Determination of swell index and swelling pressure from suction tests – a case study of Neogene clays from Warsaw (Poland)

Abstract

The pa per pres ents the re sults of swell in dex, swell ing pres sure and soil suc tion tests car ried out on Neo gene clays from War saw, de pend ing on the wa ter con tent, clay frac tion, liq uid limit, plas tic ity in dex, cat ion ex change ca pac ity, and con tent of clay min er als and beidellite. These clays are con sid ered ex pan sive soils in Po land, as they are vul ner a ble to wa ter con tent vari a tions in the ac tive zone, which re sult in their vol ume change and, in con se quence, cause dam age of foun da tions and other con struc tion el e ments. A num ber of phys i cal, chem i cal and min eral prop er ties were de ter mined for these clays. The swell ing tests were car ried out on sam ples precompacted in Proc tor ap pa ra tus, at var i ous ini tial val ues of wa ter con tent. The anal y ses have shown ex po nen tial re la tion of swell in dex, swell ing pres sure and suc tion ver sus wa ter con tent. In ad di tion, the in ves ti gated re la tion ship be tween the suc tion and swell char ac ter is tics of tested clays shows good cor re la tion as a power func tion be tween these pa ram e ters. In ad di tion, va lid ity of cor re la tions be tween fit ting pa ram e ters of ob tained re la tion ships and soil in dex prop er ties, such as clay frac tion, liq uid limit, plas tic ity in dex, cat ion ex change ca pac ity, and con tent of clay min er als and beidellite, have been dem on strated. The em pir i cal re la tions are char ac ter ized by high val ues of the cor re la tion co ef fi cient. A very high fit has also been found for a pro posed re la tion ship be tween the swell in dex and swell ing pres sure for tested clays.

Energy efficiency in the polish residential building stock: A literature review

“…The earliest energy efficiency regulations in modern Poland date were developed after World War II. Formal needs in the field of permissible heat losses, expressed by the heat transfer coefficient, have been formulated in Poland since 1957 [35]. As shown in Fig.…”

“…The revised requirements of 1974 [36] and 1982 [37] were updated under the influence of the oil crisis [38]. According to Wójcik (2018) and up to 1985, the calculated energy usage of typical Polish buildings was 240-380 kWh/m 2 [35]. In the years 1991-1992, it was required not to exceed 160-200 kWh/m 2 (depending on the purpose of the building) [39], 1993-1997 it was 120-160 kWh/m 2 since 1998 it should be no more than 90-120 kWh/m 2 [40].…”

“…In parallel to the evolution of building energy performance regulations, Poland enacted in 1998 a thermo-modernization law [35,49]. The Thermo-modernization Act of 1998 allows subsidizing the refurbishment of buildings from the state budget to reduce heat energy use [22].…”

“…The Polish government identified increased energy efficiency as one of its priorities in its long-term energy policy. Poland has had an old tradition of developing ambitious and consistent energy efficiency regulations for building since 1957 [35]. The Polish building regulations are adopting the EPBD requirements and getting closer to the EU 2030 and 2050 carbon targets.…”

Semi-Empirical Model for Predicting the Swelling Stress of Compacted, Unsaturated Expansive Soils

“…Therefore, soil suction is a significant parameter to be used for the prediction of swelling stress of heaving soils. Also, the investigation conducted by [26] on the swelling stress and swell index from the suction test on pre-compacted Neogene clays in Poland (Warsaw) shows an exponential correlation swelling stress and the suction. The suction increases when swelling stress increase.…”