Prove penetrometriche DP correlazioni punta aperta Le prove SPT in foro generalmente in letteratura considerano le correlazioni per la punta aperta (campionatore Raymond), le norme AGI 1977 ed anche le norme ASTM prevedono però che il campionatore può essere sostituito da una punta chiusa in caso di terreni granulari grossolani ove gli elementi hanno diametro…Details
More info on dedicated software for the checks of earth small dams The verification criterion of artificial dams works described bellow is valid for works with an embankment height smaller than 15 meters. From a static point of view, a global judgment on the stability of the work can be inferred from an approximated procedure…Details
Topographic profiles and elevation plans online With Geostru MAPS you can create digital terrain models, elevation profiles and contour plans, directly from online maps with just a couple of clicks. After assigning points through Point command, in Calculation menu you can find point’s elevation, trace the topographic section (altimetry profile), numerically edit latitude and longitude…Details
The limit state for liquefaction triggering is obtained using a neural network-based searching technique developed by Juang et al. 2000b. The technique involves the training of supervised feed-forward neural networks with the “full” database of case histories and its subsets or samples. The successfully trained neural network that generates the most accurate input–output relationship is adopted in the subsequent step for searching…Details
1. Charge limite d’un élément de fondation Qu Qu = Qpu + Qsu 1.1 Effort mobilisable sous la pointe Qpu Qpu= A·qu ou Qpu=ρp ·A·qu – A : section de la pointe – ρp : coefficient réducteur (cas de pieux ouverts, H, palplanches) – qu : contrainte de rupture : qu=kp· Ple* Fig 2. Schéma…Details
Screw-Piles Helical Anchors Soils This Guide should be used for preliminary calculations only and applies only to the deep installation of Screw-Piles and Helical Anchors in uniform soils. It is only applicable for design when the depth (D) to the top helical plate is greater than 10 times the diameter (B) of the helical plate…Details
Retaining walls are structures, which are used to retain the earth, to prevent from the sliding away. These structures are used for slope’s stability. Types of Retaining Walls are: Gravity Walls Reinforced Gravity Walls Brick Brick Masonry retaining walls Stone Reinforced Soil Walls Hybrid System Anchored Earth Tailed Gabion Tailed Concret Block Miscellaneous SLOPE by…Details
SPT conversion to N60 and N1,60 The most recent empirical correlations of NSPT, relative density and angle of shearing resistance of granular soils are calculated using the penetration resistance in terms of N60 (NSPT=N60 according to Cestari, 1996) or of N1,60, normalized value at a geostatic vertical pressure of 1 bar by applying the coefficient…Details
Ground Investigation Testing: Design investigations The depth of investigation shall be extended to all strata that will affect the project or are affected by the construction. • For dams, weirs and excavations below groundwater level, and where dewatering work is involved, the depth of investigation shall also be selected as a function of the hydro-geological…Details
The fundamental frequency of a site with the Nakamura’s method: The areas with a homogenous seismic behavior are identified with the methods of seismic micro-zoning which record, analyze and interpret the environmental seismic noise. The HVSR (Horizontal to Vertical Spectral Ratio) method, named also Nakamura’s method, is one of the most used to determine the…Details
Geofluid 2016: International Exhibition & Conference on Technology and Equipment for Prospecting, Extracting and Conveying Underground Fluids Geostru will be present, as in other years, at Stand N° 2 – PAD 2 – Aisle L. Geofluid2016_layout_Geostru Thanks to the full support of the market leader companies and the high professional profile of its visitors, Geofluid confirmed its consolidated leadership…Details
The bearing capacity of a shallow foundation can be defined as the maximum value of the load applied, for which no point of the subsoil reaches failure point (Frolich method) or else for which failure extends to a considerable volume of soil (Prandtl method and successive). Prandtl, has studied the problem of failure of an…Details
Slope stability analysis: The term slope means a portion of the natural slope whose original profile has been modified by artificial interventions relevant with respect to stability. The term landslide refers to a situation of instability affecting natural slopes and involving large volumes of soil. Introduction to stability analysis The resolution of a stability problem requires…Details
Shear check for retaining walls The check sections of the stem and footing of retaining walls are verified to shear without transverse reinforcements to shear (brackets, pins, bent bars) in general for massive structures but also for the purpose to simplify the execution on site. The computation of the shear check is based on the following:…Details
Computation of settlements induced by the seismic action The computation of settlements induced by the seismic action is affected by significant uncertainties. The values that are obtained applying the procedures described below must be intended only as guidelines. The settlement is considered to be the lowering of the surface level, or, the integral of the…Details
The article “Determination of geotechnical characteristic parameters” follows the base principles of the Eurocode.
