Subsurface lithology and seismic site classification of Lucknow urban center located in the central part of the Indo-Gangetic Basin (IGB) are presented based on detailed shallow subsurface investigations and borehole analysis. These are done by carrying out 47 seismic surface wave tests using multichannel analysis of surface waves (MASW) and 23 boreholes drilled up to 30 m with standard penetration test (SPT) N values. Subsurface lithology profiles drawn from the drilled boreholes show low- to medium-compressibility clay and silty to poorly graded sand available till depth of 30 m. In addition, deeper boreholes (depth >150 m) were collected from the Lucknow Jal Nigam (Water Corporation), Government of Uttar Pradesh to understand deeper subsoil stratification. Deeper boreholes in this paper refer to those with depth over 150 m. These reports show the presence of clay mix with sand and Kankar at some locations till a depth of 150 m, followed by layers of sand, clay, and Kankar up to 400 m. Based on the available details, shallow and deeper cross-sections through Lucknow are presented. Shear wave velocity (SWV) and N-SPT values were measured for the study area using MASW and SPT testing. Measured SWV and N-SPT values for the same locations were found to be comparable. These values were used to estimate 30 m average values of N-SPT (N
 30) and SWV (V
 s
 30
 ) for seismic site classification of the study area as per the National Earthquake Hazards Reduction Program (NEHRP) soil classification system. Based on the NEHRP classification, the entire study area is classified into site class C and D based on V
 s
 30
 and site class D and E based on N
 30. The issue of larger amplification during future seismic events is highlighted for a major part of the study area which comes under site class D and E. Also, the mismatch of site classes based on N
 30 and V
 s
 30
 raises the question of the suitability of the NEHRP classification system for the study region. Further, 17 sets of SPT and SWV data are used to develop a correlation between N-SPT and SWV. This represents a first attempt of seismic site classification and correlation between N-SPT and SWV in the Indo-Gangetic Basin.

Seismic Site Classification and Correlation between Standard Penetration Test N Value and Shear Wave Velocity for Lucknow City in Indo-Gangetic Basin

An investigation on the Su–NSPT correlation using GMDH type neural networks and genetic algorithms

Review of correlations between SPT N and shear modulus: A new correlation applicable to any region

Site effects primarily depend on the shear modulus of subsurface layers, and this is generally estimated from the measured shear wave velocity (Vs) and assumed density. Very rarely, densities are measured for amplification estimation because drilling and sampling processes are time consuming and expensive. In this study, an attempt has been made to derive the correlation between the density (dry and wet density) and V-s/SPT (standard penetration test) N values using measured data. A total of 354 measured Vs and density data sets and 364 SPT N value and density data sets from 23 boreholes have been used in the study. Separate relations have been developed for all soil types as well as fine-grained and coarse-grained soil types. The correlations developed for bulk density were compared with the available data and it was found that the proposed relation matched well with the existing data. A graphical comparison and validation based on the consistency ratio and cumulative frequency curves was performed and the newly developed relations were found to demonstrate good prediction performance. An attempt has also been made to propose a relation between the bulk density and shear wave velocity applicable for a wide range of soil and rock by considering data from this study as well as that of previous studies. These correlations will be useful for predicting the density (bulk and dry) of sites having measured the shear wave velocity and SPT N values.

http://iopscience.iop.org/article/10.1088/1742-2132/13/3/320/pdf

Correlation of densities with shear wave velocities and SPT N values

Compaction characteristics of soils being very important from field application point of view, any attempt to develop correlation equation to predict the same should be rational and universally applicable. It has been reported in the literature that the plastic limit of soils bear a good correlation with their compaction characteristics. In this study, attempts have been made to use modified plastic limit to account for the proportion of fraction less than 425 μm as a parameter to correlate with the compaction characteristics of natural soils. The proposed correlation between the compaction characteristics of natural soils with their modified plastic are going to be handy tool for construction engineers in quickly assessing their suitability for compaction related purposes.

Correlation of compaction characteristics of natural soils with modified plastic limit

Determination of undrained strength of fine-grained soils by means of SPT and its application in Turkey

For successful designs of geotechnical structures, rational determination of the engineering properties of soils is an important process. In this context, compaction parameters, maximum dry unit we...

Estimating compaction behavior of fine-grained soils based on compaction energy

In this study, correlations were obtained between standard penetration test (SPT) and pressuremeter data measured during an extensive geotechnical investigation conducted in Istanbul, Turkey. In this context, SPT blow counts (N) were correlated with pressuremeter modulus (E
 PMT) and limit pressure (p
 L). Empirical equations were proposed to estimate limit pressure from pressuremeter modulus, and E
 PMT/p
 L ratios were calculated and evaluated. An attempt was also made to correlate limit pressure to undrained shear strength (s
 u) measured by unconfined compression strength test. Correlations were carried out for sandy and clayey soils separately. The quantity (total of 182) and quality of the data (use of same equipment and procedures during data acquisition in a well defined geological setting) mean the obtained correlations may be valuable for similar soils. It is anticipated that the correlations obtained may help designers in evaluating, comparing, interpreting or cross checking the soil parameters obtained from these two important in situ tests.

https://link.springer.com/content/pdf/10.1007/s10064-009-0248-4

Correlation of standard penetration test and pressuremeter data: a case study from Istanbul, Turkey

Many studies were performed to investigate the effect of the thickness of clay layer on the secondary compression. To find the stress-strain behavior of a tall specimen in the laboratory we have to face the major problem of friction. Without knowing the friction, the data obtained from the high specimen is not easy to interpret. The goal of the present paper is to explain the adoption of a new oedometer cell to measure frictional effects between the consolidation ring and specimen. It is observed that the side friction does not remain constant during the test and slightly increased with time at a decreasing rate. The amount of the side friction depends upon the level of the applied vertical consolidation stress on the specimen. Friction is found to be most significant at low stresses where the clay is still overconsolidated.

Ergun Togrol

Papers

Determination of undrained strength of fine-grained soils by means of SPT and its application in Turkey

Estimating compaction behavior of fine-grained soils based on compaction energy

Correlation of standard penetration test and pressuremeter data: a case study from Istanbul, Turkey

Measurement of side friction between specimen and consolidation ring with newly designed oedometer cell