The shear strength of soils

The shear strength of flawsIntroductionThe shear strength of soils is essential for any kind of stability analysis. Therefore, it is important to determine reliable values. For this mapping triaxial examens argon most appropriate. Nevertheless, direct shear tests are mostly performed to determine the shear strength of soils.From the tests result a clearer picture of the soil strata, there exit be run Shear hear where the data laughingstock be interpreted and correlated info soil parameters. The soil parameters will be intentional accordingly to the characteristic of the soil at the site itself. This causa study is about evaluating contamination for the specific site. It involves the interpretation and manipulation of data from the Shear test and chemical tests. The whole process will be determination of contamination and measure its effect on the soil and then propose some cure practices and methods.Part (1) brands ContaminantsSoils are categorized according to the contami nants present (type and amount)Soils that ascertain contaminants below regulatory concernSoils that contain high- encounter xeroxNon-hazardous1. HazardousSoil that contains hazardous waste moldiness be managed as such when contamination is above the nonhazardous waste limits or is otherwise classified a hazardous waste. The only options for soils that contain a hazardous waste are on-site remedy or off-site management as a hazardous waste.2. Non-HazardousContaminated soil is non-hazardous when two of the arriveing criteria are meta. The contaminant levels are above the most stringent soil cleanup criteria establish by NJDEP.b. The waste is not classified as a hazardous waste.3. Soils That Contain Contaminants Below Regulatory ConcernSoils that contain contaminants at levels that are below the most stringent site cleanup levels established by NJDEP for a specific site are not of regulatory concern with the exception of sites in the Pinelands Area Brownfield sites come in all sizes and shapesThe Brownfield police created four different cleanup tracks. Cleanup levels at these tracks are based, in whole or in part, upon the sites future anticipated use. A site to be used for industrial purposes, for instance, would not devour to be cleaned up as much as a site intended for commercial use. (See Appendix A for a description of each of the tracks).Clesn UpSite cleanups can be conducted by federal, state, or local government agencies and/or their contractors, by private parties accountable for the discharge of the hazardous substances, or by purchasers of land who did not cause the contamination but are willing to pay for and conduct the cleanup. Private parties can be directed by DEP to conduct cleanups or individuals can come to the department voluntarily and offer to do part of or all of a cleanup.Cleanups can be conducted to allow for any future use of the land from residences, schools, and day care centers to commercial buildings, or new industrial use s. Cleanups can excessively be conducted to turn formerly contaminated sites into parkland for passive and/or active recreation. The level of cleanup required to protect human beings health and the environment is determined by the end use envisi matchlessd for the property. Obviously, cleanup to more stringent standards is required when people will be living on the property, or when sensitive populations such as children will be using the property for schools or recreation. Protectiveness can be obtained by either totally removing the contaminants of concern, or by embraceing them, or by limiting access to the substances by creating barriers to contact, such as with soil or other types of capping material.Certain cleanups can be conducted at risk by private individuals, with little oversight by the state. However, cleanups involving ground and surface waters must be conducted with DEPs oversight because the state is the trustee for those natural resources. more or less parties conducting therapeutic will come to DEP for oversight if they desire a No Further Action (NFA) letter at the end of the process. That letter certifies that the states regulations get under ones skin been met as of a specific date, as described specifically in the letter. With the NFA comes a Covenant Not to Sue, which defines those parties who are no longer liable to conduct superfluous cleanup at the site.Part (2) Direct Shear TestA. Shear StrengthIn the Mohr-Coulomb theory of failure, shear strength has two componentsone for intact strength due to bonds or attractive forces between particles,the other produced by frictional resistance to shearing movement The shear strength of cohesivenessless soils is limited to the frictional component.When the direct shear test is used to investigate a cohesionless soil, successivetests