WO2016070252A1

WO2016070252A1 - Sampling device for soft and very soft soils with cable-actuated jaws and soil flow between the jaws and the sampling tube

Info

Publication number: WO2016070252A1
Application number: PCT/BR2015/000164
Authority: WO
Inventors: Fernando Artur BRASIL DANZIGER; Ian SCHUMANN MARQUES MARTINS; Graziella Maria FAQUIM JANNUZZI; Gilberto FERREIRA ALEXANDRE; Silvio PINHEIRO DA SILVA JUNIOR
Original assignee: Universidad Federal Do Rio De Janeiro
Priority date: 2014-11-03
Filing date: 2015-11-03
Publication date: 2016-05-12
Also published as: BR202014027481U2; BR202014027481Y1

Abstract

As described in the description and depicted in the drawings, the present utility model application relates to a structural arrangement for devices for collecting superficial and deep samples of soft and very soft soils. More specifically, a sampling device is provided with a cutting-holding mechanism having the shape of a perfectly spherical cap with jaw-like blades connected thereto, designed to cut the sample at the end of the thrust-in process, in such a way that the sample is not pushed into the sampling device and is prevented from slipping, ensuring that the sample can be retrieved and minimising squashing effects both while the sampling device is thrust in and while the sample is retrieved.

Description

"THE OSTRACTOR FOR SOFT AND VERY MOLD SOILS WITH CABLE DRIVEN JAW DEVICE AND WITH SOIL FLOW BETWEEN JAW AND PIPE

SAMPLE "

SUBJECT This utility utility patent application refers to a constructive arrangement for surface and deep sample collectors of soft and very soft soils. More specifically, a sampler equipped with a mechanism known as a perfect spherical cap-shaped cutter-support with blades connected as jaws, which aims at the end of the crimping to cut the sample so as not to push it into inside the sampler, as well as preventing it from slipping, thus ensuring its recovery, minimizing the dimming effects, and greater efficiency and yield in the sampling procedure. With this sampler, there is no need for post-crimping time to extract the sample, as in other samplers, according to ABNT NBR 9820: 1997. In addition there is a guarantee of sample recovery, even of very low resistance, since the support is provided by the sampler base. A key feature of the cutter-support mechanism is that it has a section designed in a very small horizontal plane in the open condition to offer the lowest possible crimping resistance. The idea was for soil outside the pipe to "flow" during crimping between the pipe's outer wall and the cutter-support mechanism. If this were not the case, the crimping of the sampler would create a dent in the soil to be sampled below the sampler during the sampling process. APPLICATION FIELD

The object of the present utility model patent application belongs to the field of application in geotechnics. The subject falls under the theme of foundations, with soil studies of in situ foundations, which are carried out before construction work, based on soil sampling (ICPC E02D 1/04). The issue is also relevant to the field of research or analysis ¹ of the materials by determining their chemical or physical properties, uti-! using specific sampling equipment, with solid state samples and specific extraction tool (ICPC G01 N1 / 08). The subject j It can also fit into other themes, such as ports - which are usually built in regions with extremely soft soils - and works in need of sedimentation studies. Finally, any area of knowledge - including environmental - where soft or very soft soil sampling is required may benefit from the sampler.

TECHNICAL STATE

With the advancement of research in the study stress-strain-resistance of soil properties, it is becoming increasingly evident the importance of investigating soil structure, to define its mechanical behavior, both regarding its resistance and its deformability. . For this, it is of fundamental importance to collect undisturbed samples. According to Hvorslev (1949), samples are classified as:

. unrepresentative samples - consist of mixtures of soil or rock layer materials, or are samples where some mineral constituents may have been removed, for example by washing during the water circulation process in percussion drilling. The earthy materials suspended in this circulating water are examples of unrepresentative samples. Such samples do not represent the subsoil materials, but serve only for preliminary classification and depth determination where there are variations in the soil profile. They also serve to help you program the definition of representative and undisturbed sample depths;

2. representative samples - contain all the constituent minerals of the layers from which they were taken and have not been contaminated by materials from other layers, but the soil structure has been seriously disturbed (dented) and the moisture content may have been modified. They are for soil identification and classification, but not for testing where mechanical properties should be obtained. Examples can be cited as shell or helical auger samples and samples obtained with the standard SPT sampler;

3. undisturbed samples - samples in which the material was subjected to such a small perturbation which are suitable for all laboratory tests and determinations of strength properties and permeability deformabili _¬ ity, among others. Remember that there is always a disturbance associated with the variation in the state of stress suffered by the during field sampling and after withdrawal. Examples are block samples and those obtained with stationary piston thin-walled (Shelby) samplers, Denison, Sherbrooke and Lavai, all of which are well established by international practice.

