SU1086066A1 - Method of pressiometric testing of soil in well and pressiometer for performing same - Google Patents

Abstract

1. The method of pressiometric testing of soil in a well, including loading the walls of the well with incremental pressure steps to stabilize the soil deformations at each step, measuring them and determining the deformative characteristics of the soil according to the data obtained, in order to increase the pressiometric test performance, load production t a given volume of air compressed in a tank of a known volume to the initial pressure at a given stage, and after stabilization of the soil deformation, comfort changes the air pressure and determines the radius of the probe by the formula g Vyo (p; -. Pc) 4t crVj - the volume of the probe at all steps preceding the calculated one, h - length (height of the probe shell. 2. Method according to 1, characterized in that the compression of the air for loading the soil in two successive stages is carried out simultaneously in two tanks of a known identical volume. 3. A soil pressure tester in a well, including a probe with a housing and an elastic sheath, a high pressure source, a main line and measuring adapted and featuring and SP and in that it is provided with two capacitances form

Description

capacity through distributor-be. 1086066 alternately under them

The invention relates to a geology engineer, in particular to the study of the physicomechanical properties of soils during engineering and geological surveys in dp construction. The known method of pressure testing of the soil in the well, including loading the walls of the wells with incremental pressure stages, withstanding each stage is compressed until the deformation is conditionally stabilized by measuring the radial displacements of the probe chamber shell and determining the soil characteristics. In a method, a probe pre-meter is used, which includes a working chamber with a tastic sheath, a high pressure source and measuring devices for measuring pressure and radial movements of the C 1 shell. The disadvantage of these test methods and devices is a considerable duration of one test. em a few hours, and sometimes more than a day. The closest technical solution to the present invention is a pressure tester for testing a soil in a well, including a probe with a housing and an elastic sheath, a high pressure source, a main line and measuring devices and a method for pressing soil testing in a well using this pressure meter, including wall loading. wells

fp-p v- (P-p) Vt (p p).

 n n P n / 0 n-1 0 - 1

Fo

Rp

radius of the probe body,

cm: P. atmospheric pressure, kgf / cm;

ITMP; PO)

- overpressure in the tank of a known volume at the pth loading stage. You can use the steps of increasing pressure to stabilize the deformations of the soil at each step, measure them and determine the deformative characteristics of the soil G2D from the data obtained. The disadvantage of this method and device is the testing capacity due to the fact that the method involves maintaining a constant pressure until the deformation is stabilized, consisting in the repeated supply of compressed air from a high pressure source to the probe. This pressure adjustment leads to the occurrence of ground oscillations and, as a result, to a significant degree of soil stabilization process. The purpose of the invention is to increase the performance of the pressiometric tests. The goal is achieved by the fact that according to the method of pressometric testing of soil in a well, including loading the walls of the well with incremental pressure steps to stabilize the soil deformation at each step, measuring them and determining the soil’s deformation characteristics according to the obtained data compressed in a vessel of known volume to the initial pressure at a given stage, and after stabilization of the soil deformation, the changed air pressure is recorded and Are the radius of the probe according to the formula P | - overpressure after soil deformation at the p-th loading stage, kgf / cm overpressure after stabilization of the soil deformation (p-1) -th loading stage, kgf / cm, internal volume of the air cavity of a known volume, cm, VP - internal volume whether the gauge-1 to the probe, cm, is the increment of the probe volume at all steps preceding the calculated one, cm, b is the length (height) of the probe shell. Moreover, the compression of the air for loading the soil with two subsequent pressures is produced simultaneously in two containers of a known identical volume. A pressurier for soil testing in a well, including a probe with a body and an elastic sheath, high pressure sources and measuring devices, is equipped with two containers of known identical volume with devices for controlling the air volume and pressure control, while dinene with a high pressure source, atmosphere and main from the house zones with the possibility of their alternate connection. FIG. 1 is a diagram of a pressometer for testing a soil in a well; FIG. 2 - Pressiometer, general view; in fig. 3 - pressometric curve. The pressiometer consists of a probe 1 with an elastic sheath, line 2, which is connected to one of two tanks 5 and 6, of known and identical volume, through regulating valves 3 and 4, and through the valve 7 to the atmosphere. The containers 5 and 6 are connected through a control valve 8-10 and a reduction valve 11 to a high-pressure source 12, for example, cylinders with compressed gas, as well as to pressure gauges 13 and 14, respectively, through the valves 15 and 16 to the atmosphere. Each of the containers 5 and 6 is made with the possibility of adjusting the air volume, for example, by means of addition or drainage / not shown a known volume of liquid. The method of pressiometric soil testing in the well is carried out using ice-screen imaging. Before starting work, the volume of the air cavities of the tanks 5 and 6 is determined by a certain amount of known relation to the volume of line 2, which is preliminarily measured by pouring and draining it. Before the probe 1 is lowered into the borehole of the tank 5 and 6, the line 2 is connected to the atmosphere through valves 15, 16 and 7, and the elastic shell of the probe 1 is pressed against the body, i.e. camera zone 1 has zero volume. The probe 1 is fed by line 2 into the well, after which the soil is loaded with a predetermined volume of air compressed to the initial for this stage Pn (i.e., P, P P ;, -, P.,) in containers 5 J,. .., Pj) in containers 5 and 6 of known volume. At each of the stages, the predetermined volume of air is bypassed from tanks 5 and 6 of a known volume to trunk 2 with probe 1 in such a way that as far as (ground leveling the pressure in the system, the capacity of the known volume of main probe decreases to the final value P (i.e. P, P P P) f 2, ..., 1., ..., i p; The loading of the soil is effected by increasing pressure steps; this in one tank 5 is created by an overpressure P, and in tank 6 by an over pressure P + -, with Gates 8 and 9 closed at P | P; s. Then the pressure PJ from tank 5 through valve 3 is passed into the mag ral 2 with probe 1. At the end of the process de (; the law at this stage of loading, using valve 3, turn off line 2 and probe t from tank 5 and valve 4 connect tank 6 with overpressure P - + -, i.e. bypass in line 2 and probe 1. During the process of deforming the soil at this stage, an overpressure is created at the next loading stage. At the end of the research, valve 7 releases pressure in probe 1, the elastic shell returns to its original position, and the device is ready for testing Runt on the new depth. At each step of loading, the value of the initial P and the pressure established after stabilization of the deformation P are fixed and the total increment of the probe volume is calculated by calculation. that pos1 (p-pMv 2 In p / R o Using the data obtained, calculate the deformative characteristics of the soil, for example, the modulus of soil deformation E according to the formula LJ - K. D- I where r is the initial radius of the well, cm; ДР - pressure increment on walls