with increasing normal stress will establish a straight reap that passes through the origin. The travel of inclination of the line with respect to the hor izontal axis is the angle of internal friction.Values of the angle of internal friction are attached in the following table. If the soil is dense when tested, initially higher values for the angle of internal friction will be measured, but with increasing amounts of strain, the angle will decline to the approximate ranges seen in the Table.SOIL TYPEANGLE , DEGREESSand and gravel mixture33 36Well-graded sand32 35Fine to medium sand29 32Silty sand27 32Silt (non-plastic)26 30The shear strength of a cohesive soil is more complicated than a cohesionless material. The differences are due to the role of pore water in a cohesive soil. Most cohesive soils in field conditions are at or near saturation because of their tendency to switch moisture and their low permeability.When load is applied to a soil of this type, the load is supported by an increase inthe pore-water pressure until pore-water can drain into regions of lower pressure.At that point, soil particles are forced closer in concert and the strength increases,just like a cohesionless soil. Time is an important factor however, because it takes longer for water to move out of a low permeability material.Direct Shear TestResults of the direct shear tests should be evaluated statistically. The statistical assessment in the shear shock test includes the values of friction angle () and cohesion (c), derived from the Mohr-Coulomb regression line, and the (original) measured values of peak shear strength. In previous publications only the derived parameters and c were taken into account. As the most important result the investigations have shown that it devotes a remarkable difference whether the pair of variables and c or peak shear strength is considered.http//www.csus.edu/indiv/c/cornwell/engineering/9-20-06.pdfDirect Shear Box Test Procedure1. Bring the shear box togetherhttp//www.civil.mrt.ac.lk/docs/direct_shear_test2. Compact the soil sample (which has reached the optimum moisture content) in the mo uld.3. Place the sample into the shear box4. Record the weight of the applied load and place the loading plate on top of the upper porous platehttp//www.civil.mrt.ac.lk/docs/direct_shear_test5. Remove the alignment screws to hold the shear box together.6. Tighten the diagonally opposite screws to reduce the frictional force.7. Reset the dial gauges.7. Apply the normal load.8. Start the motor to produce the desire constant rate of shearing9. Take readings from the gauges,a) Proving ring.b) Horizontal displacement.c) Vertical displacement.10. When the shear load starts to reduce or remains constant stop the testhttp//www.civil.mrt.ac.lk/docs/direct_shear_testA. selective informationProving ringHorizontal(0.001 in)VerticalTime09.000.00000059.110.000030159.120.00010015.59.260.00013018.59.380.000200209.630.000300229.870.0004002310.120.0005002410.360.0006002310.620.0007002410.870.0008002611.120.0009002511.370.0010002611.620.0011002711.870.0012002712.120.00130027.512.370.0014002812.620.00 15002812.870.0016002913.110.0017002813.370.0018003113.620.00190029.513.870.002000ResultsShear stress KpaHorizontal(0.001 in)Time0.0009.0000000.9519.1100302.8629.1201002.9509.2601303.5289.3802003.8129.6303004.1949.8704004.38110.1205004.57710.3606004.38110.6207004.57710.8708004.95911.1209004.76311.3710004.95911.6211005.14511.8712005.14512.1213005.24312.3714005.33112.6215005.33112.8716005.52713.1117005.33113.3718005.52713.6219005.62513.872000FAILUER = 5.527 kpa.Part (3) Contamination AssessmentPH MeasurementsPH measurements were measured against toxic shock syndrome results, While no apparent correlation was found between pH and salinity samples presenting higher pH generally had higher TSS concentrations, as indicated in the figure below. The addition of cement (and its effect on turbidity) appears to have had a noticeable effect on pH.In addition to the various testing that was performed as part of this study, two additional studies beyond the original scope were conducted(a) an eva luation of the effect that organic content found within silt alluviations would have on soil-cement hydration and strength gain, and(b) an assessment of whether the cement stabilization/ straightforwardification of contaminated depositions immobilizes organic and inorganic contaminants within the sediment.Part (4) Remediation. Chemical Fixation And SolidificationTaking into devotion to select the best fit remediation method and conserve ecosystem and trying not to undergo major landscape disruption.One alternative to dredging and disposing of contaminated sediment is to solidify the sediment in-situ using CDSM, and cover the stabilized sediment with a cap. In this scenario, the mixing is a