Application Of Dynamic Penetration Test To Evaluate The Strength And Deformation Of Ground Pdf

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To determine the degree of compaction of subgrades filled with fine-grained soil, the compaction test and light dynamic penetrometer LDP test were carried out for low liquid-limit clay samples with different water contents in laboratory.

Cone penetration test

To determine the degree of compaction of subgrades filled with fine-grained soil, the compaction test and light dynamic penetrometer LDP test were carried out for low liquid-limit clay samples with different water contents in laboratory.

After that, the existing fine-grained soil subgrades on LDP-based field tests were excavated. The on-site PR values, water contents, and degrees of compaction of slopes were obtained. The estimated degrees of compaction using the prediction equation were compared with measured values of the degree of compaction in field.

The results show that there is good consistency between them, and an error within 3. In addition, the water content should be determined firstly while using the prediction equation which is proposed in this study.

Therefore, a numerical method of the water content of a subgrade was developed, and the predicted and measured water contents were compared, which shows a relatively high relativity.

Then, the degree of compaction of fine-grained soil subgrades can be calculated according to the predicting equation, which involves the penetration ratio PR and the numerically calculated water content as input instead of the measured value in the field.

In civil engineering, the investigation of the strength and integrity of every highway subgrade becomes necessary to optimize pavement structural performance and safety [ 1 ].

If the results of investigation do not meet the requirements of compaction in design, the carrying capacity of the subgrade would be lower and then some distresses would occur such as the settlement of the subgrade and the cracking of pavement [ 5 ]. Traditionally, one of the activities during the subgrade investigation is determination of degree of compaction with different field and laboratory tests such as the sand-cone method [ 6 ] and cutting ring method [ 7 , 8 ].

Although these evaluation methods are the best and reliable, they have relatively complicated steps and take much time to have the end result [ 9 ]. In addition, the soil samples in these methods need to be cored or excavated on the subgrade which is destructive and can have significant impact on pavement performance [ 10 ]. To overcome these shortcomings, many nondestructive and time-saving determination methods and equipment have been developed [ 11 — 13 ].

This device provides continuous and uninterrupted stratigraphic data when its cone probe is driven into soil along the vertical depth. The data obtained from the DCP have got a strong theoretical acceptance and can be used to comprehensively assess the foundation soil. The application of the DCP was further investigated by previous researchers.

Siekmeier et al. Mohammadi et al. The advantage of using the DCP is testing the soil properties in its natural density and moisture content state. These applications of the theory and method of the DCP have been accepted for different soils, and they provide a way to the empirical correlations based on the statistical analyses of field tests and soil properties.

Compared to the DCP, its hammer is lighter and the drop distance is shorter, which is convenient and fast for the field testing of subgrade using the LDP instead of the DCP. Therefore, the objective of this paper is to test the degree of compaction of the fine-grained soil subgrade using the LDP. First, the principles and steps of the LDP-based test were introduced.

Then, the validity of this equation was verified by the field tests of fine-grained soil subgrades. Finally, a numerical method for calculating the water content of subgrades was put forward and verified. Thus, the degree of compaction of fine-grained soil subgrades can be calculated according to the quadratic predicting equation, which uses the penetration ratio PR and the numerically calculated water content instead of the measured value in the field.

When a field test is conducted using the LDP, the depth and drops of the hammer of the LDP are recorded when the cone tip is driven into soils by the hammer. The penetration ratio PR , defined as the depth per drop of the hammer, can reflect the properties of soil layers. When a test using the LDP is conducted, the following procedure should be carried out: 1 The testing site should be flat, and a record book also should be prepared. The penetration rod should always be perpendicular to the ground surface when the test is in progress.

The hammer should be lifted and released along the penetration rod. At the same time, the penetration frequency and depth are needed to be recorded. The soil samples were taken from the Nanchang-Zhangshu expressway widening project in Jiangxi Province. The liquid limit, plastic limit, optimum moisture content, maximum dry density, and particle size analysis were conducted for soil classification and basic properties.

