Sealed consolidation apparatus with controllable temperature and drainage distance

Abstract

The invention discloses a sealed consolidometer with controllable temperature and drainage distance, which comprises a temperature control and data acquisition unit, a consolidation unit for applying load to a soil sample and consolidating the soil sample, and a constant-temperature water tank unit for controlling the temperature of the soil sample, the temperature control and data acquisition unit is connected with other units through data acquisition lines, and the consolidation unit is connected with the constant-temperature water tank through screws; the invention further provides a using method of the temperature-controllable sealed consolidation apparatus, and the consolidation apparatus is included. The temperature of the consolidated soil body can be controlled, the sealing performance of the device is ensured by adopting a combined sealing ring, the bottom of the constant-temperature water tank is provided with a pore water pressure monitoring interface, the top of the consolidation unit is provided with an interface capable of controlling the drainage distance of the soil body, various variable control and monitoring of the soil body consolidation experiment are realized, and the experimental data are closer to the reality.

Description

Technical Field

[0001] The invention relates to the technical field of geotechnical engineering indoor testing, and in particular to a sealed consolidation instrument with controllable temperature and drainage distance. Background Art

[0002] Consolidation test is one of the important contents of geotechnical indoor experimental technology. Consolidation test is an experimental work to test the engineering properties of soil and obtain the physical and mechanical indicators of soil. Consolidation test (also known as compression test) is the most basic method to study soil compression. The consolidation test is to prepare the original soil in its natural state or the artificially prepared disturbed soil into soil samples of a certain specification, and then place it in a consolidation instrument to compress and deform under different loads and under complete lateral confinement conditions. Soil is a product of nature. Its formation process, material composition and engineering properties are extremely complex, and become more complex with its stress state, stress history, loading rate and drainage conditions. Therefore, in order to enable the consolidation experiment to control different experimental conditions and ensure the accuracy of the experimental results, it is necessary to use suitable and reliable consolidation instruments to conduct consolidation experiments.

[0003] Calculating foundation settlement is a key and challenging issue in geotechnical engineering. Based on the different causes of foundation settlement, total settlement can be divided into three components: instantaneous settlement, primary consolidation settlement, and secondary consolidation settlement. Instantaneous settlement occurs the instantaneously upon load application, with deformation occurring completely during the construction period. Primary and secondary consolidation settlements, on the other hand, are closely time-dependent and persist for years or even decades after construction is complete. Existing literature and field data demonstrate that primary consolidation deformation and creep deformation interact, jointly influencing foundation settlement and long-term settlement.

[0004] Commonly used methods for calculating foundation settlement in engineering assume that creep deformation occurs only after primary consolidation. After primary consolidation is complete, foundation settlement is the sum of primary consolidation settlement and secondary consolidation settlement. However, in deep soft soil foundations in actual engineering, due to their strong viscosity and low permeability, soil units near the drainage boundary have a shorter primary consolidation time, leading to earlier creep deformation. Furthermore, the consolidation time for the entire soft soil foundation is very long. Therefore, the creep effect during the primary consolidation stage cannot be ignored, and the interaction mechanism between consolidation and creep deformation needs to be considered.

[0005] At present, the experimental equipment used for conventional consolidation is relatively complete. In contrast, the experimental equipment used to study long-term soil consolidation is relatively backward. For long-term consolidation experiments, the experimental cycle is relatively long, and the sealing of the instrument and the temperature of the soil sample have an important impact on the accuracy of the experiment. The accuracy of the model parameters is a key factor in correctly calculating the settlement of deep foundations. The traditional acquisition of deformation parameters is based on one-dimensional confined consolidation tests of 2cm or 4cm high soil samples in the laboratory, which is inconsistent with the actual deformation of deep soft soil foundations of more than ten meters or even dozens of meters on site. Some scholars have studied the influence of deformation parameters on drainage distance by directly raising the ring knife. However, directly raising the ring knife will inevitably increase the frictional resistance between the soil sample and the inner wall of the ring knife. The soil is no longer in an unconfined compression state, and shear deformation occurs. Moreover, the height of the ring knife is limited by the test conditions, and the height to which the ring knife can be raised is limited. Therefore, the distance of the drainage surface has an important influence on the consolidation of the soil. However, the existing technology lacks a consolidation instrument that can freely control the drainage distance. In addition, the influence of temperature on long-term consolidation experiments is mainly reflected in the consolidation rate and consolidation quality. It will also affect the effective stress of the soil, thereby affecting the deformation and strength of the soil.

[0006] In summary, based on the mechanism of the existing confined consolidation test, developing an oedometer that can control different drainage distances and consolidation temperatures and has good sealing performance to restore the interaction between consolidation deformation and creep deformation of deep soft soil foundations on site and improve the theoretical level of engineering design on deep soft foundations are currently difficult and key issues to be solved in this field. Summary of the Invention

[0007] The purpose of the present invention is to overcome the shortcomings and deficiencies of the prior art and provide a sealed consolidation instrument with controllable temperature and drainage distance. The problems raised in the above-mentioned background technology are solved by setting a consolidation unit for applying load to the soil sample and consolidating the soil sample, a constant temperature water tank unit for controlling the consolidation temperature, and a drainage hole for controlling the drainage distance.

