Deep static sounding test device and construction method

Abstract

The invention relates to a deep static sounding test device and a construction method. The device comprises a hydraulic clamp holder, a stress application cross beam, a hydraulic jack and the like, the hydraulic clamp holder can carry out various operations on a probe tube and / or a probe rod, and a hydraulic console, an adjuster and the like cooperate to achieve precise control over all the parts. The construction method comprises the steps of device leveling, data line and pipeline connection, casing guide hole opening, probe rod penetration collection, casing on-demand penetration and lifting and the like, and a calculation method for the critical penetration depth of the probe rod is provided. The side friction resistance of the probe rod can be reduced, the rigidity and the lateral constraining force of the probe rod are enhanced, the testing depth and the hole forming quality are effectively improved, deep rock-soil micro-disturbance in-situ investigation is achieved, operation is easy and convenient, the system is stable, and good economic and technical benefits and popularization prospects are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of geotechnical engineering investigation, and specifically to a deep static penetration test device and a construction method, which aims to solve the problems of insufficient depth and limited accuracy of static penetration test in deep geotechnical engineering investigation. Background Art

[0002] With the implementation of the national deep underground space strategy, the accurate acquisition of physical and mechanical parameters of deep rock and soil and the accurate description of stress state have become hot topics in the industry, and geotechnical engineering surveys are facing huge challenges. At present, the conventional method to understand the properties of ultra-deep formations is to drill and coring in combination with indoor geotechnical tests, but such methods will greatly disturb the deep soil, making it difficult to accurately obtain the physical and mechanical parameters and stress state of the deep soil, which in turn affects engineering design and construction.

[0003] The static penetration test is an in-situ testing method for quickly obtaining the physical and mechanical parameters of the in-situ soil. It can be used for soil layer division, soil classification, foundation soil bearing capacity determination, sand liquefaction identification, etc. It has the advantages of convenience, efficiency, and accuracy, but its test depth is often limited and it is difficult to meet the needs of deep geotechnical exploration. When conducting a static penetration test, as the penetration depth of the probe increases, the frictional resistance of the side wall of the probe rod will gradually increase, the flexibility coefficient of the probe rod will increase, and the required penetration power will increase. After reaching a certain depth, the penetration power of the equipment will exceed the critical compressive load of the probe rod, which will cause the probe rod to bend, affecting the quality of the hole, and even causing the probe rod to break in severe cases. How to increase the test depth of the static penetration test is a key issue in the promotion and application of the static penetration test in deep geotechnical engineering exploration.

[0004] Patent document CN202111620182.9 discloses a marine pore pressure static penetration device and method for silty soil formations. A smaller hydraulic jack system and a larger hydraulic jack system can cooperate with each other to drive their corresponding piston rods to lower the probe rod and the pore pressure static penetration probe to achieve continuous penetration of the probe into the silty soil formation; when the inner piston rod reaches the bottom, the outer piston rod of the outer hydraulic jack is switched to descend to drive the probe rod and the pore pressure static penetration probe to penetrate, and the inner piston rod of the inner hydraulic jack is simultaneously raised; after the outer piston rod reaches the bottom, the inner piston rod simultaneously rises to the top, and then drives the probe rod to penetrate again in a cycle, so that the probe rod is always in a downward penetration state, and the pore pressure static penetration probe is continuously penetrated into the formation at a constant rate, but the test depth of the static penetration test cannot be increased.

