In this article, the authors consider a completely new approach in design, which is related to the use of previously un-adapted technologies known to bridge engineering in geotechnical issues for prestressing of diaphragm wall during deep excavations execution. The bridge technology described here is the prestressing of concrete structures. Hazards related to deep excavations and methods of digging them, such as the ceiling method and top&down method, are presented. Current problems in supporting deep excavation slopes are related to the use of extensive quantities of materials (such as steel struts, ground anchors, or concrete and reinforcement steel). The authors’ method helps to achieve a higher level of sustainability, which is important in a modern approach to geotechnical engineering. The non-linear arrangements of the cables according to the occurrence of the prestressing moments for a given phase are presented. Results related to numerical analysis—showing the correctness of the method and cost optimization results, showing possible savings are presented. The article is a part of the set. In the second (already published) article titled “Modern Methods of Diaphragm Walls Design”, the authors present the concept of the calculation methodology for diaphragm wall design.

One of the most important subjects of geomechanics research is finding mathematical relationships which could correctly describe behavior of the soil under loading. Safety of every engineering structure depends strongly on accuracy and correctness of this description. As laboratory tests show, macroscopic properties of soil are complicated. Therefore, working out appropriate load-settlement relationships is considered to be a very difficult geomechanics tasks to solve. A majority of constitutive models proposed to date concern mineral soils and there is very little research related to modelling organic soil behavior under loading. In case of organic soils, due to their very complicated and composite structure, constitutive models are often formulated empirically based on laboratory tests of particular soils. The authors of this paper propose a 1-D rheological structure which accounts for complex behavior of soil related to the settlement process. The model simulates immediate reversible elastic settlement and plastic soil deformation as well as primary and secondary (creep effect) consolidation. Material parameters of the model were determined by a curve fitting procedure applied for a natural scale settlement test of plate foundation. The test was carried out in soil conditions connected with Eemian geological structure of Warsaw, i.e., Eemian glacial tunnel valley in Warsaw called Żoliborz Glacial Tunnel Valley filled with organic soils being up to 20 metres thick. This area has lately become an object of interest of investors as a site for building construction.

This article addresses hazard reduction in deep excavations. The authors present a possible combination of prestressing of concrete structures (from bridge engineering) and prestressed structures of diaphragm walls from geotechnical engineering science. This innovative concept has not yet been shown in scientific articles. The “Sofistik” software (with TENDON module–SYSP/AXES/TOPP/TGEO) and its use is shown, with graphical presentations of the suggested solution. The authors compare the provided solution through usage of Sofistik and Plaxis software. The results show possible strengthening of sustainable construction by limitation of hazards and decreasing costs (via limitation of use of expensive steel reinforcement).

Slab and pile foundations are one of the most popular solutions for transferring building loads to the ground. This is due to the combination of the advantages of direct and indirect foundations. Unfortunately, the lack of studies on this type of foundation that present the theoretical and practical dimensions of this approach is apparent. This article presents the theoretical background of this issue, capturing the advantages and disadvantages of this solution. The authors lean into the theoretical derivation by demonstrating various computational approaches. Thanks to the theoretical derivation and the citation of various computational approaches, it is possible to correctly determine the bearing capacity of the slab itself or the piles themselves in a slab–pile foundation. In addition, the authors have prepared numerical calculations based on theoretical considerations. The numerical analysis method shows the convergence of the selected theoretical method, which confirms the uniqueness of this computational approach through back analysis and validation of numerical models with Robot Structural Analysis software. The numerical consideration confirms the correct distribution of pile- and slab-bearing capacities; thus, it is possible to design the slab–pile foundation economically. With this verification, the design method of this type of foundation can be correctly determined.