Their liquid limit and plastic limit are According to the compaction test, the optimum moisture content and maximum dry density are The particle size analysis shows that 0. In order to study the influence of water content on the PR measured by the LDP, different soil specimens with 5 initial water contents and 5 dry densities were prepared.

The relationships between the water content and PR with different degrees of compaction were curved in Figure 3. It can be seen in Figure 3 that the minimum PR value is found nearby the optimum water content for the same degree of compaction, and the PR values decrease with the increasing degree of compaction values for the same water content.

As mentioned above, the penetration ratio PR of the LDP can reflect the density properties of soil layers. The light dynamic penetrometer LDP tests were carried out from the top of 96 zone i. Figure 5 shows the PR values of different testing programs. The reason is that the LDP-based field test was conducted in summer, and the water contents of slope surface were relatively low.

It shows that there is no obvious difference in properties of the subgrade within this scope in spite of the fact that their initial degrees of compaction are different. Also, Figure 5 shows that the PR values of V3 section are larger than those of the other two sections, which indicates that the water contents of the bottom subgrade are larger than those of the top subgrade.

The lowest horizontal plane is on the bottom of the ditch. Their average values were taken as the final values for this location. Figure 7 shows the measured water contents and degrees of compaction.

This is because the water content for the top depth is controlled by the climate and that for the bottom depth is controlled by the ground water. The former changes sharply for different seasons, while the latter is stable with seasonal changes. The estimated degrees of compaction using 1 and the measured values are shown in Figure 8. It can be seen in Figure 8 that they are relatively consistent. The root mean square errors between the estimated and measured degrees of compaction at V1, V2, and V3 vertical sections are 3.

Therefore, the differences between the estimated and measured degrees of compaction are acceptable, which means that the predicting equation of degrees of compaction based on the PR and water content has a satisfactory accuracy. According to the above research, the degree of compaction of subgrade slope soil at different depths can be calculated based on the PR value and the measured water content.

The former can be gained quickly using the LDP, and the latter is time consuming. Therefore, a rapid method to determine the water content is the key to calculate the degree of compaction using 1. The water content of subgrade slope soil can be calculated using the numerical simulation, which is proved to be rational by some researchers using the GeoStudio software [ 22 — 25 ]. This simulation needs some parameters including the hydraulic properties, thermodynamic properties, physiological parameters, and meteorological parameters of soils.

All the needed parameters are shown in Table 1. Their values can be referred to the literature [ 22 ]. Water content was calculated using the parameters mentioned above, and the results of calculated water content values of soil are shown in Figure 9. It can be seen in Figure 9 that the calculated and measured water contents of V1, V2, and V3 sections show a good coincidence in general.

Due to the inhomogeneity of the subgrade and the measured errors, some data are scattered. Besides the discrete points, the root mean square errors between the measured and calculated water contents of V1, V2, and V3 sections are 1.

It shows a relatively high accuracy for engineering practices. Therefore, the water content of the subgrade in different depths can be calculated using the numerical method. Furthermore, to investigate the accuracy of the degrees of compaction from 1 using the calculated and measured water contents, they are shown in Figure It can be seen from Figure 10 that the estimated degrees of compaction of the subgrade based on the numerical water content, in general, do not deviate from the measured values significantly.

Due to the inhomogeneity of the subgrade and the measured errors, some test points are scattered. Besides three discrete points, the root mean square errors between the estimated and measured degrees of compaction are 2.

It shows that, for an existing subgrade, these degrees of compaction estimated by 1 according to the numerical and measured water contents are almost equivalent.

Since the water content of any depth in subgrades can be determined using the numerical method in this study without excavating the subgrade slopes, which is much more time-saving than the measurement in the field, the PR and numerical water content can be used to predict the degree of compaction using 1 quickly. The compaction test and light dynamic penetrometer LDP tests were carried out for low liquid-limit clay samples with different water contents in laboratory.