“The characteristic value of a geotechnical parameter shall be selected as a cautious estimate of the value affecting the occurrence of the limit state.”
[EC7- 18.104.22.168 2(P)]
Defining the geotechnical characteristic value means therefore to choose the geotechnical parameter that influences the behavior of the soil in that particular limit state and adopt a value, or an estimate, in favour of safety.
If statistical methods are used, the characteristic value should be derived such that the calculated probability of a worse value governing the occurrence of the limit state under consideration is not greater than 5%.
Assuming, for exmple, a characteristic value of 26° for the soil friction angle with a 5% fractile, means to hypothesize that there is a probability of five percent that the real value of the friction angle is less that 26°.
A cautios estimate of the geotechnical parameters is obtained through the following formula:
where, for a normal distribuiton, for compensation of resistances (slope stability analysis, bearing capacity of shallow foundations)
in absence of resistance compensation (plinths, bearing capacity of deep foundations)
In the case of resistances compensation the characteristic value of the geotechnical parameter is close to the mean value.
In absence of resistances compensation the characteristic value is close to the minimum value.
It was performed a continous mechanic penetration test to a depth of 6.8 meters from ground level. The test was processed with the software Dynamic Probing, obtaining the values for the angle of shearing resistance shown in the table below:
According to the indications reported in the literature, the angle of shearing resistance does not follow the normal statistical distribution, but its tangent xi=tan(fi), so we transform the angles in tangent:
Mean value m(xi)= 0,547799;
Standard deviation s(xi)=0,009417
For compensated resistances
The value of the distributed parameter is calculated as:
xi=0,547799-1.645*0,009417/root(34)=0.54518, with the transformation in angle, arctg(0,54518) we obtain 28.6°
For not compensated resistances
The characteristic value of the distributed parameter can be calculated as:
xi=0,547799-1.645*0,009417=0,532307, trasformed in angle arctg(0,532307)=28.0°
In this case (large sample) the difference between the obtained values is minimal, but the difference may become substantial for small samples (n<30) as in the majority of cases and for some geotechnical parameters, such as cohesion, which distributes its statistical value according to a logarithmic law.
The software CVSOIL offers the possibility to analyze: numerous samples, dispersed samples, highly dispersed saples, linear distribution, tangent, logarithmic etc.
CVSOIL simplifies the user’s work allowing to automatically acquire the data to estimate from Excel, memory or directly from the software Static Probing and Dynamic Probing.
In this short video you can see how data is beeing processed in CVSOIL
Crack, Serial and Keygen: here’s what to do Are you looking for a cracked version of GeoStru software? Would you like to download a serial or a keygen (key generator) to use GeoStru software for free? Perhaps you are not aware that using cracks, keygens and serials is not only illegal: it also exposes your…Details
Sheet Pile Walls – Overview In order to have a more efficient usage of construction areas in congested urban areas a vertical development of buildings becomes necessary. Currently we more often face situations where urban buildings need as many parking spaces, so, due to lack of space, that requires the development of several underground floors.…Details
Limit equilibrium methods for slope stability analysis do not, in general, satisfy the overall equilibrium conditions; they must make assumptions regarding the inclination and location of the interslice forces. An alternative slope analysis based on the discrete element method is presented to avoid these drawbacks. A slope in the present model is treated as comprised…Details