Hazard Reduction in Deep Excavations Execution

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.

Prefailure Deformation of Nailed Deep Excavations under Surcharge by Centrifuge Model Test

To study prefailure deformations in nailed deep vertical excavations under various surcharges, four centrifuge tests were used to explain the lateral deformation of facing, the fracture mechanism of cement facing, and the settlement profile of the ground surface. The soil used in this research was Firoozkooh sand No. 161. Both surcharge applying and excavation were performed at 40 g acceleration. The depth of the excavation was 30 cm, the length of the nail varied from H/3 to 2H/3 (H: excavation depth), and the nails were installed horizontally. The nails were made of brass pipes and then sand coated. The results showed that the effect of surcharge on the lateral deformation of the facing as well as the fracture mechanism of facing is obvious. Also, it was seen that the ground settlement profile is two-line or three-line at the moment of facing fracture and is affected by surcharge.

Risk Assessment in Deep Excavations and their Effect on Surrounding Structures : A review

—Construction is crucial to a country's overall economic growth, particularly in developing countries, in the current era of globalization. If construction operations are not carried out strictly according to a local or national building code, they might result in large-scale failures endangering human lives, personnel property, and the economic balance. It is vital to handle the construction process's risk elements. The self weight of soil behind the retaining line is the driving force and shear strength of soil is the resisting force as a result, deep excavations invariably cause lateral and vertical ground deformations. As a result of the produced ground deformations, nearby buildings and utilities become kinetically loaded. Risks associated with ground movement cannot be calculated solely using mathematical predicting models and engineering simulations as it needs to address the uncertainty of soil properties, Geo-materials, ground constitutive nature, building stage modelling, three-dimensional impacts of deep excavations, time-dependent natures of ground deformations, and the critical necessity to include human variables such as craftsmanship into prediction models are all important considerations.This article provides an overview of risk assessment and management technologies and approaches that have been adapted for use in deep excavations. This article presents a review of the most effective methods for evaluating hazards related with deep excavation and current mitigating techniques. Theoretical approaches to enhancing the safety of deep foundation excavation are examined in the context of a hospital building in Khartoum state and a residential district project in southern Jianxi province.