[0005] Patent document CN201610614294.6 discloses a static penetration device with casing function, including: a main frame, a base is arranged in the lower part of the main frame, penetration cylinders are installed on both sides of the base, the casing is passed through the middle of the base, the probe is inserted into the casing, and the lower end of the probe is connected to the upper end of the static penetration probe. The beneficial effects of the present invention are: the friction of the formation at a certain depth on the probe chain is reduced to almost zero through the action of the casing, and a greater penetration depth can be achieved under the same penetration force; at the same time, the casing provides radial constraints for the probe, minimizes the bending of the probe due to deflection, prevents the probe from breaking, and maximizes the success rate of deep static penetration. However, the device cannot automatically center, clamp, or correct the probe and casing, and the drag reduction effect is limited. Summary of the invention

[0006] The existing construction conditions of static penetration tests are difficult to meet the needs of deep geotechnical engineering investigations. In order to increase the test depth of static penetration tests, the present invention proposes a novel deep static penetration test device and construction method. The device and construction method can reduce the side friction of the probe rod during the penetration process, increase the stiffness and lateral constraint of the probe rod, greatly improve the test depth and hole quality of the static penetration test, realize in-situ investigation of deep rock and soil under micro-disturbance, and greatly improve the accuracy and efficiency of deep geotechnical engineering investigations. Therefore, it has a good prospect for promotion and application.

[0007] To achieve the above-mentioned purpose, the present invention provides a deep static penetration test device, including a hydraulic clamp, a force beam, a hydraulic jack, a hydraulic cylinder, a hydraulic regulator, a hydraulic control console, a casing, and a probe rod;

[0008] The probe rod is sleeved in the casing, and the hydraulic clamp performs centering, clamping, deviation correction and release operations on the casing and / or the probe rod;

[0009] The force-adding crossbeam is connected to the hydraulic jack, and the force-adding crossbeam is clamped and connected to the hydraulic clamper, and the lifting and lowering of the hydraulic jack drives the lifting and lowering of the hydraulic clamper;

[0010] The hydraulic control console controls the probe rod and / or casing by controlling the hydraulic clamp;

[0011] The hydraulic regulator adjusts the oil pressure in the hydraulic cylinder through the hydraulic oil delivered by the hydraulic control console, thereby controlling the lifting and lowering of the hydraulic jack;

[0012] The force-adding crossbeam is connected with the hydraulic clamp, and the lifting and lowering of the hydraulic jack drives the lifting and lowering of the hydraulic clamp.

[0013] Furthermore, the hydraulic clamp includes a hydraulic pipe, a hydraulic adjustment chamber, a connecting pipe, a slip piston, a limiting ring, an arc slip and a hydraulic chamber.

[0014] Furthermore, the hydraulic clamp comprises 3 groups of 6 pairs of hydraulic push slips, which are evenly distributed on the limit ring at an angle of 60°.

[0015] Furthermore, the hydraulic control console is provided with hydraulic pipes, sealing nuts, hydraulic adjustment chambers, penetration operating levers, lifting operating levers, clamping operating levers, and releasing operating levers, which are used to control the centering, clamping, deviation correction, and release of the probe rod and / or casing by the hydraulic clamp.

[0016] Furthermore, the system also includes a limit beam, which is used to increase the lateral rigidity of the hydraulic cylinder and the lateral constraint of the probe rod and / or casing during the penetration process.

[0017] Furthermore, the system also includes a drag reducer, and the drag reducing liquid pipe automatically or uniformly transports the drag reducer into the casing, so that the drag reducer is evenly attached to the outside of the probe rod, reducing the friction between the side wall of the probe rod and the soil layer.

[0018] Furthermore, the system also includes a centering leveler and a leveling base. The centering leveler is placed on the leveling base. Whether the device is level is determined by observing the centering leveler, and the leveling base can adjust the bubble of the centering leveler to the center. The leveling base can be placed on a static probe vehicle or used in conjunction with a ground anchor.