[0008] To achieve the above object, the present invention provides the following technical solutions:

[0009] A sealed consolidation instrument with controllable drainage distance and temperature, comprising a temperature control and data acquisition unit, a consolidation unit for applying a load to a soil sample and consolidating the soil sample, and a constant temperature water tank unit for controlling the temperature of the soil sample. The temperature control and data acquisition unit is connected to the other units via a data acquisition line, and the consolidation unit is connected to the constant temperature water tank via screws.

[0010] The temperature control and data acquisition unit includes a pore pressure sensor for collecting consolidation unit data, a displacement sensor and a data acquisition system for collecting consolidation unit data, and a temperature control system for collecting the real-time temperature of the constant temperature water tank;

[0011] The consolidation unit includes a soil sample, a gland, a guide assembly, fixing screws, a combined sealing ring, an O-ring, a consolidation instrument base and a consolidation filter layer;

[0012] The constant temperature water tank unit includes a heat preservation top cover, a temperature sensor, an electric heating element, and a water flow component;

[0013] Preferably, the oedometer base and the constant temperature water tank are concave bases, and the guide assembly is fixed to the oedometer base with fixing bolts. The internal space of the guide assembly is used to apply load to the soil sample and consolidate the soil sample. The soil sample is filtered through two groups of consolidation filter layers in sequence, the first group is arranged at the bottom of the gland, and the second group is arranged at the bottom of the guide assembly. The discharged water is finally discharged from the drainage hole of the gland.

[0014] Preferably, the consolidation unit is provided with an O-ring groove for placing an O-ring, and a water collection groove for collecting water discharged by soil consolidation;

[0015] Preferably, the combined sealing ring of the consolidation unit is provided on both sides of the gland, and comprises an O-shaped rubber inner ring and an outer ring filled with polytetrafluoroethylene. When the gland moves downward, the inner ring is compressed to provide elasticity, so that the outer ring is in close contact with the guide assembly, thereby reducing the friction resistance between the combined sealing ring and the guide assembly.

[0016] The fixing screw fixes the guide assembly to the base of the consolidation instrument and squeezes the O-ring to form a sealing boundary seal at the bottom of the consolidation unit;

[0017] Preferably, the cavity between the base of the oedometer and the guide assembly is filled with water to prevent evaporation of water inside the consolidated soil;

[0018] Preferably, the gland is provided with an inclined hole, the inlet end of the inclined hole is at the top of the gland and does not pass through the pressure head, and the outlet end of the inclined hole is at the center position of the bottom of the gland, which ensures that the pressure point is at the center position and the seepage outlet point is also at the center point position;

[0019] Preferably, the constant temperature water tank is provided with a water flow component to ensure that the water temperature is balanced throughout the water tank. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0021] Figure 2 This is a schematic diagram of the thermal insulation top cover structure of the present invention;

[0022] Figure 3 This is a schematic diagram of the guide assembly and gland structure of the present invention;

[0023] Figure 4 This is a structural diagram of a constant temperature water tank according to the present invention;

[0024] Figure 5 This is a schematic cross-sectional view of the overall assembly of the present invention;

[0025] In the figure: 1. Insulation top cover; 2. Pressure cover; 3. Guide assembly; 4. Constant temperature water tank; 5. Temperature control and data acquisition system; 6. Temperature sensor; 7. Upper fixing screw hole; 8. Loading groove; 9. Electric heating element; 10. Water flow assembly; 11. Drive motor; 12. O-ring groove; 13. Lower fixing screw hole; 14. Water collection groove; 15. Pore pressure sensor interface; 16. Seepage hole; 17. Upper consolidation filter layer; 18. Soil sample; 19. Lower consolidation filter layer; 20. Fixing screw; 21. Combined sealing ring groove. DETAILED DESCRIPTION

[0026] The present invention will be described in further detail below with reference to the embodiments and drawings, but the embodiments of the present invention are not limited thereto.

[0027] See also Figure 1-5 , the present invention provides a technical solution:

[0028] A sealed consolidation instrument with controllable drainage distance and temperature, comprising a temperature control and data acquisition unit, a consolidation unit for applying a load to a soil sample and consolidating the soil sample, and a constant temperature water tank unit for controlling the temperature of the soil sample. The temperature control and data acquisition unit is connected to the other units via a data acquisition line, and the consolidation unit is connected to the constant temperature water tank via fixing screws.

[0029] The temperature control and data acquisition unit includes a temperature sensor 6 for collecting the real-time temperature of the constant temperature water tank, an electric heating element 9 for maintaining a constant temperature in the constant temperature water tank, and a pore pressure sensing interface 15 for collecting consolidation unit data;

[0030] The consolidation unit includes a gland 2, a guide assembly 3, an upper consolidation filter layer 17, a soil sample 18, a lower consolidation filter layer 19, and fixing screws 20;

[0031] The constant temperature water tank unit includes a heat preservation top cover 1, an electric heating element 9, a water flow component 10, and a driving motor 11;

[0032] The temperature control and data acquisition system 5 is connected to the temperature sensor 6, the electric heating element 9, and the drive motor 11 through the data acquisition line, which can control the temperature in the water tank and the speed of the water flow component; it is connected to the pore pressure sensor 15 through the conduit to collect the pore water pressure under different consolidation pressures.

