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On geotechnical design according to residual shear strength
Koudelka, Petr
The paper consider on possibility and effectivity of a new concept of ULS design on residual shear strength based. Values of residual shear strength are the most reliable and in opposite, applied peak values of shear strength are the most favorable and applicable for states of small deformations only. The paper presents results of a prior analysis of slope stability and compares designs applying values of residual shear strength and peak shear strength. Some recommendations are included.
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Shear strength of sand under very low normal load
Hudek, J. ; Koudelka, Petr
Solutions of some extraordinary geotechnical problems need knowledge of shear strength in a scale of very low normal stress. An example is physical modelling of soil mass behaviour using medium or little samples. The paper deals with results of testing a very dry uniform quartz sand of medium size. Resulting values of effective shear strength for the normal stress scale till of 25 kPa are compared with former testing of the same material in other scale of 63 – 163 kPa.
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Application of soil designes values according to ULSD of EC 7-1 in Czech conditions
Koudelka, Petr
Some contemporary European codes (e.g., EC 1, EC 7-1) and standards (e.g., ČSN 73 0031) have taken into account in their theoretical bases a special granular character of soils and rocks with a different extent. The EUROCODES, i.e. EUROCODE 1 (EN 1991-1) "Basis of design and actions on structures - Part 1: Basis of design" and EUROCODE 7-1 (EN 1997-1) "Geotechnical design - Part 1: General rules" consider underground environment/mass in the same way as the other structures (e.g. steel, concrete, masonry, timber) without any theoretical exception for analyses of three-phase granular material structures. Thus, using theory of the Ultimate Limit State Design (ULSD), a statistical definition of characteristic values and several partial factors have been considered along with material partial factors for material design values of the soil mass properties.
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Experiment E5/0,1 with lateral passive pressure during rotation about the toe - granular mass deformations
Koudelka, Petr ; Bryscejn, Jan
A basic physical experimental research of lateral passive pressure is in progress at the Institute. The research is composed of three doubles of the same experiments with three basic retaining wall movements: rotations about the toe and top and translative motion. The experiment E5/0,1 with passive pressure and pressure at rest during wall rotation about the toe was carried out in 1st half 2012 and it was the first of the same experiment double (the 2nd one was the experiment E6/0,1 finished in the early 2013. Both experiments together should prove a real behaviour of non-cohesive mass acting on moving wall. The behaviour appears distinct from a theory of EUROCODE 7-1 contemporaneously used. Each of experiments has brought a huge data quantity. The paper shows mass deformations and slip surfaces of the experimental sandy mass.
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Process of lateral passive pressure acting in a sandy mass
Koudelka, Petr
The paper presents the results of physical experiment both with the passive pressure and the pressure at rest of the ideally non-cohesive sand on a retaining wall rotated about the top. The results are analysed and compared according to relevant requirements and recommendations of the final draft of EC 7-1(2004) and ČSN 73 0037. A preparation state of a next repeated physical experiment with passive pressure and pressure at rest to prove the results is mentioned.
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Podobnost plošných základů podle ČSN 73 1001
Koudelka, Petr
Now, that the translation into Czech and the National Annex of EC7-1 (EUROCODE 7 - Geotechnical design, Part 1: General rules) are carried out it seems convenient to make a broad comparative analysis of the EC7-1 and ČSN 73 1001 design procedures. The calculating procedure according to ČSN 73 1001 requires 8 inputs, the similar procedure according to EC7-1 requires 10 inputs. These numbers of inputs yield a huge number of combinations for a comparative analysis. The paper deals with a similarity solution of bearing capacity of shallow foundations according to ČSN 73 1001. The solution should form the base of the comparative analysis base for simpler numerical analysing.
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