between two points on the linear portion of the deformation increment AB (Fig. 3), moreover

, | , kgf / cm,

damage to the movement of a SteATS ki well, corresponding to dr, see

k is the corrective multiplier. An example of a specific implementation of the method pressiometric testing of soil in the well.

The tests are carried out with a probe with a diameter of 108 mm in a borehole with a diameter of P2 mm at a depth of 6.25 m at a groundwater level of 2.7 m, at 7 and after a bypass, and a stabilized condition and holding time P is recorded. The pressure Pj, and P is fixed by pressure gauges 13 and 14c, with a division value of 0.064 kgf / cm, which ensures the necessary accuracy of radius increment measurement, i.e. 0.1 mm. In the process of experience on the software

microcalculus tore (input Rr and G ,,

in divisions) at each of the steps

P

determined by cAV cAv n

.14

(both the inner shell and the outer shell, taking into account the thinning of the rubber), it is necessary to control its volume when held (test "The final radius of the probe R at the nth loading stage is found according to IVWP 4P1 pi / o-1 o / j . P) lomite soil. In containers of known volume 5 and 6 (Figs. 1 and 2, a volume of cm is set equal to the internal volume Vp of line 2 to probe 1. At each of the loading stages in the containers of known earthworks, sequentially and alternately (for each of the 2 stages: used containers) pressure is established

The modulus of soil deformation is calculated from the values of the linear portion of the pressometric curve (steps 4–8; respectively, 34.1; 34.2; 34.2; 34.2)

 ° 5: 850-j765 - / In the prototype, similar measurements take about 4 hours instead of 40 min according to the proposed method. Yu

The use of the present invention allows to significantly increase the performance of the pressiometric tests by reducing the time of carrying out the test several times, as well as reducing the complexity of the operations of monitoring cHHMaefUx parameters.

FIG.

5, g

2 IG S W Pp kgo / sn 2

8 Fig.Z

Claims (3)

I. Method of pressometric testing of soil in a well, including loading the walls of the well with incremental pressure steps to stabilize the soil deformations at each step, measuring them and determining the deformable characteristics of the soil according to the obtained data, in order to pick up the pressiometric test performance, the loading is performed the volume of air compressed in a tank of known volume to the initial pressure at a given stage, and after stabilization of the soil deformation, register and the changed air pressure and determine the probe radius by the formula —- {g (1-1 ΣΞ ) V (Pn? ^R.) 4g WITH 59 where R _about - the radius of the probe body, cm; Russia - atmospheric pressure, kgf / cm ² ; R _p - excess pressure in a tank of known volume on ₍ η-th stage of loading; Р ^ - overpressure after soil deformation at the nth ₍ loading steps, kgf / cm ² ; Р „„ - overpressure after stabilization of soil deformation at the (p-1) -th loading stage, kgf / cm ² ; V p - the internal volume of the air cavity capacity of a known volume, cm ^; - internal volume of the master program; - the increment of the volume of the probe at all levels prior to the calculated, cm ³ ; B is the length (height) of the probe shell. 2, Method according to π. I, which differs from I in that the compression of air for loading the soil in two subsequent steps is carried out simultaneously in two tanks of a known identical volume. 3. Presiometer for soil testing in the well, including a probe with a housing and an elastic sheath, a high pressure source, mages. strap and measuring devices, distinguishing frost by the fact that it is supplied with two capacities of the known 1 = 1 5 and 1086066 whether "Probe, cm \ 1086066 an identical volume with devices for regulating the air volume and controlling the pressure; in this case, the capacities are connected by means of distribution devices to a high pressure source, the atmosphere, and a main line with a probe with possible alternate connection of them. one