CN114880747A - Cement mixing pile soil layer identification method based on mixing energy consumption - Google Patents
Cement mixing pile soil layer identification method based on mixing energy consumption Download PDFInfo
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Abstract
The invention provides a cement mixing pile soil layer identification method based on mixing energy consumption, which comprises the following steps: determining a plurality of first soil layer types contained in a construction area through reconnaissance, and acquiring physical and mechanical parameters of each first soil layer type; dividing the design construction depth into a plurality of depth sections; obtaining loss power consumption corresponding to each depth section; in the construction process, acquiring power head information at intervals of preset acquisition time, and calculating a first actual value of work done by a power head according to a first preset calculation rule when a stirring head descends to the bottom end of each target depth section; calculating a calculation value of work done by the power head when the soil layer type of the target depth section is assumed to be the first soil layer type according to a second preset calculation rule; and determining the soil layer type of the target depth section based on the first actual value and each calculated value. According to the invention, the soil layer types corresponding to different depths are identified through different work done by the power head on the stirring head through different soil layer types and the actual work done by the power head.
Description
Technical Field
The invention belongs to the technical field of mixing pile construction, and particularly relates to a cement mixing pile soil layer identification method based on mixing energy consumption.
Background
Different technological parameters need to be adopted for different soil layers during construction of the deep cement mixing pile, only 1 investigation borehole is usually adopted in one construction area in engineering practice, and all mixing pile constructions adjust the construction technological parameters according to the soil layer distribution conditions of the investigation borehole. However, a large number of engineering soil layers are complicated in distribution, and the actual construction soil layer distribution is not consistent with the exploration holes, so that the construction process parameters are not suitable for the soil layers, so that the construction quality of partial pile sections is poor, and even the piles are not formed.
At present, a mixing pile machine commonly used in the market comprises a pile embracing device, a plurality of drill rods arranged on the pile embracing device, a power head driving the drill rods to rotate and a plurality of mixing heads respectively arranged at the bottom ends of the drill bits, wherein the bottom ends of the mixing heads are provided with cutting blades, and the outer side wall of the mixing heads is provided with a plurality of layers of blades.
Disclosure of Invention
The invention aims to provide a cement mixing pile soil layer identification method based on mixing energy consumption.
The invention is realized by the following technical scheme:
a cement mixing pile soil layer identification method based on mixing energy consumption comprises the following steps:
surveying a construction area, determining a plurality of first soil layer types contained in the construction area, and acquiring physical and mechanical parameters of each first soil layer type;
obtaining a design construction depth, and dividing the design construction depth into a plurality of depth sections;
before construction, acquiring the loss power consumption of the mixing pile machine when the mixing head descends to the bottom end of each depth section, and acquiring the loss power consumption corresponding to each depth section;
in the construction process, acquiring power head information every preset acquisition time, and recording the depth section where the stirring head is located as a target depth section when the stirring head descends to the bottom end of each depth section, wherein the power head information comprises a voltage value and a current value of the power head;
based on the acquired power head information, calculating a first actual value of work of the power head on the stirring head in a period of time when the stirring head passes through a target depth section according to a first preset calculation rule;
based on physical and mechanical parameters of multiple first soil layer types and the loss power consumption corresponding to the target depth section, calculating a calculated value of work of the power head on the stirring head passing through the target depth section in a period of time when the soil layer type of the target depth section is assumed to be various first soil layer types according to a second preset calculation rule, and obtaining a calculated value corresponding to each first soil layer type;
and determining the soil layer type of the target depth section based on the first actual value and the calculated value corresponding to each first soil layer type.
Further, the step of calculating a first actual value of the work performed by the power head on the stirring head during the period of time when the stirring head passes through the target depth section according to a first preset calculation rule comprises:
calculating a first actual value of the work performed by the power head on the agitator head over the period of time through the target depth interval according to the following formula:
in the formula, W Fruit of Chinese wolfberry A first actual value of work done by the power head to the stirring head in a period of time passing through a target depth section, U is a voltage value of the power head, n' is the number of pieces of power head information acquired in a period of time passing through the target depth section, and I i And the current value in the ith power head information acquired by the stirring head in the time period of passing through the target depth segment is i-1, 2, … …, n ", and t is the preset acquisition time.