Although the sampler described here is capable of obtaining undisturbed samples of very good soft and very soft soils - used for the determination of stress-strain-resistance properties of the material in laboratory tests - it can also be used in cases where, Although there is no need for undisturbed but only representative samples, they are difficult to sample because of the low material consistency.

The sampling process and the denting

According to Martins (201 1), denting is the partial or total destruction of the soil structure, understood as structure the original arrangement or spatial arrangement that the set of grains forming that soil presents in the field. In the case of saturated soft clays, denting is an undrained process and as such without volume variation. Thus, the denting is the destruction of the soil structure by the distortions imposed on it throughout the entire sampling and specimen preparation process, as listed below, according to Ladd and DeGroot (2003):

1 . extension distortion due to the relief of the total vertical tension through the sampling hole opening;

2. distortion of the sampled soil elements near the sampler inner wall during its crimping;

3. soil expansion after crimping and before tube extraction into the soil; 4. tube extraction;

5. transport and storage of samples;

6. extruding the sample from inside the tube;

7. specimen preparation.

The usual Brazilian practice, recommended by ABNT NBR 9820: 1997, is the use of internal clearance, whose main purpose is to reduce the shear stresses between the sample and the internal wall of the sampler during the crimping process. In this condition, immediately after nailing, and especially without By using a piston, there would not be sufficient shear strength in the walls to support the weight of the sample. The sample then expands laterally until it meets the sampler wall, during which some drainage occurs. This is the main reason why a waiting time is required (Martins, 201 1) before extracting the sampling tube with the collected soil sample. Even in the case of samplers without internal backlash there is a need for a holding time, which occurs even in the case of stationary piston samplers.

Ladd and DeGroot (2003) mention that during the extraction of the tube with the sample, the clay under the base of the tube resists removal of the sample tube due to its own resistance and the suction created in the vacuum left by the tube with the sample. sample. In addition, pore pressure in the clay decreases as the pipe is brought to the surface, which may lead to the formation of gas bubbles due to dissolved gas dissolution (e.g. Hight and Leroueil, 2003).

The denting results in changes in various geotechnical parameters of the collected sample, which is discussed in many articles, for example Lunne et al. (1997) and Leroueil and Hight (2003). The most striking effects of denting on the sample with respect to densification trials reported by Ladd (1973), Martins (1983), Martins and Lacerda (1994) are:

1 . Whatever the actual vertical stress, the void index is always lower for the lower quality sample;

2. The greater curvature portion of the graph between the void index by the effective vertical tension becomes less pronounced, making it difficult to determine the overdensity stress;

3. reduction of the estimated value of the overvoltage voltage;

4. increased compressibility in the recompression stretch, causing an increase in the recompression index;

5. decreased compressibility in the virgin compression stretch, causing a decrease in the compression index.

In the case of other laboratory tests, denting also generates changes in the mechanical properties of soils. For example, in the case of anisotropically densified triaxial compression type (CAU) tests for field stresses, higher quality samples provide higher shear strength values and lower deformations to achieve maximum shear stresses (Lunne et al. al., 1997). 15 000164

5 Thus, the limitations associated with the sample recovery process after crimping are (Martins, 201 1):

1 . Due to the internal clearance, after crimping a time should be allowed for the sample to expand and adhere to the wall of the sampler tube. This time is often high, and even waiting 24 hours, the sample is often not recovered;

2. The sample drops when the tube is pulled, which is very common - it should be noted that there are two occasions when this may occur (i) the first, right at the beginning of the sample withdrawal, when the Shelby head does not work. properly, (ti) the second, when the sample is taken from the hole, and the specific weight changes from submerged to natural;

3. When detaching the sample from the massif, it is necessary to apply a rotation to the tube, which causes the bottom - which could be the noblest of the sample (nozzle) - to undergo strong distortions, where this part ends up being discarded for strength and deformability tests.

