in eastern Canada over the past years under a variety of design earthquake hazard levels, ground conditions and design objectives. The paper discusses the details of several case histories, the approaches used and observations on the outcomes achieved.

Of interest will be the observation that in these cases the seismic ground response is lower than would have been achieved using code-specified spectral values or cyclic-stress ratios obtained using simpler methods of analyses. The case histories also present an interesting array of input ground motion (both synthetic and recorded), methods of scaling (both linear and spectra) and design objectives (both liquefaction assessment and site-specific design spectra). Ground conditions vary from deep Champlain Sea clay to thick till, and intermediate ground conditions.

The results obtained represent valuable examples of the value of these types of analyses when properly done and would suggest that their more routine usage is warranted from a cost-benefit perspective. In some cases, the amplification of short period ground motions is much higher than expected for some earthquake records and ground conditions.

The Champlain River and its tributaries are located in the Champlain Sea formation and is the scene of a retrogressive clay slump and lateral spreading. In April 2017, a typical retrogressive clay landslide occurred in the territory Saint-Maurice, Municipality of Quebec. Aerial shots were undertaken a few days subsequently and have captured the scene of the landslide. Further data was collected with a LIDAR survey a few months after the slump. Finally, an extensive geotechnical borehole investigation was conducted in 2017 and 2018. Rapid data acquisition, a few days after the event was critical to this study. The aerial photography indicated that there were two levels of landslides associated with successive slide circles and the steps of theses levels disappeared the next year due to surface erosion. These levels allow us to validate our reverse landslide modelling.

Since the occurrence of the clay slump, it is possible that further slumps have occurred upstream and downstream and the risk of new landslides has increased. The conventional approach consisting of modelling several consecutive breaking circles using parameters from the reverse study may be hazardous because it is difficult to anticipate the quantity of levels that may occur according to the height of a bank.

LIDAR mapping technology allows us to observe landslides that have occurred in the past. With software like ETL (Extract, Transform, Load) and using an algorithm of LIDAR data classification we are able to eliminate ground vegetation and show the scars of older landslides. Our case study demonstrates that the longest historical slump spread observed on the bank of a tributary of the Champlain river is 57 m.