[0019] The present invention also provides a construction method for performing a deep static penetration test using the above device, which is characterized by comprising the following steps:

[0020] S1, level the test device to ensure that the test device is in a horizontal state;

[0021] S2, place the opening casing and the reaming probe on the first one, connect the reaming probe to the probe, and connect the data collector to the probe to ensure that the data collector can normally collect data from the probe;

[0022] S3, connect the hydraulic pipes and drag reduction liquid pipes to each device respectively, and perform a loading test on the hydraulic operating table to ensure the normal operation of the hydraulic clamp and the hydraulic jack;

[0023] S4, using a hydraulic clamp to clamp the opening casing to pre-drill the hole. After the drilling is completed, the first reaming probe rod together with the probe is inserted to the opening depth to reaming the hole;

[0024] S5, after the above steps are completed, the probe rod is clamped by a hydraulic clamp and the probe rod is continuously and uniformly penetrated. During the penetration of the probe rod, a drag reducer is delivered, data is collected at intervals, and the probe rod is automatically corrected by the hydraulic clamp to ensure that the probe rod penetrates vertically. At the same time, the state of the probe rod is checked to see if it is normal. If the state of the probe rod is normal, the penetration continues. If the state of the probe rod is abnormal, the next step is executed;

[0025] S6, when the state of the probe rod is abnormal, the probe rod is lifted to a certain height by the hydraulic clamp, and then the casing is clamped and penetrated to a certain depth;

[0026] S7, repeat the above steps S5 and S6 until the hole depth requirement is met, and then terminate the test;

[0027] S8, after the construction is completed, close the drag reducer, first lift the casing to the workbench, then lift the probe to the workbench, and conduct a probe quality inspection. After the inspection is correct, send the test data, clean the probe, and process the test data.

[0028] Furthermore, in S5, by observing the stress state during the penetration of the probe rod, it is judged whether the shape of the probe rod is normal and whether it is necessary to penetrate the casing to increase the lateral constraint of the probe rod; the penetration rate is 20±5mm / s, and data is collected every 0.1m of penetration.

[0029] Furthermore, the expansion probe is in the shape of an elongated strip as a whole, and has an outward protrusion structure in the middle of the casing; the opening casing body is in the shape of an elongated strip, and the bottom of the casing is a conical structure, which is convenient for penetrating the soil during the penetration process and reduces resistance.

[0030] The present invention has the following beneficial effects:

[0031] (1) The present invention can realize the coordinated operation of multifunctional components: the hydraulic clamp can realize automatic centering, clamping, deviation correction and release operations on the probe rod and casing, can adapt to different sizes, ensure the verticality of the hole, and facilitate the accurate acquisition of deep foundation soil parameters; the hydraulic cylinder assists the rapid penetration and withdrawal of the probe rod and casing; the hydraulic controller can flexibly adjust the penetration speed and power of the device; the drag reducer automatically and uniformly pumps the drag reducer to reduce the friction of the probe rod side wall; the hydraulic operating table accurately controls the movement of the clamp and the hydraulic cylinder, and the various components work closely together to ensure the efficient implementation of the test.

[0032] (2) The unique probe rod and casing combination technology expands the hole diameter by connecting the first expansion probe rod to the probe, reduces the contact area between the probe rod and the soil layer, and thus reduces the friction resistance of the probe rod interface; by adding casing to the outside of the probe rod, the lateral constraint force of the probe rod can be increased, the lateral deformation of the probe rod under axial pressure can be reduced, the verticality of the hole can be ensured, the test accuracy of deep static penetration test can be improved, the risk of probe rod bending deformation can be reduced, and the penetration depth and hole quality of static penetration test can be significantly improved, meeting the stringent requirements of deep geotechnical engineering investigation on accuracy and depth.

[0033] (3) The present invention includes five components: an operating table, a penetration device, a clamp, a drag reducer, and a power system. It proposes a complete deep static penetration test construction method. Through the reasonable coordination of the various components, the deep static penetration test can be carried out efficiently, greatly improving the engineering survey depth of the static penetration test, which is conducive to giving full play to the engineering survey advantages of static penetration in the field of in-situ testing, and has good economic and technical benefits. At the same time, the clear calculation method of the critical penetration depth of the probe rod provides a key theoretical basis for construction, ensuring that the entire construction process is scientific and orderly, the data is reliable, and the survey efficiency and accuracy are greatly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for describing the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0035] Figure 1 It is a cross-sectional view of the deep static penetration test device in the embodiment;

[0036] Figure 2 It is a structural diagram of the hydraulic operating table in the embodiment;