IDENTIFIED PRIORITIES

There are many types of samplers to collect undisturbed soft clay samples, both on land and at sea, and Hvorslev's (1949) work is a basic reference on this subject. The models are distinguished presented to minimize any disturbance in the soil sample, and seeks FROG ^¬ ram address the limitations associated with the sample recovery process after crimping, in order to make effective and efficient sampling procedure.

In the first sampler model, represented in CN203025002, one observes the form commonly known as the piston sampler. The only figure in this document illustrates the cutting edge soil sampler across the pipe edge (11). In this model, there is no mechanism capable of cutting or even isolating the soil sample at the base of the pipe from the rest of the subsoil being sampled (below the sampler base). In fact, sample recovery depends solely on the friction between the sample and the inner walls of the sampler tube (in addition to the vacuum generated in the piston), as there is no device capable of supporting the sample from its base. In some cases, a bump is applied to the start-up tube 10 to attempt to better secure the sample to the tube at the time of sampling. This model has many disadvantages in that especially the effects of sample dimming during the extraction phase.

Analyzing US5492021, we observe the implementation of an arrangement at the sampler edge, which was developed for the extraction of high strength soil samples. It is thus observed that such an arrangement could be adapted for use in soft soil sampling, but it should be concluded that such a procedure would result in loss of part of the sample due to the collapsing of the fins (11), which would inevitably deform the sample. soil contained between its walls. Another noteworthy fact is the maintenance of the contact of the sample with the subsoil being sampled by the windows (1 18), a fact that similarly has the same disadvantages as the model represented in CN203025002, but in a less pronounced scale. .

By analyzing the documents US4667754 and US4946000, there is a sampler dispo ^¬ purchase of soils, in which there is a sample retaining element (34). It is a hemispherical structure with flexible fins, which are kept in the open position by the introduction of a transverse tube (18). After the crimping of the sample, the bypass tube is removed, causing the flexible fins to return to the hemispherical position, causing the separation between the soil sample and the studied subsoil. Accordingly, it is understood that the model has the same limitations as the model of US5492021, in addition to providing further disturbance to the sample at the time the bypass tube (18) is withdrawn due to its slip relative to the soil mass. Sample. In addition, greater soil rigidity would prevent the fins from closing, so that the operator would not be aware during the sampling operation, causing the system presented to regress to the model presented by document CN203025002.

In the analysis of document CN202770660, a soil sampler arrangement is thus observed which has numerous blades (3) positioned around the end of the sampling tube (1). Such a device resembles the Sherbrooke sampler cutting mechanism (Lefebvre and Poulin, 1979), which is considered the best land use sampler (eg, Hight et al. 1992). However for very soft soils it may not work properly as it has no lateral containment. Thus, the sample can break through its own weight when it can be sampled. This model has as limitations a higher energy expenditure during its grounding, due to the larger contact surface of its edge (1), which directly impacts the disturbance of the sample structure. In addition to this model, a complex drive transmission system to operate the rotation of the blades (3), as shown in the drawing, the blades (3) in the closed position do not close. completely the basis of the sampled soil mass, which causes a change in the stress state of the sample in addition to the stress relief existing in the case of "perfect sampling" (see Ladd and DeGroot, 2003).

Analyzing the model of the documents CN202401459 and CN202648989, the illustrated display has a sound sample segregation mechanism composed by the union of circular sectors (6), until completing a base disk. In this case, the mechanism closes the sectors (6), separating and at the same time pushing up the soil sample confined to the sampler. This displacement generates an additional disturbance in the sample body CN202401459 since during this operation the relative displacement of the sample occurs between the sampler walls (5). In this case, there is also a complex mechanism of cutting operation, and, as in CN202770660, presents potential for mescanism failure due to the various moving parts involved, added to another sample disturbance during the closing of the circular sectors. .

Analyzing the model of document CN202886135, there is a similarity between the cut-support mechanism of that sampler (Figs. 1, 2 and 3) with that of the sampler presented here. This resemblance is only apparent. In fact, this similarity refers only to sample cutting and holding operations. However, the CN202886135 sampler does not allow it to "flow" during the crimping of the sampler into the soil between the cutter-support device and the pipe, which causes the softening of the soil to be sampled, ie the sample. collected by that sampler can in no way be considered a sample of the undisturbed type.

