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Deep vibro compaction (vibroflotation) is a soil improvement technique, which was patented by the company Keller in the 1930s and since then it has been continually developed and has been successfully used worldwide for deep compaction of granular soils. The methods for quality control of the compaction works are largely empirical in nature and therefore often unreliable. In a current research project, fundamental experimental investigations on real‐time quality control for the deep vibro compaction were executed. Large‐scale test measurements and numerical simulations were performed to investigate the three‐dimensional vibrator movement during the compaction process. Reliable measurements with measuring instruments on the vibrator tube during the compaction process have been conducted within the current large‐scale field tests. This paper presents the layout of the large‐scale in‐situ tests, moreover, selected test results are shown, and possible indicators of the changing soil conditions are discussed.

Geotechnical and environmental investigations for the planning of remediation measures are often reduced to the minimum required by national standards and authorities – or even less. This paper will highlight the positive effects of increased investigation efforts on reduction of total remediation costs at a specific site. The subsoil of this site is partially contaminated with perchloroethene. The site investigation included two campaigns of Membrane Interface Probing (MIP). The results of the MIP investigation were validated by taking depth‐oriented soil and groundwater samples. This high resolution of site characterization aimed to identify the contaminated hot spots as prerequisite for successful site remediation. A conceptual site model containing the spatial distribution of the contamination and the lithology was generated for the area of interest and was continuously updated during the investigation period. Based on this model, the architecture, volume and size of the contamination source zone that has to be treated was estimated with increasing stringency.

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Jet grouting is a technique to deliver oxidizing or reducing reagents directly into source zones in heavily contaminated industrial sites. The advantage is a forced mixing of contaminant and reagent, eliminating various risks posed by an inhomogeneous, layered subsoil. The feasibility of this approach was demonstrated at a former chemical laundry in Zwölfaxing, near Vienna, Austria. After two extensive investigations, two remediation campaigns were conducted with extensive monitoring and sampling in between to study the effects of locally set measures on the overall site. Samples taken from core drillings and liner samples as well as membrane interface probes (MIP) were examined and compared to data obtained from concentration measurements at observation wells. This contribution demonstrates the effectiveness of jet grouting and presents a novel approach using MIP sounding for assessing remediation success. This sounding technique enables investigating a zone of highly contaminated subsoil before and after the treatment, with measurements directly showing the dechlorination success.