[0037] Figure 3 This is the structural diagram of the hydraulic clamp;

[0038] Figure 4 This is the structural diagram of the expansion probe;

[0039] Figure 5 This is the structural diagram of the lead hole casing;

[0040] Figure 6 The deep static penetration test construction method and construction process in the embodiment;

[0041] In the figure: 1-forced crossbeam; 2-hydraulic jack, 21 anti-shear bolts; 3-hydraulic clamp, 31 hydraulic pipe, 32-hydraulic adjustment chamber, 33-connecting pipe, 34-slip piston, 35-limiting ring, 36-arc slip, 37-hydraulic chamber; 4-sealing ring; 5-hydraulic cylinder; 6-limiting beam; 7-centering leveler; 8-leveling base; 9-hydraulic regulator, 91-hydraulic pipe, 92-sealing nut, 93-hydraulic regulating valve, 94-oil pipeline; 10-drag reducer, 101 drag reducing liquid pipe; 11-probe rod, 111-expansion rib; 12-casing, 121-conical cutting edge; 13-probe; 14-hydraulic control console, 141-hydraulic pipe, 142-sealing nut, 143-hydraulic regulating chamber, 144-lifting operating lever, 145-penetration operating lever, 146-clamping operating lever, 147-releasing operating lever. DETAILED DESCRIPTION

[0042] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0043] It should be understood that when used in this specification and the appended claims, the term "comprising" indicates the presence of described features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or collections.

[0044] In order to simplify the drawings, only the parts related to the present invention are schematically shown in each figure, and they do not represent the actual structure of the product. In addition, in order to simplify the drawings and facilitate understanding, in some figures, only one of the parts with the same structure or function is schematically drawn or marked. In this article, "one" not only means "only one", but also means "more than one".

[0045] It should be further understood that the term “and / or” used in the specification and appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0046] In the embodiments shown in the drawings, the indications of directions (such as up, down, left, right, front and back) used to explain the structure and movement of the various components of the present invention are not absolute but relative. These descriptions are appropriate when these components are in the positions shown in the drawings. If the descriptions of the positions of these components change, the indications of these directions also change accordingly.

[0047] In addition, in the description of the present application, the terms "first", "second", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0048] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the specific implementation methods of the present invention will be described below with reference to the accompanying drawings. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings and other implementation methods can be obtained based on these drawings without creative work.

[0049] As attached Figures 1 to 5 As shown in the figure, the deep static penetration test device consists of a hydraulic clamp, a force beam, a hydraulic jack, a sealing ring, a hydraulic cylinder, a limit beam, a hydraulic regulator, a drag reducer, a centering leveler, a leveling base, and a hydraulic control console. The hydraulic clamp 3 is provided with a hydraulic pipe 31, a hydraulic adjustment chamber 32, a connecting pipe 33, a slip piston 34, a limit ring 35, an arc slip 36 and a hydraulic cavity 37. The hydraulic control console 14 can use the hydraulic pipe 141 to transport hydraulic oil into the hydraulic adjustment chamber 32, and then adjust the hydraulic pressure in the hydraulic cavity 37 through the connecting pipe 33 to push the hydraulic oil into the hydraulic adjustment chamber 32. The movable slip piston 34 pushes three groups of six pairs of arc slips 36 to realize the centering, clamping, deviation correction and release of the probe rod 11 and the casing 12, and assists the penetration and lifting of the probe rod and the casing; the hydraulic regulator 9 is provided with a hydraulic pipe 91, a sealing nut 92, a hydraulic regulating valve 93 and an oil delivery pipe 94, and the hydraulic control console 14 can deliver hydraulic oil to the hydraulic regulator 9 through the hydraulic pipe 91 and the sealing nut 92, and the hydraulic regulating valve 93 and the connecting pipe 94 can be used to adjust the oil pressure in the hydraulic cylinder 5, thereby controlling the lifting and lowering of the hydraulic jack 2; the booster beam 1 and the hydraulic The hydraulic jack 2 is connected by a shear bolt 21, and the lifting and lowering of the hydraulic jack 2 can drive the penetration and lifting of the probe rod 11 and the casing 12 clamped by the hydraulic supporter 3; the limit beam 6 can increase the lateral stiffness of the hydraulic cylinder 5 and the lateral constraint of the probe rod 11 and the casing 12 during the penetration process; the drag reducer 10 can automatically and uniformly pump the drag reducer into the casing through the drag reducing liquid pipe 101, and evenly adhere to the outer side of the probe rod to reduce the friction between the side wall of the probe rod and the soil layer; the adjustment base 8 is provided with a centering and leveling instrument 7, which can be observed by the centering and leveling instrument The leveler 7 determines whether the device is horizontal. The bubble of the centering leveler 7 can be adjusted to the center by adjusting the base 8. The adjusting base 8 can be placed on a static probe vehicle or used in conjunction with a ground anchor. The hydraulic control console 14 has a hydraulic pipe 141, a sealing nut 142, a hydraulic adjustment bin 143, a lifting operating lever 144, a penetration operating lever 145, a clamping operating lever 146, and a releasing operating lever 147. The four operating levers can control the centering, clamping, deviation correction and release of the hydraulic clamp 3 to the probe rod 11 and the casing 12, and can control the penetration and lifting of the hydraulic jack 2.