Analyzing the model of document FR2523613A1, we find that it is a sampler capable of retrieving samples of only superficial soft soils, as detailed in that document. In fact, although the cutter-support mechanism appears to bear some resemblance to that of the model presented in this document, in reality the mechanism of document FR2523613A1 can only be operated from the ground surface when cutting, and in no other way. depth. The model presented here performs sampling at any depth from pre-holes, and during crimping of the sampler, in each sampling process, soil "flows" between the pipe wall and the support cutter. 15 000164

8th

INVENTIVE CONCEPT

Considering the research and development efforts in soft soil samplers, it was found that it would be desirable for a new sampler to be developed that had a specimen-cutting device at its base such as the Sherbrooke sampler and that, furthermore, support the sample. In fact, experience with using the Sherbrooke sampler on a very soft clay (Oliveira, 2002} made clear the need for lateral specimen containment. A cutter-support mechanism was designed to cut the sample without pushing it. and support it at the time of extraction to prevent slippage.The base-cutter should provide minimal disturbance to the sample as well as support the entire underside of the sample. different from the Sherbrooke sampler.The cutter-support device is designed to be a spherical cap outside the sampling tube designed to cause soft soil to flow between the sampling tube and the device during the sampling process. the crimping of the sampler, which is essential to avoid denting during the crimping process. The combination of the tube with the cut-off device would allow integral support, either at the base or on the side surface of the specimen. This lower support would have the following advantages:

1 . would avoid the need for internal slack;

2. It would avoid the need to wait for the pore pressure generated in the soil's shear by the pipe to dissipate, with the consequent gain of resistance, which is necessary for the recovery of the sample, both in the case of existence and nonexistence. internal clearance;

3. avoid the imposition of suction on the sample base, which occurs in thin wall samplers (Shelby type) and even piston samplers;

4. Since there is no need for internal friction of the tube for the sample to be recovered, some type of internal lubricant of the tube walls may be employed in order to decrease shear stress at the lateral end of the sample and redistribution. pore pressures following the crimping of the sampler;

5. It would avoid distortion (denting) as it would not be necessary to rotate the tube to separate the sample from the mass. 2015/000164

Moreover, it would also be desirable for the new sampler, like the piston sampler, to guarantee the expulsion of the bushing generated in the pre-drilling process, which is not the case with the thin wall sampler (Shelby type). Once the objectives of the research were delineated, a soft and very soft soil sampler with cable-driven jaw device was developed, with soil flow between the jaws and the sampler tube, which has three main parts:

1 . lower and main part of the sampler, which has the sample cutting mechanism, capable of supporting the weight of the sample. The cutter-support mechanism has been designed to have a section projected on a very small horizontal plane in the open condition (Fig. 17), so as to offer the lowest possible resistance during crimping of the sampler, to avoid dents from the soil to be sampled. The cutter-support mechanism describes a spherical cap. It is driven by surface-operated steel cables. The bevel cutting angle can range from 5 to 20 °;

2. Sampling tube, fixed to the bottom by simple fitting and to ensure constant internal section throughout the sampler. In other words, the new sampler has no internal clearance, or cams, for the reasons discussed earlier. Due to market availability, brass tubes with an internal diameter of 102.5 mm and a thickness of 3 mm were used. The pipe length is 700 mm, however, the sampler concept allows the use not only of pipes of different dimensions but of different materials (PVC, for example). 3. sampler head, which serves to secure the tube to the sampling rod and existing holes for the passage of water and suspended material during the descent of the sampler and during crimping.

It should also be noted that the bottom is removable and reassembled with each sampling, while the sampling tube is replaced with each sample.

Here are some interesting features of the new sampler:

1 . the cutter-support mechanism has been designed to have the smallest section designed to provide the lowest possible crimping resistance (Fig. 17). The idea was that the soil outside the pipe would flow during the crimping between the outer wall of the pipe and the cutting mechanism, thus minimizing the denting of the sample during the crimping process of the sampler; 15 000164

2. the cutter-support mechanism closes completely, allowing even samples to be obtained from extremely soft soils.