viable way to reduce the say-so for highly contaminated sediments to be eroded over term by natural hydrologic events, vessel traffic or dredging.In situations where decisions regarding removal of sediment have not yet been made or if management alternatives (decontamination) are not yet full y developed, the CDSM technology can be used to stabilize sediment for later removal.Chemical fixation and Solidification, CFS, also commonly referred to as Solidification/Stabilization Treatment, S/S, is a widely used treatment for the management of a broad range of wastes, especially those classified as hazardous. The initial application of the technology in the United States dates back to the 1950s when it was fruitfully used to treat and dispose of radioactive waste.The USEPA considers S/S an established treatment technology, and has identified it as the best demonstrated available technology, BDAT, for 57 RCRA-listed wastes. It is anticipated that 30% of the CERCLA (Superfund) remediation sites include the use of S/S.There is an ample body of technical literature that documents the fundamentals for applying S/S, as well as the practical companionship using the technology in a wide variety of wastes, contaminants and chemical matrices. The applicability of using S/S to immobili ze the principal contaminants in the Passaic River sediments was evaluated.The following sections briefly summarize those findings.There are several additives mentioned in the literature as potential enhancers of the PCB immobilization. These depend on the particular conditions of the application1. Organically limited clays2. Activated carbon3. Ferric hydroxide4. Rubber particulateA well-documented case where S/S was used for the immobilization of PCBs in contaminated soils is provided in the Yellow Water Road Dump in Duval County, Florida. Where In that case, a superfund site that started remedial action in 1984 was removed from the NPL in 1999. During the remedial activities, 4472 blockish yards of PCB contaminated soils were excavated and treated with S/S and placed back within the former operations area of the site.A groundwater monitoring program was established, and monitoring well were installed to evaluate the future need for contingent pump-and-treat remedy. The site was m onitored as part of the EPA five-year review program. In September 2000, the five-year-review report established that the selected remedy remained protective of human health and the environment. Site inspections and groundwater monitoring continue to ensure long-term protectiveness.Out-Of-State RecyclingFor recycling soils out-of-state, a written determination from NJDEP is required as to the non-applicability of the solid waste management regulations set forth in N.J.A.C. 726-1 et seq. For sites without a Site Remediation Program lead (i.e., Industrial Site Recovery Act, Bureau of resistance Storage Tanks, Bureau of Field Operations) and for the recycling of soil as a solid process waste, contact the Bureau of Resource Recovery and Technical Programs (609/984-6985).Sites with a Site Remediation Program lead must send this information in lieu of a Soil Reuse Proposal to the assigned case manager for an approval. The following are the standard requirements pursuant to (N.J.A.C. 726-1 ) for approval to send soils out-of-statea. A letter, sent to the Bureau of Resource Recovery and Technical Programs from the writer of soil, certifying that the soil in question has been analyzed or is known in accordance with N.J.A.C. 726G-5.1 not to contain a hazardous waste. This also must include any necessary test results documenting that the soil contains constituents and hazardous waste characteristics below their regulatory levels.b. A letter sent to the Solid and Hazardous dash off Division from the receiving a facility stating that they agree to accept the specified amount of soil, indicating intention and method to beneficially use or reuse the soil and the succession frame for such activity from the date of receipt at the facility.In addition, a repeat of this information must be sent directly to the solid waste coordinator of the county of the soils origin.c. A letter sent to the Solid and Hazardous go down on Division from the proper regulatory agency of the rece iving state or a copy of a current facility permit verifying that facility is operating in accordance with applicable rules and regulations and can accept the soils for the declared use/reuse.d. at one time the soil is delivered to the identified use/reuse facility, a letter from the facility or a bill of lading stating the date and amount of soil current must be sent to Solid and Hazardous Waste Division and the solid waste coordinator of the county of the soils origin.Operational Landfill CoverOperating landfills that are permitted to accept ID 