Table of Contents
What do you understand by bore log?
A record, made by the driller or geologist, of the rocks penetrated in the borehole. In the laboratory, a more detailed log is prepared giving particulars relating to lithology, paleontology, water analysis, etc.
What is the n value in borehole log?
The sum of the second and third interval (i.e. 6 inches to 12 inches and 12 inches to 18 inches) provides the Standard Penetration Resistance (N). In this example, the N-value is 16 blows per foot. Computer generated logs often provide a plot of the N-value with depth as shown within the green circled area.
How do you determine boring depth?
32.3 Minimum depth of boring (ASCE, 1972) Determine the depth D = D2, at which Δσ/ σ’v = 0.05. Unless bedrock is encountered, the smaller of the two depths, D1 and D2 will be the approximate minimum depth of boring required.
What is SPT N value?
SPT N value is widely used as it is an index for quick strength characterization due to its simplicity. In estimation of other parameters also, SPT N value is used e.g., for estimation of shear wave velocity, bearing capacity etc. The SPT field test is most conventional test for general characterization of soil.
What is a borehole test?
A borehole pump test is a controlled experiment in which a borehole is pumped at a controlled rate and water-level response (draw-down) is measured. A yield test on a spring can vary from a basic bucket test to more prolonged monitoring.
What is bore log chart?
A borehole log is a record or graph of the sensor output (e.g., gamma ray count rate) plotted on the horizontal axis versus depth on the vertical axis.
What are borehole logs used for?
The aim of borehole logging is to create a record of the in situ ground conditions. However, the recovery of material from the ground for inspection at the surface can result in disturbance of the materials, the degree of which will depend on the material type and the drilling method.
What are the different types of well logging?
Well Log Techniques Acoustic Logs. Cement Bond Log. Cross-Dipole Acoustic Log. Caliper Log. Chemical Logging. Density Log. Gamma Log. Image Logs. Mud Logging. Neutron Log.
What is SPT number?
Standard Penetration Test (SPT) is a simple and low-cost testing procedure widely used in geotechnical investigation to determine the relative density and angle of shearing resistance of cohesionless soils and also the strength of stiff cohesive soils.
What does N value mean?
n-value, also known as the strain hardening exponent, is the measure of a metal’s response to cold working. Cold working is the plastic deformation of metal below its recrystallization temperature and this is used in many manufacturing processes, such as wire drawing, forging and rolling.
How do you calculate SPT?
Step: 1 Take Average of Penetration Value. Step: 2 Find our Angle of Shearing Resistance. Step: 3 Find out Effective Surcharge. Step: 4 Find out Bearing Capacity Factor. Step: 5 Find Out Shape Factor. Step: 6 Find Out Depth Factor. Step: 7 Calculate Inclination Factor. Step: 8 Calculate Correction Factor.
What is depth of boring?
Introduction to Depth of Boring: At the depth equal to two times the width of foundation, this stress is about 10%. Considering the effect of stress felt, the boring should be always taken to a depth at least equal to one and half times of the foundation width below the base of the foundation.
What is the maximum depth of Borewell?
The deepest known borewells in Bangalore now are at depths of over 1700 feet. Shallower ones exist at 100 feet. In Bangalore’s geology, deep aquifers start in most places at depth of about 100 feet, in the hard rock layer.
What is spacing of boring?
The distance between boreholes drilled for exploration or sampling purposes. With bedded minerals, the holes may be positioned at the intersection points of coordinates or at the corners of equilateral triangles with sides from 30 to 200 m apart. The spacing is closer with patchy deposits.
What means SPT?
The standard penetration test (SPT) is an in-situ dynamic penetration test designed to provide information on the geotechnical engineering properties of soil. The test provides samples for identification purposes and provides a measure of penetration resistance which can be used for geotechnical design purposes.
What is the difference between SPT and CPT?
Cone Penetration Testing (CPT) is fast, safe, and offers digital in situ soil behavior type (SBT) instantly. CPT data offers high resolution in situ results versus SPT, which often utilizes variable intervals and limited grab samples from various depths.
How deep can a borehole go?
Drilling a borehole for household use will usually range from about 100 feet to 500 feet deep, but when drilling a new borehole for your home or business, the depth of the well depends on the geology and underground water levels of the area.
What is the difference between borehole and well?
There is no difference between well, hole and borehole in the sense of the words. A well is a man-made hole deeper than the water table. A borehole is a narrow shaft bored in the ground, either vertically or horizontally.
Is it safe to drink borehole water?
Can I Drink The Water? In short, yes, borehole water is usually safe to drink. However, The Private Water Supplies Regulations have said that you must have your private water supply checked to ensure it is consistent with drinking water standards.
What is wash boring method?
Wash boring is a fast and simple method for advancing holes in all types of soils. The resulting chopping and jetting action of the bit and water disintegrate the soil. The cutting is forced up to the ground surface in the form of soil − water slurry through the annular space between the drill rod and the casing.