ADVANTAGES OF THE MODEL

The present proposal for a new soft and very soft soil sampler with cable-operated jaw device and with soil flow between the jaws and the sampler tube has the advantages over the state of the art of the object in question:

1. When compared to samplers with a sampler tube, it allows the inner wall of the tube to be greased with some lubricating material (eg silicone) to reduce friction, as in an ideal sampling process There would be friction between the ground and the pipe wall. This process, of course, is not possible in a thin-walled tube (even with a piston), since friction is required for sample recovery;

2. With the new sampler the recovery of the sample is assured. In addition, there is greater productivity with the new sampler, as there is no need for any waiting time for the sample to be recovered, unlike thin wall (Shelby type) and even piston samplers;

3. cutting with the support cutter is much less detrimental to the sample than torsional shear in the case of the thin wall sampler and the piston sampler. In addition, the portion of the sample to be used for laboratory testing is far above the cut-off region;

4. even if the tube head were efficient, that is, if it were always capable of generating vacuum at the top of the sample, this does not prevent vacuum from being generated at the bottom of the sample at the time of extraction, in the case of the sampler. Thin wall. The same is true for piston samplers. In the case of the new sampler, the base support prevents this large variation of total stress on the sample;

5. When compared to the Sherbrooke sampler, it provides full lateral restriction by both the lateral surface and the base, allowing very soft samples to be taken, which does not occur with that sampler.

6. when compared to samplers that are able to retrieve depth samples and have cut-support mechanisms, T BR2015 / 000164

11

1 has the advantage of allowing undisturbed samples to be obtained as existing samples cause great disturbance during the crimping process.

7. When compared to a sampler that has a supportive 5-shear mechanism and small disturbance, it has the advantage of not only obtaining surface samples but also depth.

ILLUSTRATIONS

In order to facilitate research and provide understanding of the present patent, as recommended in the report, according to a basic and preferential form of realization prepared by the applicant, reference is made to the accompanying illustrations, which integrate and subsidize the present descriptive report. , a:

Figure 1 - Presents the new sampler (100), in exploded view, presenting all its constituent elements, necessary for its operation, able to highlight the technical-functional improvements presented in the previous section.

Figure 2 - Shows the top view of the sampler containment disk (110).

Figure 3 - Shows the top view of the sampler head (120).

Figure 4 - Shows the side sectional view A-A of the sampler head (120).

Figure 5 - Shows the top view of the guide ring (130).

0 Figure 6 - Shows the side sectional view B-B of the guide ring (30).

Figure 7 - Shows the top view of the connection sleeve (150).

Figure 8 - Shows the D-D side sectional view of the connection sleeve (150).

Figure 9 - Shows the top view of the sampler tip (160).

Figure 10 - Shows the E-E side cross-sectional view of the sampler tip (160 ).5 Figure 1 1 - Shows the front view and the F-F side cross-sectional view of the pivot plate (170) of the cutting jaws (200).

Figure 12 - Shows the front and side views of the sampler holding rod (180).

Figure 13 - Shows the front and side views of the drive rod (190) of the cutting jaws (200). 15 000164

Figure 14 - Shows the front view of the opening control rod (220) of the cutting jaws (200).

Figure 15 - Shows the front, side and top views of the cutting jaw (200).

Figure 6 - Shows the top view of the sampler with open cutting jaws.

Figure 17 - Shows the bottom view of the sampler with the cut jaws open.

Figure 18 - Shows the side view of the sampler during the sampler descent process, penetrating the ground, with the jaws open and the soil flowing between the tube and the jaws.

Figure 19 - Shows the lateral view of the sampler after the interruption of soil penetration in the process of closing the jaws.

Figure 20 - Shows the side view of the sampler, with the jaws closed, before the beginning of the sampler rise with the sample inside.

Figure 21 - Shows the side view of the sampler during the climb, with the sample inside.