27 waste may use non-hazardous soil for daily landfill cover with approval from the Bureau of Landfill and Recycling Management. Fine grained soils which may create erosion problems or are easily windblown are prohibited for use as daily cover.Brownfield sites are found in both urban and rural settings and the present challenges that make the cleanup and redevelopment of these sites unique as compared with other real estate projects.Brown field sites deal with four key issues, includingEnvironmental Liability Developers, land owners, and prospective associated with the propertys floor can be prosperingly addressed.Financial Barriers Private financial institutions or investors may be reluctant to provide loans for sites impacted by real or perceived environmental contamination.Cleanup Activities Redeveloping a brownfield site may take longer than that of a typical real estate development if remediation is warranted. practicable Reuse A viable plan for putting the site back into productive use based upon the localitys goals and well researched information are critical to successful redevelopment.Despite these challenges significant opportunities exist for brownfield redevelopment which can economically revitalize an area and improve the quality of life for communities.Brownfield redevelopment is also an ideal time to integrate a number of sustainability features that can result in improved storm water management, reduced air emissions and energy consumption, and preserve the history and civilisation of our communities.The purpose of this guide is to provide a starting point for information about brownfield redevelopment planning, regulatory considerations and resources available from the federal Environmental Protection situation (EPA) and the Iowa Departments of Economic Development and Natural Resources.6. References1- NJDEP. Discussion Paper on Landfill Closure and Remediation Issues.(1993).2- Environmental Protection Agency. Handbook for Remedial Action at Waste Disposal Sites.3- Bujang B.K. Huat et al., (2007) Modified shear box test apparatus for measuring shear strength of unsaturated residual soil , Faisal Hj. Ali, S.Hashim , Thomson Gale (December 27, 2007)4- Marcel van der Perk, (2009), Soil and Water Contamination From Molecular to Catchment Scale, TF Books UK 1 edition (January 28, 2009)Appendix ADescription Of The Brownfield Cleanup footstepsThe statute establishes four diff erent tracks that a developer can follow in remediating a site. low address 1, a remedial program shall achieve a cleanup level that will allow the site to be used for any purpose without restriction and without reliance on the long-term concern of institutional or engineering controls. ECL 27-1415(4). With respect to soil remediation, the statute directs that Track 1 cleanups shall achieve the generic SCOs designed to allow for unrestricted future use of the property. Id. A developer who remediates a site to Track 1 standards receives a greater tax credit than is available for remediation under the other three tracks.Under Track 2, a remedial program may include restrictions on the use of the site or reliance on the long-term employment of engineering and/or institutional controls. ECL 27-1415(4). With respect to soil remediation, however, the statute directs that a Track 2 cleanup shall achieve the generic SCOs appropriate for the future use of the property without the use of in stitutional or engineering controls to reach such objectives. Id.Under Track 3, the developer does not need to achieve the generic SCOs, but instead may use site specific data to determine soil remediation objectives. ECL 27- 1415(4). Those sitespecific objectives must conform with the criteria used to develop the generic SCOs. Id. Like the generic SCOs, soil remediation objectives developed by the applicant pursuant to Track 3 shall not exceed an excess cancer risk of one in one million for carcinogenic end points and a hazard index of one for non-cancer end points, except where rural soil background contamination exceeds that risk level. ECL 27-1415(6)(b).A Track 4 remedial program shall achieve a cleanup level that will be protective for the sites current, intended or reasonably anticipated residential, commercial, or industrial use with restrictions and with reliance on the long-term employment of institutional or engineering controls to achieve such level. ECL 27-1415(4). The s tatute instructs that for Track 4, exposed surface soils shall not exceed the generic contaminant-specific SCOs developed for unrestricted, commercial, or industrial use pursuant to this subdivision which conforms with the sites current intended, or reasonably anticipated future use. ECL 27-1415(6)(d). The statute defines exposed surface soils as two feet for sites used for residential use and one foot for