Geologiczno-inżynierska ocena wybranych gruntów jako podłoża autostrady A2wrejonie Grodziska Mazowieckiego i wyniki badań nad polepszeniem ich właściwości

The soils along a proposed new route of Highway A2 north of Grodzisk Mazowiecki between Tłuste and Żuków consists of three different classes of geological-engineering conditions: good, average and bad. Most of the area is characterized by unfavorable conditions because of high groundwater level. The study area is mainly covered by clays which are prone to emerge a frost heave. The analysis of the mechanical and physical characteristics of the soils showed that one of the soils did not meet the standard set for highways. Therefore the optimum soil composite and cementation methods have been employed. The suitability of the method of improving soils has been varified by means of such parameters as, compression strength samples containing from 4–10% of cement and the frost resistance index. The research revealed that samples containing from 4-8%of cement do not comply with the norms for highways. Despite the correct compression strength criterion for mixtures that contain 10% of cement, low value of frost resistance index limits the possibilities of using this cement-soil mixture in the upper layers of the ground. Based on the unfavorable geological-engineering conditions and results of cementation in the soils it turned out that they are still not useful for the proposed highway project.