In order to avoid excavating the subgrade slope to measure its water content, a numerical method to determine the water content of a subgrade slope was put forward. It can be utilized to substitute the measured water content. Some major conclusions may be drawn as follows: 1 A quadratic function between the degree of compaction, PR, and water content measured of low liquid-limit clay was established and verified.

The root mean square error between the estimated and measured degrees of compaction was within 3. A numerical method of water content for subgrade slope soils was proposed and verified. The results show that they have a relatively satisfactory accuracy.

Therefore, this numerical method can be utilized to calculate the water content in subgrades, which is much more time saving than the on-site measurement.

This method was proved to be rational by comparing the calculated and measured water contents. The data used to support the findings of this study are available from the corresponding author upon request. This is an open access article distributed under the Creative Commons Attribution License , which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Journal overview.

Special Issues. Academic Editor: Qiang Tang. Received 27 Feb Revised 29 Apr Accepted 26 May Published 12 Jul Abstract To determine the degree of compaction of subgrades filled with fine-grained soil, the compaction test and light dynamic penetrometer LDP test were carried out for low liquid-limit clay samples with different water contents in laboratory. Introduction In civil engineering, the investigation of the strength and integrity of every highway subgrade becomes necessary to optimize pavement structural performance and safety [ 1 ].

Figure 1. Figure 2. Figure 3. Figure 4.

Measurement of Degree of Compaction of Fine-Grained Soil Subgrade Using Light Dynamic Penetrometer

This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by July , and conflicting national standards shall be withdrawn at the latest by July This document specifies requirements for indirect investigations of soil by standard penetration test as part of geotechnical investigation and testing according to EN and EN to compliment direct investigations e. The standard penetration test aims to determine the resistance of soils at the base of a borehole to the dynamic penetration of a split barrel sampler and the recovering of disturbed samples for identification purposes SPT. In gravelly soils and in soft rocks a solid cone is also be used SPT C. The standard penetration test is used mainly to assess the strength and deformation parameters of cohesionless soils, but some valuable data may also be obtained in other soil types. The following referenced documents are indispensable for the application of this document.

The standard penetration test SPT is an in-situ dynamic penetration test designed to provide information on the geotechnical engineering properties of soil. This test is the most frequently used subsurface exploration drilling test performed worldwide. The test provides samples for identification purposes and provides a measure of penetration resistance which can be used for geotechnical design purposes. Many local and widely published international correlations which relate blow count, or N-value, to the engineering properties of soils are available for geotechnical engineering purposes. The test uses a thick-walled sample tube, with an outside diameter of

Dynamic cone penetration DCP is a field test that is used as a substitute for other penetration tests because it is portable, low cost, quick and simple to use. However, the effect of skin friction can significantly influence the accuracy of the test results. The current study investigated the effect of skin friction through field testing on silt and fine sand deposits. The tests were initially conducted at different energy levels using seven cones with different geometries. The optimal cone was selected after ascertaining the repeatability of the test results. The effect of soil collapse around the rods, as an important factor causing error in the results, was addressed by recording the torsion and developing a correction coefficient. Finally, the model was verified at different sites featuring silty sand sediment where the predicted values showed good compliance with the measured DCPT results.

Measurement of Degree of Compaction of Fine-Grained Soil Subgrade Using Light Dynamic Penetrometer

This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by July , and conflicting national standards shall be withdrawn at the latest by July This document specifies requirements for indirect investigations of soil by standard penetration test as part of geotechnical investigation and testing according to EN and EN to compliment direct investigations e. The standard penetration test aims to determine the resistance of soils at the base of a borehole to the dynamic penetration of a split barrel sampler and the recovering of disturbed samples for identification purposes SPT. In gravelly soils and in soft rocks a solid cone is also be used SPT C. The standard penetration test is used mainly to assess the strength and deformation parameters of cohesionless soils, but some valuable data may also be obtained in other soil types.