[0033] The consolidation unit is provided with an O-ring groove 12 for placing an O-ring, and a water collection groove 14 for collecting water discharged by soil consolidation; the water collection groove 14 is in a mesh shape;

[0034] The combined sealing ring grooves 21 of the consolidation unit are provided on both sides of the gland 2, and include an O-shaped rubber inner ring and an outer ring filled with polytetrafluoroethylene. When the gland 2 moves downward, the inner ring is compressed to provide elasticity, so that the outer ring and the guide assembly 3 are in close contact, reducing the friction resistance between the combined sealing ring and the guide assembly 3, thereby ensuring the sealing of the device while better controlling the experimental accuracy.

[0035] The gland 2 is provided with a seepage inclined hole 16. The inlet end of the inclined hole is located at the top of the gland 2 and does not pass through the pressure head. The outlet end of the inclined hole is located at the center position of the bottom of the gland 2. This ensures that the pressure point is at the center position and the seepage outlet point is also at the center point position. In this way, the pressure is uniform, the drainage rate is increased, and the water squeezed out of the soil sample is easily discharged. The seepage inclined hole is connected to pipes of different lengths to achieve a change in the consolidation drainage distance.

[0036] The fixing bolts 20 fix the guide assembly 3 to the constant temperature water tank 4 and squeeze the O-ring placed in the O-ring groove 12 to form a sealing boundary seal at the bottom of the consolidation unit;

[0037] The constant temperature water tank 4 is a concave semi-open base with a certain thickness at the bottom. The fixing bolts 20 fix the guide assembly 3 to the constant temperature water tank 4. The internal space of the guide assembly 3 is used to apply load to the soil sample and consolidate the soil sample. The soil sample is filtered through two sets of consolidation filter layers 17 and 19 in sequence. The first set is located at the bottom of the gland 2, and the second set is located at the bottom of the guide assembly 3. The two sets of consolidation filter layers 17 and 19 are filled with filter stones.

[0038] The water flow component 10 drives the water in the constant temperature water tank by driving the motor 11 to ensure that the temperature in the water tank is uniform;

[0039] The above is a preferred embodiment of the present invention, but the embodiment of the present invention is not limited to the above content. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A sealing consolidation instrument with controllable drainage distance and temperature, comprising a temperature control and data acquisition unit, characterized in that: It also includes a consolidation unit for applying a load to the soil sample and consolidating the soil sample, and a constant temperature water tank unit for controlling the temperature of the soil sample. The temperature control and data acquisition unit is connected to the other units via a data acquisition line, and the consolidation unit is connected to the constant temperature water tank via screws. The temperature control and data acquisition unit includes a pore pressure sensor for collecting consolidation unit data, a displacement sensor and a data acquisition system for collecting consolidation unit data, and a temperature control system for collecting the real-time temperature of the constant temperature water tank; The consolidation unit includes a soil sample, a gland, a guide assembly, fixing screws, a combined sealing ring, an O-ring, a consolidation instrument base and a consolidation filter layer; The constant temperature water tank unit includes a heat preservation top cover, a temperature sensor, an electric heating element, and a water flow component.

2. The oedometer according to claim 1, characterized in that The base of the oedometer and the constant temperature water tank are concave bases, and the fixing bolts fix the guide assembly to the base of the oedometer. The internal space of the guide assembly is used to apply load to the soil sample and consolidate the soil sample. The soil sample is filtered through two groups of consolidation filter layers in succession. The first group is located at the bottom of the pressure cover, and the second group is located at the bottom of the guide assembly. The discharged water is finally discharged from the drainage hole of the pressure cover.

3. The oedometer according to claim 1, characterized in that The consolidation unit is provided with an O-ring groove for placing an O-ring, and a water collection groove for collecting water discharged by soil consolidation.

4. The oedometer according to claim 1, characterized in that The combined sealing ring of the consolidation unit is arranged on both sides of the pressure cover, including an O-shaped rubber inner ring and an outer ring filled with polytetrafluoroethylene. When the pressure cover moves downward, the inner ring is compressed to provide elasticity, so that the outer ring is tightly attached to the guide assembly, reducing the friction resistance between the combined sealing ring and the guide assembly.

5. The oedometer according to claim 1, characterized in that: The cavity between the base of the oedometer and the guide assembly is filled with water to prevent the evaporation of water inside the consolidated soil.

6. The oedometer according to claim 1, characterized in that The gland is provided with an inclined hole, the inlet end of the inclined hole is at the top of the gland and does not pass through the pressure head, and the outlet end of the inclined hole is at the center position of the bottom of the gland, which ensures that the pressure point is at the center position and the seepage outlet point is also at the center point position.

7. The oedometer according to claim 1, characterized in that The constant temperature water tank is provided with a water flow component to ensure that the water temperature in each part of the water tank is balanced.

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