[0050] As a preferred embodiment, the hydraulic clamp 3 includes 3 groups of 6 pairs of hydraulic jacking slips 36, which are evenly distributed at 60° on the limit ring 35, and can adapt to probe rods 11 and casings 12 of different sizes. At the same time, it has automatic centering and correction functions, which can realize the rapid assembly of the probe rod 11 and casing 12, ensure the verticality of the hole during the penetration process, and facilitate the accurate acquisition of the physical and mechanical parameters of the deep foundation soil.

[0051] As a preferred embodiment, the hydraulic operating platform 14 includes four operating levers, which can control the hydraulic clamp 3 and the hydraulic jack 2 at the same time, which is convenient and efficient.

[0052] As a preferred embodiment, the drag reducer 10 can automatically and evenly pump the drag reducer so that it is evenly attached to the outside of the probe rod 11, thereby reducing the friction resistance at the interface between the side wall of the probe rod 11 and the soil layer.

[0053] As a preferred embodiment, the expansion probe rod 11 is provided with expansion ribs 111, which can increase the support point between the probe rod 11 and the casing 12, reduce the contact area between the probe rod 11 and the soil layer, and reduce the friction of the side wall of the probe rod 11; the pumped drag reducer can penetrate into the cavity between the expansion ribs 111 and the soil layer along with the probe rod 11 at a uniform speed, thereby playing an interface drag reduction role.

[0054] As a preferred embodiment, the lower end of the first borehole casing 12 is provided with a replaceable conical cutting edge 121 , which is beneficial to the penetration of the casing 12 and prevents soil from entering the casing and affecting the penetration of the probe rod 11 .

[0055] When the present invention is used, the probe rod 11 and the casing 12 are respectively inserted into the hydraulic clamp 3 and the limit beam 6, and the operating lever on the hydraulic operating platform 14 is controlled to realize the centering and deviation correction of the hydraulic clamp 3 to the probe rod and the casing, and the rise and fall of the hydraulic jack 2 are realized, so as to realize the penetration of the probe rod and the casing; the penetration rate and penetration power of the hydraulic jack 2 can be controlled by controlling the hydraulic regulating valve 93 on the hydraulic regulator 9; during the penetration process of the probe rod, the frictional resistance between the probe rod and the soil layer can be reduced by pumping the drag reducing liquid through the drag reducer 10; by penetrating a certain length of casing, the lateral restraint force of the probe rod can be increased, thereby increasing the critical penetration depth of the probe rod, and realizing the static penetration engineering survey of ultra-deep formations.

