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Abstract Rockfall and landslide prevention and stabilisation as well as risk assessment are essential for the design, construction and maintenance of structures in unstable slopes. Roads, highways and railways are frequently running in landslide-prone areas which often are seismic zones as well. The paper underlines the influence of water and shear parameters on slope stability, and the importance of determining the residual shear strength. Creeping causes excessive lateral pressures on structures; details for calculation are presented in this paper. Building in unstable slopes requires engineering flexibility and structures which can be strengthened step by step if necessary. This involves semi-empirical design (“active design”) based on calculated risk and the observational method including contingency plans and long-term monitoring. Several case histories demonstrate this engineering philosophy which has proved suitable for nearly 50 years.
ABSTRACT: Ground support comprises a wide field of geotechnical engineering. Therefore some special topics are selected: Reinforcement and dowelling of soil and rock by nails, anchors, piles and jet-grouting. Thus, the ground becomes more or less a compound body which locally can be considered a quasi-monolith. In the case of retaining structures or underground excavations, prestressed anchors are used in addition to conventional reinforcement. The paper focuses on retaining structures, underpinning of buildings, and tunnelling. Residual shear strength of the ground is considered an essential value for parametric design analyses and risk assessment, and the observational method is favoured over the fully-engineered design. INTRODUCTION Building in unstable, heterogeneous, or soft ground includes a significantly higher calculated risk than is experienced by the other branches of civil engineering. In most cases, sophisticated theoretical models and calculations simply feign an accuracy which in practice does not exist. Statistical investigations do not really solve the problem either. This refers to the ground parameters as well as to the climatic data. But, parametric studies are essential for a reliable risk assessment and to follow the concept of most probable and most unfavourable conditions. This involves designs which can be improved in steps during construction or even in the long-term according to the observational method. Unstable terrain requires a "semi-empirical" design method based on comprehensive monitoring - and pre-planned safety measures which allow for future strengthening if the results of long-term measurements require such. The observational method has also proved suitable for deep excavations in urban areas and for tunnelling. Reinforcing or dowelling of soil or rock is a very appropriate method to achieve such goals, because this technique is adaptable to practically all local conditions with regard to morphology, spacing, forces etc.
- Energy > Oil & Gas > Upstream (1.00)
- Construction & Engineering (1.00)
- Materials (0.83)
ABSTRACT: The paper presents a critical review of the state of the art of geotechnical engineering of natural slopes, cuts and fills in soil. Topics which are covered include the pre and post failure mechanics at the micro and macro scale, including discussion of contractant and other strain weakening soils, creep, progressive and retrogressive failure and fissured clays. Geotechnical investigation requirements and methods for analysis of stability and deformations, and for analysis of post failure velocity and travel distance are reviewed. It is concluded that many slope instability hazards may be managed by traditional factor of safety methods, but that it is important that the post failure behaviour be considered. Observational, and risk assessment methods may be more appropriate than the traditional methods in many cases. 1. INTRODUCTION 1.1 General Objectives of the Paper This paper sets out to present a critical review of the state of the art of geotechnical engineering of natural slopes, cuts and fills in soil. This includes site characterization, including the geology and hydrogeology, the establishment of the material properties and pore pressures, the mechanics of sliding at the micro and macro scale, analysis of stability, deformations pre and post failure, and management of the slope hazard. The emphasis is on practical issues, and the integration of engineering geology, hydrogeology, rock and soil mechanics. We will be seeking to demonstrate that it is now practical to quantify the potential post failure deformations sufficiently well that their assessment should be part of any geotechnical assessment of a slope. In this way, the engineering of a slope can be linked to the consequences of failure, allowing better management of the risks. We have also emphasized those situations which are not well modelled by conventional effective stress analyses.
- Asia > Japan (1.00)
- North America > United States > California (0.92)
- Oceania > Australia (0.67)
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- Overview (0.67)
- Research Report > New Finding (0.67)
- Geology > Structural Geology > Tectonics (1.00)
- Geology > Geological Subdiscipline > Geomechanics (1.00)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock (0.92)
- (3 more...)
