Papers by Keyword: SPT

Abstract: The maximum load carrying capacity of bored piles is a complex problem because it is a function of a number of factors, these factors include methods of soil exploration, ground water condition, types of grading of concrete, quantity and quality of concrete. The knowledge of Geotechnical test is important for the most economical design of the piles. This paper describes some important aspects of field investigation, design and construction of in-situ bored pile foundation, field pile load test of experience gained from the construction of the pile at a site in Aathoor in Tamil Nadu, India. The site was fully sandy soil from existing ground level. The design of bored pile under axial compression was done using Empirical formula, pile load test and by using PLAXIS 2D software. Results were compared with vertical load and settlement in this site.

Abstract: The density of the sand is important factor for its engineering properties, There are many methods to evaluate the sand density, just the results may be differences, usually means, this is the test error of the different test methods. In fact, the reasons of the sand formation and buried conditions, sand particle shape and size, sand gradation, groundwater etc. are also the important factors for its engineering properties, but these factors are often ignored. Bearing pressure of confined water will change the distribution of the effective weight stress in soil and the abnormal phenomenon of sand density will appear. In the project, the cause analysis of sand density require attention. According to theoretical knowledge, to identify applicable conditions of the various evaluation methods and their advantages and shortcomings.

Abstract: Basing on diffusion radius formula of pressure grouting which was deduced by the Darcy's law in groundwater dynamics and connecting with engineering example, this article introduces the construction parameters and analyzes results of pressure grouting. Several methods including Re-grouting, coring method and SPT were used in the effect detection, it turns out that the slurry owns a consolidation and filling effect around the grouting holes when it is injected into soil. This effect can reduce the porosity and moisture content of soil, then the foundation bearing capacity is improved and the settlement can be reduced. Practice has proved the feasibility of pressure grouting in repairing soft foundation of important buildings, so it is a valuable reference to foundation reinforcement under similar conditions.

Abstract: Based on survey of the Bachu-Jiashi earthquake liquefaction sites, much new basic liquefaction information were obtained and China’s liquefaction database was enriched. A detailed investigation of the Bachu earthquake liquefaction site was conducted, in which three kinds of in situ test measures were used to obtain the site information, and given China mainland SPT data of liquefaction site increase by 40%. By site investigation, international standard liquefaction site CPT data were obtained, and also, the first measurement of liquefaction site data by SPT and CPT index was conducted. With the new data, the feasibility of liquefaction discrimination methods of China was inspected.

Abstract: Through the Bachu-Jiashi Ms6.8 earthquake liquefaction investigation and test, obtain the 47 the standard penetration test date, examine the existing standard applicability based on standard penetration test of soil liquefaction identification method, and put forward the new sandy soil liquefaction evaluation formula. Analysis shows that the current assessment formula base on SPT counts of soil liquefaction are not applicable to Xinjiang region, will give the risky results. In the new survey data of soil liquefaction evaluation model established of five parameters by the earthquake intensity, the measured SPT counts, datum SPT values, groundwater level, and sand buried depth. The datum SPT values, the influencing coefficients of water and sand depths are gain by a normalized method and by an optimizing method. Establish new formula of soil liquefaction evaluation to the success judging rate is higher, the model shows that constructing reasonable and calculation formula is reliable, can be employed for regional code formulation in Xinjiang area.

Abstract: The serious soil liquefaction phenomenon in Bachu-Jiashi earthquake on 24th February, 2003, which is the most prominent phenomena of sand liquefaction since the Tangshan Great Earthquake in 1976. Based on the earthquake liquefied investigation, inspect SPT and CPT applicability in situ tests. The results show that our country SPT specification and CPT specification of non-liquefied sites evaluation rate is higher than liquefied sites evaluation success rate, the liquefied sites evaluation rate are 88% and 88% respectively, but for liquefied sites evaluation rate are 38% and 55%. The result is tends to danger and the reason need further investigation, so establish a suitable liquefied prediction method should be to the future work in the local area.

Abstract: Take February 24, 2003 the Xinjiang Bachu-Jiashi area liquefication investigation as a foundation, using the SPT count as an indicator of liquefaction decision, liquefied decision methods of sites are considered at domestic and abroad, in which Chinese code liquefied prediction method and Seed-Idriss method are included. The result indicated that our country code and the Seed-Idriss method in liquefied the location prediction success ratios are only 43% and 48%, is in favor of the danger obviously. The reason possibly is the formation of SPT data mainly from the local area, but the Bachu-Jiashi area soil is quite different, therefore is worth the deep research.

Abstract: The simplified of fluctuating wind field and the basic theory of Spectral Proper Transformation（SPT）were expatiated. SPT was used to simulate the random wind field on long-span cable-stayed bridge, then the random wind field of the bridge was simulated by MATLAB program, an actual example was used to validate the validity and correctness of the MATLAB program. The results showed that SPT had the advantage of explicit physical meaning, high computational efficiency. It is an effective method to simulate the random wind field.

Abstract: In this paper, software Inet 3.0 is applied to generate topology, which randomly generates dynamic topology nodes. Based on dynamic shortest path algorithms put forward by P.Narvaez, Xiaobin et al, we analyzed the time efficiency of dynamic and static shortest path algorithms, the different time efficiency inner dynamic shortest path algorithms, and the relationship of time efficiency between topology and dynamic shortest path algorithms. The result shows that Xiaobin algorithm is statistically better than Narvaez algorithm about 20-30 percent. Dynamic algorithms are not always better than static algorithms considering the amount of changed topology. Dynamic and static algorithms are roughly same when the amount of changed topology holds 10 percent. Dynamic algorithms perform better when less than 10 percent, otherwise static algorithms will be better. The time efficiency of dynamic algorithms is related to special topology.

Abstract: A method for joining metals in the semisolid state is presented. A model alloy Sn-15%Pb was used to demonstrate the concept. By presented process, dendritic microstructure of the weld zone can be avoided. Moreover, near-weld zone of the cold worked substrates which is affected by heat would have a globular structure due to a thermomechanical treatment. The two substrates were heated up locally in the joint line to the semisolid temperature range. At this point a stirrer was introduced into the weld seam in order to mix the two sides into a single uniform joint. Localized mechanical properties of different zones were examined using Shear Punch Test (SPT), showing a good strength in the weld zone and thermomechanically affected zone.