[0056] The deep static penetration test device in the embodiment is suitable for in-situ testing engineering surveys of ultra-deep formations, with the purpose of improving the depth and accuracy of deep foundation soil surveys. The hydraulic clamp can be used to match probes and casings of different diameters, and the spacing can be automatically aligned and actively corrected, thereby improving the efficiency of engineering surveys. The probe and casing penetration technology can greatly reduce the friction resistance between the probe and the soil layer interface, increase the lateral restraint force of the probe, and improve the penetration depth and hole quality of the static penetration test.

[0057] like Figure 5As shown in the figure, the deep static penetration test construction method and construction process in this embodiment are as follows: (3) Figure 1 For the system shown, the construction method and construction process are as follows:

[0058] ① Preparation: Level the test device according to the terrain characteristics of the hole position to ensure that the construction hole coincides with the hole position; pass the test data line through the probe rod and casing in turn (based on test experience, the casing length can be 40% to 60% of the depth of the exploration hole), ensure that the expansion probe rod and the opening casing are placed first, and connect the expansion probe rod to the probe, and connect the probe to the data collector. Perform a signal acquisition test before the test to ensure that the probe collects data normally; connect the hydraulic pipe and the drag reduction liquid pipe to each device respectively, and perform a hydraulic operating table loading test to ensure the normal operation of the hydraulic clamp and the hydraulic jack; use the hydraulic clamp to clamp the opening casing, use the hydraulic jack to penetrate the casing, and conduct a test pre-drilling (depending on the fill thickness, the drilling can be 1 to 3 meters); after the drilling is completed, penetrate the first expansion probe rod together with the probe to the drilling depth.

[0059] ② Vertical penetration of the probe rod and data collection: After the preliminary preparation work is completed, the penetration test of the probe rod and the probe head is carried out. The hydraulic clamp is used to clamp the probe rod, and the probe rod is penetrated continuously and uniformly at a penetration rate of 20±5mm / s. Data is collected while penetrating, and data is collected once every 0.1m. The hydraulic clamp will automatically center and correct the probe rod through 3 sets of evenly distributed hydraulic jacking slips to ensure vertical penetration of the probe rod. During the penetration of the probe rod, the drag reducer is used to uniformly pump drag reducing fluid into the guide bore casing to reduce the friction between the side wall of the probe rod and the soil layer.

[0060] ③Casing penetration: By observing the stress state of the probe rod during penetration, determine whether it is necessary to penetrate the casing to increase the lateral constraint of the probe rod; before penetrating the casing, lift the probe rod for 1m to prevent the probe rod from continuing to penetrate under force during the casing penetration process; when penetrating the casing, use a hydraulic clamp to clamp the casing, and then penetrate it at a uniform speed. The casing penetration depth should penetrate the soft soil layer so that the restraining effect of the casing can be maximized.

[0061] ④ Secondary penetration: Repeat steps ② and ③ in sequence until the hole depth survey requirements are met, and then terminate the test; when conducting the penetration test, always pay attention to the status of the probe rod to ensure the quality of the hole and avoid excessive deformation of the probe rod that may cause the hole to tilt or the probe rod to break.

[0062] ⑤ Lifting of probe rod and casing: When the construction is completed, close the drag reducer, lift the casing to the workbench first, and then lift the probe rod to the workbench, and conduct probe quality inspection. If there is no problem, send the test data to the technician, process and calculate the data, and clean the probe in time.

[0063] The construction method in this embodiment mainly uses the probe rod and casing in combination. As the penetration depth of the static penetration test gradually increases, the critical pressure resistance of the probe rod will gradually decrease, and the lateral deformation will gradually increase, seriously affecting the quality of the hole formed in the test. In order to increase the penetration depth of the static penetration test, it is necessary to increase the critical pressure of the probe rod. By adding a certain length of probe tube to the outside of the probe rod, the lateral constraint of the probe rod can be increased, the flexibility coefficient of the probe rod can be reduced, and the critical penetration depth of the probe rod can be increased. The drag reducing fluid pumped by the drag reducer is evenly attached to the outside of the probe rod, and a smooth film can be formed between the interface of the probe rod and the soil layer, reducing the lateral friction between the probe rod and the soil layer, thereby reducing the penetration force required to penetrate the probe rod and reducing the axial force on the probe rod.