- Geophysics > Seismic Surveying (1.00)
- Geophysics > Borehole Geophysics (1.00)
- Materials > Metals & Mining (1.00)
- Government > Regional Government > North America Government > United States Government (1.00)
- Government > Military > Army (1.00)
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- Asia > Middle East > Iraq > Kirkuk Governorate > Zagros Basin > Khabbaz Field > Shuaiba Formation (0.93)
- Asia > Middle East > Iraq > Kirkuk Governorate > Zagros Basin > Khabbaz Field > Nahr Umr Formation (0.93)
- Well Drilling > Drilling Operations (1.00)
- Well Drilling > Drilling Fluids and Materials (1.00)
- Well Completion (1.00)
- (10 more...)
A10 Motorway – Refurbishment Reitdamm: Stabilization of a Longtime Creeping Landslide of a Hillside Embankment
Bach, Dietmar (IGT Geotechnik und Tunnelbau Consulting Engineers) | Sönser, Sabrina (IGT Geotechnik und Tunnelbau Consulting Engineers) | Breymann, Helfried (Consulting Engineer) | Treichl, Hanspeter (ASFINAG BMG)
Abstract At the end of the 1970's the A10 motorway was constructed. One lot of this large infrastructure project was a 450 m long and 40 m high embankment dam situated on an inclined ground surface. Shortly after the beginning of construction of the engineered fill, geotechnical measurements showed movement of the embankment toe. The movement could not be stopped by reducing the rate of filling or periodically suspending the works. The increase of excess pore water pressure in a layer of saturated glacial lake clay, which was known to exist beneath the original ground surface, worsened the situation. Due to the required opening date of the highway the consolidation of the clay could not be undertaken. Therefore, extensive stabilization and dewatering works had to be installed during the construction period and in later years up to the present day. 1 History 1.1 Situation Brandecker (1976) investigated the geologic and geotechnical ground conditions. He emphasized in his report that the following stabilization measures should be carried out in order to guarantee a successful construction of the dam:Stone wedge used as a supporting foot for the dam Partial excavation of settlement sensitive soil layers Systematic dewatering of the whole dam basement Monitoring of the displacements during the building process The dam (500,000 m) was filled with excavation material from the Reit tunnel, which is situated at the east end of the embankment. It is based on an inclined surface consisting of silty sand and gravel layers with layers of glacial lake clay beneath. The crystalline basement existing below is composed of phyllite and sedimentary moraine material (Figure 1).
ABSTRACT: It goes without saying that every building activity leaves its mark on the existing natural conditions, often with surprising consequences. One of the few "safety" aspects generally taken for granted during the building of a structure is stability in space and time. In some cases, however, even this is not achieved. This is the case for construction in the landslide area located in St. Moritz in the Swiss Alps. SITUATION AND GEOLOGY The Brattas-Fullun landslide is located on the northern slope above the village of St. Moritz. The landslide is composed of a 600 m wide clastic flow and is bounded on both sides by parallel shear surfaces. The detachment zone is located on the southern edge of the terraced surfaces of the Val Saluver at an altitude of 2400 m a.s.l., and the area stretches over a horizontal distance of 1.5 km to a lower altitude of 600 m. The clastic flow may be divided into two zones (Figs. 1 and 2). The upper zone, which extends from the detachment zone between Sass Runz.l and Sass da Muottas to the crest at an altitude of approximately 2100 m, is composed of a rockfall. The lower zone, which is the actual Brattas-Fullun landslide, is composed of a thick soil mass which is moving downhill but is blocked at its foot by the Hotel Kulms rock ridge, after which the movement stops. The amount of material in motion is enormous and has been estimated to be about 10 million cubic metres. A drill hole was carried out at one location in the upper zone of the slope which revealed the main sliding surface to be at a depth of 60 m and the thickness of the entire sliding mass to be 87 m.
- Geology > Structural Geology > Tectonics (0.48)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock (0.45)
- Construction & Engineering (0.70)
- Materials (0.49)