Category: Civil Projects

During the course of site investigation, different penetration tests are carried out and these tests are enlisted below: Standard Penetration Test (SPT), Dynamic Cone Penetration Test (DCPT) and Static Cone penetration Test (CPT). Among these, Standard penetration test SPT is the most popular one and is widely used. Standard penetration test: The test is conducted by driving a split spoon (Fig 1  c) into the soil for a distance of 450 mm. The force required to drive the spoon up to that depth is provided by a standard hammer of…

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What are the types of sampler? Usually there are two common types of sampler; thin walled Shelby Tubes or Piston Samplers. Besides these, there are some other types of samplers and they are: open drive samplers and split spoon samplers. These samplers are shown in Fig.1.   Shelby Tube | Types of sampler The thin walled seamless steel tubes are called Shelby tubes. They are generally used to take undisturbed samples for routine site investigation works. The clear sketch of Shelby tube is shown in Fig.2.6 (a). The tube is…

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What are the requirement of sampling? In this article we will discuss about different requirement of sampling. Area Ratio – It is the degree of disturbance. In general terms, Area Ratio can be defined as a ratio of annular cross sectional area of the tube to the area of the sample. Mathematically, it is expressed as: Where, Ar = Area ratio Do = Outside diameter of the tube Di = Inside diameter of the tube Usually, most code specifies that the area ratio should not exceed 25 %, it is…

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What is Sampling and Sampling Procedure? The process of extraction of soil samples from drilling tools and sampling equipment is known as sampling and sampling procedure. Two types of samples are taken during the site investigation and they are: Disturbed Samples Undisturbed Samples Disturbed samples Disturbed samples can be further classified as: Representative samples Non-representative samples In case of disturbed samples the soil loses its original form or we can say the structural configuration of soil is changed or destroyed. During the standard penetration test of the sampling process, the…

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What is Rotary Drilling or Open Hole Core Drilling? During site investigation, drilling in rocks is very important step to produce continuous core. The strength, condition and sequence of the rocks, which will support the loading’s, must be set properly by appropriate examination and testing. These days, the loading’s are transmitted to the foundations. Different processes like construction of large dams, tunnels and presence of voids below a site often call for the drilling process through rocks. Out of other drilling processes, rotary drilling is undeniably the most expensive type…

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As shown clearly in the figure 1, the percussion drilling method involves a heavy drilling bit in the form of a chisel or a clay cutter, attached to the end of a cable operated by a Winch of the drilling machine. Percussion boring rig Boring tools and chisel Shell Clay cutter That drilling bit is called a chopping bit. During the drilling process, the bit or cutter is lowered or raised in the borehole and in order to break the soil into fragments, water is added. The amount of water…

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Introduction to Wash Boring, Setup of Wash Boring and its techniques: The technique of wash boring involves a simple process of developing a considerable deep borehole into the ground as clearly illustrated in the figure 1. In this article we will also discuss about setup of wash boring. In wash boring process, a piece of casing with a diameter about 50 to 100 mm and to a depth of 1.5 m to 3.0 m is directly driven into the ground. The casing is provided with a chopping bit fastened on…

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What is Auger Boring and how Borehole is made using hand auger? Operations like boring doesn’t allow direct access to the subsoil and holes are bored into the ground by hand or power arguers and etc. Practically, auger boring is a device or an instrument as we say in general language which supports us in developing a borehole into the ground. In the market, different power operated and hand operated augers can be found. Among them, two types of hand operated augers; post-hole type and helical type have been clearly…

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