[0064] In order to provide a key theoretical basis for construction, ensure that the entire construction process is scientific and orderly, the data is reliable, and effectively improve the efficiency and accuracy of the survey, this embodiment also provides a critical penetration depth calculation method for the probe rod, and the calculation process is as follows:

[0065] The penetration process of the probe rod is similar to the stability problem of the compression rod. With the increase of the penetration depth and the bearing capacity of the soil layer, the end resistance, side resistance and side friction resistance of the probe rod gradually increase, and the required penetration power also gradually increases, that is, the axial pressure on the probe rod increases. In order to ensure the quality of the hole, the axial pressure F c Less than the critical load F when the probe is compressed cr

[0066] F c ≤F cr =π 2 EI / (μ·l) 2 (1)

[0067] As the penetration depth increases, the axial pressure force of the probe rod can be expressed as F c

[0068] F c =A·q c +πdl·f s (2)

[0069] And the relationship between the two is

[0070] π 2 EI=μ 2 AHr c l 2 +πdμ 2 f s l 3 (3)

[0071] From the above formula, the critical penetration depth l of the probe can be obtained: cr

[0072] When the probe size is constant, in order to increase the critical penetration depth l cr , by reducing the length factor μ and the lateral friction f s accomplish.

[0073] When a certain length of casing is added to the outside of the probe rod, the stress state of the probe rod changes from "one end fixed, the other end movable but not rotatable" to "one end fixed, the other end hinged", and the length factor μ is reduced from 1 to 0.7.

[0074] After adding the casing, the friction force F on the side wall of the probe is s

[0075] F s =πd(ll t )·f s (4)

[0076] After adding the drag reducer, the friction force F' on the side wall of the probe s

[0077] F s '=πd(ll t )·αf s (5)

[0078] Where: F c —Axial pressure on the probe (kN); F cr —The critical axial load that the probe can withstand (kN); E—Elastic modulus of the probe (MPa); I—Moment of inertia of the probe (m 4 ); μ—length factor of the probe rod; l—penetration depth of the probe rod (m); A—effective area of ​​the cone tip of the probe (m 2 );q c —The cone tip resistance of the probe (MPa); d—The outer diameter of the probe rod (mm); f s —Equivalent side friction of the probe side wall (kPa); cr — critical penetration depth of the probe (m); F s —Equivalent friction force on the side wall of the probe rod after adding a certain length of casing (kN); t —Casing penetration depth (m); F' s —The equivalent friction force (kN) on the side wall of the probe rod after adding a certain length of casing and under the action of the drag reducer; α—the side friction correction factor of the drag reducer.

[0079] The embodiments described above are part of the embodiments of the present invention, rather than all of the embodiments. The detailed description of the embodiments of the present invention is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

Claims

1. A deep static penetration test device, characterized in that: Including hydraulic clamp, force beam, hydraulic jack, hydraulic cylinder, hydraulic regulator, hydraulic control console, casing, probe rod; The probe rod is sleeved in the casing, and the hydraulic clamp performs centering, clamping, deviation correction and release operations on the casing and / or the probe rod; The force-adding crossbeam is connected to the hydraulic jack, and the force-adding crossbeam is clamped and connected to the hydraulic clamper, and the lifting and lowering of the hydraulic jack drives the lifting and lowering of the hydraulic clamper; The hydraulic control console controls the probe rod and / or casing by controlling the hydraulic clamp; The hydraulic regulator adjusts the oil pressure in the hydraulic cylinder through the hydraulic oil delivered by the hydraulic control console, thereby controlling the lifting and lowering of the hydraulic jack; The force-adding crossbeam is connected with the hydraulic clamp, and the lifting and lowering of the hydraulic jack drives the lifting and lowering of the hydraulic clamp.