In view of the high filling height and large amount of soil and rock in the high-filled embankment, the variation law of the displacement field, stress field, and plastic zone of embankment body reinforced by dynamic compaction with different energy levels and the optimal compaction energy were analyzed by means of numerical simulations and field tests. Taking the embankment section of the Ping-Zan highway as an example, the construction scheme of dynamic compaction was designed, and the optimum tamping times and effective dynamic compaction depth of the embankment filled with soil-rock were obtained through the field test. The study showed that the displacement field and the stress field are redistributed after applying single-point compaction, and the volume of the shear plastic zone increases. The optimal number of slams for high-filled granular soil is 7 times, and the effective depth of dynamic compaction is 4.

Все системы должны заработать через пять минут. Грег Хейл убил одного из младших сотрудников лаборатории систем безопасности и взял в заложники моего старшего криптографа. Если нужно, используйте против всех нас слезоточивый газ.

 Но это же абсурд, - не согласилась Сьюзан.  - Ни один из новых шифрованных файлов нельзя вскрыть без ТРАНСТЕКСТА. Вероятно, Цифровая крепость - это стандартный алгоритм для общего пользования, тем не менее эти компании не смогут его вскрыть.

Cone penetration test

Правда, это было не то прикосновение, какое он рисовал в воображении, представляя себе их первый физический контакт, но все же… Хейл долго с изумлением смотрел на нее, затем медленно повернулся и направился к своему терминалу. Одно ему было абсолютно ясно: распрекрасная Сьюзан Флетчер бьется над чем-то очень важным, и можно поклясться, что это никакая не диагностика. ГЛАВА 28 Сеньор Ролдан восседал за своим столом в агентстве сопровождения Белена, чрезвычайно довольный тем, как умело обошел глупую полицейскую ловушку. Немецкий акцент и просьба снять девушку на ночь - это же очевидная подстава. Интересно, что они еще придумают. Телефон на столе громко зазвонил.

Вгляделся в полоску на пальце и пристыжено покраснел.  - О Боже, - хмыкнул он, - значит, эта история подтверждается. Беккеру даже сделалось дурно. - Прошу прощения.


PDF | Dynamic cone penetration test (DCPT) is widely used for field quality Its application to predict the engineering properties of soil is globally measure the strength of surface layers and developed relationships between DCP the strength, as measured with the DCP, and the elastic deformation.


Field Test and Numerical Simulation of Dynamic Compaction of High Embankment Filled with Soil-Rock

Вы позволите поговорить с вами об. Беккер заколебался. - Видите ли, я, честно говоря, очень спешу.  - Он надеялся, что отказ представителю самого мощного разведывательного ведомства не слишком большая глупость с его стороны, но партия в сквош начиналась через сорок пять минут, а он дорожил своей репутацией: Дэвид Беккер никогда не опаздывает на партию в сквош… на лекцию - да, возможно, но на сквош -. - Постараюсь быть краткой, - улыбнулась Сьюзан Флетчер.

 Начинаем отключение резервного питания. Приготовиться. Приступайте. - Мы не успеем! - крикнула Соши.  - На это уйдет полчаса.

3 Comments

  1. Niamh S. 30.05.2021 at 05:14

    Dynamic cone penetration DCP is a field test that is used as a substitute for other penetration tests because it is portable, low cost, quick and simple to use.

  2. Seymour A. 31.05.2021 at 17:39

    PDF | Dynamic cone penetration test (DCPT) is a fast, economical and easy to conduct. It is widely used to assess the strength of natural and compacted. In this research, the behavior of soil with a high content of gypsum (%) out to study the effects on strength and deformation of cyclic soaking and.

  3. Dionisia A. 06.06.2021 at 07:11

    The cone penetration or cone penetrometer test CPT is a method used to determine the geotechnical engineering properties of soils and delineating soil stratigraphy.