DESCRIPTION

As can be seen from the figures presented, the object of the present invention comprises a tube (140) which in their upper part are posi ^¬ tioned, in order, the ring tabs (130), the head (120) and containment disc (110). At its base, the tube 140 receives, in order, the connecting sleeve 150 followed by the sampler tip 160. All elements listed are connected to each other and stabilized via the containment rods (180). The cutting mechanism is represented by the jaws (200) pivoting on the pivot plate (170) which are diametrically coupled to the tip (60) of the sampler. The clamping of the jaws (200) to cut the soil sample is carried out by the drive rods (190) and such actuation can be reversed through the opening command rods (220). The retaining disc (110) is comprised of a thick steel plate which contains at its outer edge the fixing guides (11) and the holes (11) in its body. The mounting guides (1 1 1) receive the dowels (181), where they are fixed with nuts and lockwashers. The holes (112) receive hexagon socket head cap screws securing them to holes (123), joining the containment disc (110) to the sampler head (120).

The sampler head (120) is comprised of a thick steel plate disc (125), solidified at its center by the tube (124), threaded inside, and the tube (122), whose outside diameter (126) equals to the inner diameter (133) of the guide ring (130). The disc (125) has the fixing holes (123) and the holes (121) for drainage and air outlet during the entire sampling process.

The guide ring (130), composed of a tube, has around it the fixing guides (131), which receive the dowels (181) and the steel cables (194) and the draw rods (191) of the drive rods. (90), the steel cables and tie rods of the release cams (220). The existing shoulder (132) receives the end of the tube (140) so as to couple the tube (140) and guide ring (130) without internal shoulders to allow the insertion of the tube (122) without any play.

The pipe-shaped connection sleeve (150) has an inner diameter (152) in the dimensions of the outer diameter of the tube (140). The shoulder (151) accommodates next to the shoulder (163) of the sampler tip (160).

The tube-shaped end (160) of the sampler has the shoulder (161) which accommodates the end (140) of the tube so as not to allow play or bumps in their union. Tip 160 has beveled end 164 which constitutes its crimping blade. The diametrically opposed hinging plates (170) are positioned around, welded or bolted to the tip body (160). Also bolted, welded or riveted, the anchors (182) of the tie rods (180) around the tip (160).

The hinging plates (170), composed of a thin steel plate, have holes (173) in order to position the screws, soldering points or rivets for their attachment to the tip (160). At the top of the plate (170) is a solid prism (171) that contains the closing movement of the cutting jaws (200). In the center of the plate (170) is the pivot (172), where the cutting jaws (200) are fixed to it, which can be fixed by means of lock washers, or even rivets.

The cutting jaws (200) pivot under the pivot (172). Have the arms (201), which contain the hole (202) that receives the pivot (172) and the other hole (203) that receives the pin (195), to fix the jaw (200) to the drive rod (180) . The jaw (200) is formed by a spherical steel cap (204) which It has at its end a bevelled blade (205), and in the upper area of the cap (204), an eye (241) for the attachment of the opening control rod (220) by means of the attachment of the loop (223).

The retaining rods (180) are composed of the billets (181), which have their threadable ends. They are connected to the anchors (182) by means of wire ropes. The drive rods (190) consist of a wire rope (194) which runs through a dowel (191) and attaches to knot (192). This node (192) connects two more wire ropes, which then solidify to the coupling (193), which consists of a kneecap by means of the pin (195). The opening control rods 220 are composed of a wire rope 221, a dowel 222 and a loop 223 at its end.

The use of the new sampler begins with the jaws (200) in the open position, as shown in Figure 18. After the sampler crimping event in the soil to be sampled, the drive rods (190) are triggered through of the cables (194) which, when pulled upwards, pivot the handles (200) by the pivots (172), occluding the jaws (200), cutting the soil sample contained within the tip (160) of the sampler. Thus, when the sampler is extracted from the ground, the sample rises together, supported by the jaws (200) that are closed during the procedure. Due to this mechanism, there is no longer a need for any waiting time for the sample to be detached and extracted.

CONCLUSION

Thus, the soft and very soft soil sampler with cable-driven jaw device and with soil flow between the jaws and the sampler tube is subsidized by unprecedented technical and functional characteristics, presenting an inventive act, based on all research. undertaken throughout its development and is therefore worthy of the legal protection claimed. Although it has been described and illustrated, it is noteworthy that design changes are possible and achievable without departing from the scope of this utility model.