2. The deep static penetration test device according to claim 1, characterized in that: The hydraulic clamp comprises a hydraulic pipe, a hydraulic regulating chamber, a connecting pipe, a slip piston, a limiting ring, an arc slip and a hydraulic chamber.

3. The deep static penetration test device according to claim 2 is characterized in that: The hydraulic clamp comprises 3 groups of 6 pairs of hydraulic push slips, which are evenly distributed on the limit ring at 60 degrees.

4. The deep static penetration test device according to claim 1 is characterized in that: The hydraulic control console is provided with hydraulic pipes, sealing nuts, hydraulic adjustment chambers, penetration operating levers, lifting operating levers, clamping operating levers, and releasing operating levers, and is used to control the centering, clamping, deviation correction, and release of the probe rod and / or casing by the hydraulic clamp.

5. The deep static penetration test device according to claim 1 is characterized in that: The system also includes a limit beam, which is used to increase the lateral rigidity of the hydraulic cylinder and the lateral constraint of the probe rod and / or casing during the penetration process.

6. The deep static penetration test device according to claim 1, characterized in that: The system also includes a drag reducer. The drag reducing liquid pipe automatically or uniformly transports the drag reducer into the casing, so that the drag reducer is evenly attached to the outside of the probe rod, reducing the friction between the side wall of the probe rod and the soil layer.

7. The deep static penetration test device according to claim 1 is characterized in that: The system also includes a centering leveler and a leveling base. The centering leveler is placed on the leveling base. The leveling of the device can be determined by observing the centering leveler. The leveling base can adjust the bubble of the centering leveler to the center. The leveling base can be placed on a static probe vehicle or used in conjunction with a ground anchor.

8. A construction method for conducting a deep static penetration test using the device according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1, level the test device to ensure that the test device is in a horizontal state; S2, place the opening casing and the reaming probe on the first one, connect the reaming probe to the probe, and connect the data collector to the probe to ensure that the data collector can normally collect data from the probe; S3, connect the hydraulic pipes and drag reduction liquid pipes to each device respectively, and perform a loading test on the hydraulic operating table to ensure the normal operation of the hydraulic clamp and the hydraulic jack; S4, using a hydraulic clamp to clamp the opening casing to pre-drill the hole. After the drilling is completed, the first reaming probe rod together with the probe is inserted to the opening depth to reaming the hole; S5, after the above steps are completed, the probe rod is clamped by a hydraulic clamp and the probe rod is continuously and uniformly penetrated. During the penetration of the probe rod, a drag reducer is delivered, data is collected at intervals, and the probe rod is automatically corrected by the hydraulic clamp to ensure that the probe rod penetrates vertically. At the same time, the state of the probe rod is checked to see if it is normal. If the state of the probe rod is normal, the penetration continues. If the state of the probe rod is abnormal, the next step is executed; S6, when the state of the probe rod is abnormal, the probe rod is lifted to a certain height by the hydraulic clamp, and then the casing is clamped and penetrated to a certain depth; S7, repeat the above steps S5 and S6 until the hole depth requirement is met, and then terminate the test; S8, after the construction is completed, close the drag reducer, first lift the casing to the workbench, then lift the probe to the workbench, and conduct a probe quality inspection. After the inspection is correct, send the test data, clean the probe, and process the test data.

9. The construction method according to claim 8, characterized in that: In S5, the stress state during the penetration of the probe rod is observed to determine whether the shape of the probe rod is normal and whether it is necessary to penetrate the casing to increase the lateral constraint of the probe rod; the penetration rate is 20±5mm / s, and data is collected every 0.1m of penetration.

10. The construction method according to claim 8, characterized in that: The expansion probe is in the shape of an elongated strip as a whole, and has an outward bulge in the middle of the casing; the opening casing body is in the shape of an elongated strip, and the bottom of the casing is a conical structure, which is convenient for penetrating the soil during the penetration process and reduces resistance.

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