DETAIL SOIL INVESTIGATION

INTRODUCTION
SOIL INVESTIGATION is carried out to design a right type of foundation safely and economically. A designer requires adequate information about the physical properties and the arrangement of the materials underground. The field and laboratory investigations needed to get this necessary information is known as soil exploration. The study of complete soil investigations can be grouped as follows : • Objectives or purposes, • Preliminary investigations, • Methods of site exploration, • Depth and spacing of trial pits and bore holes, • Choice of a method, • Recording of data.
The investigation of the geology and previous uses of any site, together with the determination of its engineering, environmental and contamination characteristics is fundamental to both safe and economic development.
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SOIL TESTING • Soil tests can be conducted on samples that truly represent the soil at the site. • Soil sampling, testing and test interpretation must be conducted with guidance from specially trained and experienced personnel. • Proper soil testing is proven to be a reliable basis for the design of foundations and commonly used in site investigations to indicate their potential use and limitations. • Based on the premise that the behavior of soil masses under imposed conditions can be predicted if certain soil properties can be measured. • The results of soil tests must be interpreted based on past experience, climate and the geology of the site. • Most important requirements is that design of many notable structures on difficult sites.
GEONAMICS is a specialist company that can provide guidance and management of the investigation process through all phases of study, ground investigation, testing and design. Methods range from non-intrusive geophysics through to fully intrusive borehole. The method depends on parameters such as depth, soil type and access to the site It is common for investigations to be phased – allowing the results of the early phases to guide the next stages
TYPES OF SOIL • IN-SITU TESTING • TRIAL PITTING • DYNAMICS PROBE TEST • BOREHOLES

IN-SITU TESTING
In-situ testing techniques including Standard Penetration Testing, Permeability Testing, Borehole Vane Testing, Pressure meter Testing and Packer Testing can all be carried out in the boreholes in order to provide information for geotechnical design. Disturbed and undisturbed samples are retrieved from the boreholes for inspection and logging by engineers and subsequent testing in our laboratories.
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TRIAL PITTING
Trial pitting can be carried out by a variety of methods from hand dug pits to machine excavated trenches. Trial pitting is generally carried out to a maximum depth of 4.5m with standard excavation plant and, depending on soil conditions, is generally suitable for most low rise developments. All trial pit investigations are supervised by experienced engineers with a thorough understanding of geology and soil mechanics.
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DYNAMICS PROBE TEST

Cone Penetration Test
To carried out the cone penetration test is pushed into a soil deposit while various measured parameters are recorded. The test is similar to the Dutch Deep sounding (or piezocone test) with the addition of a cone penetration element in the probe to measure water pressure. The test is also known as pore pressure sounding or CPTU.
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Mackintosh/JKR Probe Test
This is a dynamic penetrometer test used to check the consistency of the subsoil. Mackintosh Probe which has 30° cone penetrometer while JKR Probes has 60° cone penetrometer. This is a light dynamic test and the cone is driven directly into the soil by driving a hammer 5 kg. Weight dropping through a free height of 280mm. The probe is unable to penetrate into medium strength soil and gravelly ground.
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BOREHOLES
A borehole is used to determine the nature of the ground (usually below 6m depth) in a qualitative manner and then recover undisturbed samples for quantitative examination. Where this is not possible, for in gravelly soils below the water table, in-situ testing methods are used. Obviously the information gained from a borehole is an extremely limited picture of the subsurface structure. It is there fore essential to compare the results obtained with those that could have been expected from the desk study. the greater number of boreholes the more certain it is possible to be of the correlation and thus to trust in the results.