BIBLIOGRAPHIC REFERENCES

HIGHT, DW, BOESE, R., BUTCHER, AR, CLAYTON, CRI SMITH, PR, 1992, Disturbance of Bothkennar clay prior to Laboratory Testing. Géotechnique, v. 42, no 2, pp. 199-217.

HIGHT, D.W., LEROUEIL, S., 2003, Characterization of soils for engineering purposes. Characterization and Engineering Properties of Natural Soils - Tan et al. (eds.), Swets & Zeitlinger, Lisse, v.1, pp. 255-360.

HVORSLEV, M.J., 1949, Subsurface exploration and sampling of civil engineering purposes. The Waterways Experiment Station, Corps of Engineers, U.S. Army, Vicksburg, Miss, 521 p.

LADD, C.C., 1973, Estimating settlements of structures supported on cohesive soils, revision of a paper originally prepared for M.I.T., 1971, Special Summer Program, "Soft Ground Construction", Cambridge.

LADD, C, DEGROOT, D., 2003, Recommended practice for soft ground characterization: Arthur Casagrande Lecture. In: Proceedings of the 12th Panamerican Conference on Soil Mechanics and Geotechnical Engineering, Boston, v. 1, pp. 3-57.

LEFEBVRE, G., POULIN, C, 1979, A new method of sampling in sensitive clay. Canadian Geotechnical Journal, v. 16, no. 1, pp. 226-233.

LEROUEIL, S., HIGHT, D.W., 2003, Behavior and properties of natural soils and soft rocks. Characterization and Engineering Properties of Natural Soils - Tan et al. (eds.), Swets & Zeitlinger, Lisse, v.1, pp. 29-254.

LUNNE, T, BERRE, T, STRANDVIK, S. ₍ 1997, Sample Disturbance Effects in Soft Low Plastic Norwegian Clay. Recent Developments in Soil and Pavement Mechanics, M. Almeida (Ed.), Balkema, pp. 81-102.

MARTINS, I.S.M., 1983, About a new relationship void-stress ratio in soils. M.Sc. Dissertation, COPPE / UFRJ, Rio de Janeiro, RJ, Brazil.

MARTINS I.S.M., 201 1, Foundation Engineering Extension Course lesson notes, PROMINP, UFRJ.

MARTINS, I.S.M. and LACERDA, W.A., 1994, About the ratio of voids index to effective vertical stress in one-dimensional compression. Soils and Rocks, v. 17, no. 3, pp. 157-166, Sao Paulo.

OLIVEIRA, J. T. R. (2002) The influence of sample quality on the stress-strain-resistance behavior of soft clays. Thesis D.Sc., COPPE / UFRJ, Rio de Janeiro.

Claims

CLAIM

Soft and very soft soil sampler with cable-operated jaw device and with soil flow between the jaws and the sampler tube consists of tube (140) and a cutting mechanism characterized by;

- two cutting jaws (200) with two arms (201), two pivoting holes (202) and two holes (203) that connect to the drive rod (180), formed by a spherical steel hub (204) which has at its end a bevelled blade (205) and an eye (241);

- a retaining disc (110) composed of a thick steel plate provided at its outer edge with four fixing guides (11) and four holes (112) in its body;

- a sampler head (120), consisting of a thick steel plate disc (125) with four fixing holes (123) and four drainage holes (121), joined at its center by the threaded tube (124) inside, and the tube (122), whose ^external diameter (126) is equivalent to the inner diameter (133) of the guide ring (130);

- a guide ring (130), composed of a tube, having around it eight fixing and shoulder gutters (131);

- a tube-shaped sampler tip (160) with cam (161), beveled end (164), two diametrically opposed pivot plates (170) welded or bolted to the tip body (160) and four anchors ( 182) bolted, welded, or riveted around the tip (160);

- two pivot plates (170), composed of a thin nine-hole steel plate (13), with the solid prism (171) at the top and pivot (172) roseible at its center;

- four retaining rods (180) composed of billet (181) with rose-end, anchor (182) connected by steel cable

- two drive rods (190) each composed of wire rope (194) which runs inside a pin (191), and attaches to the node (192), integral with two couplings (193) containing a pin ( 195).

- two opening control rods (220) each composed of a wire rope (221), a dowel (222) and a loop (223) at its end.