Rotary Drilled Boreholl
Rotary drilling techniques are employed where boreholes are required into soil or bedrock. This utilises a rotary drilling to advance a hole into the ground. Soil samples are collected from a core device from the centre of the drill stem. The choice of drilling equipment depends on ground conditions. Equipment varies from a relatively compact (2m x 1m x 2m high) self powered rig. Rotary drilling is particularly useful in difficult ground conditions or when rock coring is required.
Rotary drilling borehole are used on land and on coastal areas.
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Cable Percussive Borehole

The minimum diameter of hand auger boring is 100mm and casing not be required. It was advanced by hand auger tool, Hand Augers may be used for any proposed where disturbed sample are satisfactory and are valuable in advancing holes to a depth at which disturbed sampling are required.
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HAND AUGER
A large (4m x 4m x 7m high) percussion rig that drives a cutting or collecting instrument (dependent on ground conditions) into the ground, to collect soil that is then removed and sampled. This can be a slow technique however the advantage is that the hole can be cased to prevent collapse in loose soil layers, allowing easy installation of groundwater sampling pipework. It is highly adaptable to, and designed for, geotechnical testing.
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LABORATORY TEST FOR SOIL

Atterberg limits
The Atterberg limits define the boundaries of several states of consistency for plastic soils. The boundaries are defined by the amount of water a soil needs to be at one of those boundaries. The boundaries are called the plastic limit and the liquid limit, and the difference between them is called the plasticity index. The shrinkage limit is also a part of the Atterberg limits.
Water Content
This test provides the water content of the soil, normally expressed as a percentage of the weight of water to the dry weight of the soil.

If your Stage 2 investigation reveals that contaminated land exists on your property, it's time for a Detailed Site Investigation to find out the exact extent. This process can be expensive if your consultant doesn't know what they're doing. Avoid that risk by hiring NEXT Environmental.

With our skills and seasoned judgment, we can help you minimize costs while getting the data you need to quantify the contamination. As the final investigative step prior to enlisting environmental remediation services, a properly executed DSI can help you evaluate your options and find the best solution for your needs.

As with all of our services, we work hard to ensure you're informed at every step, and can understand our reports completely.
In-situ tests are an essential part of all ground improvement projects and may be needed during several phases of a compaction project, as discussed above:

• during the planning phase of a project for establishing of geotechnical conditions, • during the design phase for selection of appropriate compaction method, • during a trial phase for evaluation of compaction procedure and verification of compaction effect, • during the production phase for production control and verification of compaction effect, and • after completion of the project for documentation of long-term performance.

A variety of techniques, tests and observations can yield useful information regarding the effectiveness of deep soil compaction, Mitchell (1986). Visual observations of the compaction process, of soil response and of the performance of compaction equipment on site can provide a valuable background for the planning and implementation of more detailed geotechnical investigations. The compaction effectiveness can also be monitored indirectly by recording machine performance data, using electronic sensors attached to different components of the compaction equipment. These aspects will be discussed in more detail below.
However, different types of penetrometers are most frequently used for compaction projects. During the exploratory phase of a soil investigation it is possible to determine the soil conditions in general such as the depth, thickness and lateral extent of the various strata. They can also be used to check the density of fills and to estimate the compressibility and shear strength of primarily granular soils. A variety of different static and dynamic penetrometers are used today. The most advanced sounding method today is the Cone Penetration Test (CPT), which has become very popular in Europe and in the Far East and in some parts of North America. In the United States and in many other parts of the world the Standard Penetration Test (SPT) is still used extensively, primarily due to familiarity and experience of test interpretation with this method.
The CPT and SPT have been standardised by the International Society for Soil Mechanics and Foundation Engineering (ISSMFE). National standards also exist in different countries.
Deformation properties (modulus values) can be determined in the laboratory on disturbed, reconstituted samples. The main problem in granular soils is the difficulty and high cost to obtain undisturbed soil samples. Therefore, different types of field investigation methods are used at most compaction projects. Empirical correlation of deformation characteristics and stress conditions with in situ tests, such as the Menard pressuremeter (PMT), the Machetti flat dilatometer (DMT) or seismic tests have been developed, Belotti et al. (1986). In the following section, the most important field investigation methods for compaction control will be discussed.General resourse information is typically prepared at a scale sufficient to broadly characterize an area.For example,the USDA soil delineation maps identify major soil series that main contain small areas that differ in physical properties. If these differing properties could impact the design or function of the planned improvements, their precise location needs to be determined through a detialed site-specicific investigation. Geotechnical explorations are conducted ti identify subsurface conditions and to gather samples for laboratory testing when the structural designer needs data. After review of the detailed investigation, the conceptual site plan is often refined ti improve its feasibility. Structure locations may be adjusted or roadways realigned to better fit site conditions.