Further, the physical and mechanical parameters comprise cohesion, friction angle, weight, friction coefficient and lateral pressure coefficient;
and when the soil layer types of the target depth section are assumed to be various first soil layer types according to a second preset calculation rule, the step of calculating the work done by the power head to the stirring head in the period of passing through the target depth section comprises the following steps:
sequentially selecting a target soil layer type from a plurality of first soil layer types, and calculating the calculated value of the work of the stirring head in a period of time when the soil layer type of the target depth section is assumed to be the target soil layer type according to the following formula:
W meter ＝W Consumption unit +(M 1 +M 2 )nt′2π (2)
In the formula, W Meter When the soil layer type for the target depth section is assumed to be the first soil layer type,the calculated value of the work done by the power head over the period of time the stirring head passes the target depth, W Consumption unit Loss power, t, for the target depth segment ′ Time for the stirrer head to pass through the target depth zone, M 1 The friction torque of soil and the drill rod, d is the diameter of the drill rod, n' is the number of layers of the overburden layer above the target depth section, and sigma zi Vertical effective stress, k, of soil body in the i-th overlying soil layer si Is the lateral pressure coefficient of the soil of the overburden layer on the ith layer, mu si The friction coefficient h between the soil of the soil layer covering the ith layer and the drill rod i Thickness of the topsoil layer of the i-th layer, c u C is the cohesion of the first soil layer type assumed for the target depth segment,
a friction angle of the first soil layer type assumed for the target depth segment, σ is overburden pressure above the target depth segment, M 2 For the torque between the stirring head and the soil,/ 1 Length of cutting blade, B 1 Width of cutting blade, theta 1 Angle of inclination of cutting blade, V Through tube For the head descent speed, n for the head rotation speed, S t For soil sensitivity, k is the number of leaf layers, l 2 Is the length of the blade, B 2 Is the width of the blade, theta 2 Is the pitch angle of the blade.
Further, the derivation process of equation (5) is as follows:
according to the principle of a cross plate shear test, the method comprises the following steps:
in formula (II) to' 1 For overcoming the moment, M ', required for the shear strength of the cylindrical soil mass' 2 The moment required for overcoming the shear strength of the top surface soil body and the bottom surface soil body, M is the total moment for overcoming the shear strength of the soil body, d is the diameter of the drill rod, l is the length of the blade or the length of the cutting blade, B is the width of the blade or the width of the cutting blade, and theta is the blade inclination angle or the cutting blade inclination angle;
in the construction process, the relation that the cutting blade stirs and destroys the soil body is as follows:
h 1 ＝B 1 sinθ 1 -h 2 (10)
in the formula, h 2 Thickness of undisturbed soil for cutting blade stirring, h 1 Thickness of disturbed soil for cutting blade agitation;
substituting equation (9) and equation (10) into equation (8) in consideration of the lowering of the stirring head yields:
in the formula, M Tubular pipe 1 Is the torque of the cutting blade;
calculating the torque of the blade:
in the formula, M Tubular pipe 1 Is the torque of the blade;
the torque between the stirring head and the soil is as follows:
M 2 ＝M tubular pipe 1 +kM Tubular pipe 2 (13)；
Substituting equation (11) and equation (12) into equation (13) yields:
further, the step of obtaining the loss power consumption of the mixing pile machine when the mixing head falls to the bottom end of each depth section and obtaining the loss power consumption corresponding to each depth section comprises:
determining a test point in the construction area, and determining the actual soil layer distribution in the design construction depth range below the test point to obtain a second soil layer type corresponding to each depth section;
constructing the test point through a mixing pile machine, acquiring power head information at preset acquisition time intervals, and recording the depth section where the mixing head is located as a target depth section when the mixing head descends to the bottom end of each depth section;
based on the physical and mechanical parameters of the second soil layer type, calculating the friction torque between the soil and the drill rod when the stirring head descends to the target depth section according to a formula (3), and calculating the torque between the stirring head and the soil when the stirring head descends to the target depth section according to a formula (4) and a formula (5);
based on the acquired power head information, calculating a second actual value of work of the power head on the stirring head in a period of time when the stirring head passes through the target depth section according to a first preset calculation rule;
calculating loss power consumption corresponding to the target depth section according to a formula (2) based on the calculated second actual value, the calculated friction torque between the soil and the drill rod and the calculated torque between the stirring head and the soil;
and obtaining the loss power consumption corresponding to each depth section based on the loss power consumption corresponding to the plurality of target depth sections.
Further, the step of determining the soil layer type of the target depth segment based on the first actual value and the calculated value corresponding to each first soil layer type includes:
and comparing the first actual value with the calculated value corresponding to each first soil layer type, and taking the first soil layer type corresponding to the calculated value closest to the first actual value as the soil layer type of the target depth section.
Compared with the prior art, the invention has the beneficial effects that:
(1) in the construction process, the work of the power head driving the stirring head to damage different soil layers is calculated layer by layer from top to bottom, the actual work of the power head is calculated according to the voltage value and the current value of the power head, the soil layer types corresponding to different depths are sequentially identified, and the accuracy of judging the soil layer types is improved;
(2) the method provides soil layer type division data for the targeted construction of each mixing pile, provides a basis for adjusting process parameters of each mixing pile, and can effectively improve the uniformity of the whole mixing pile and reduce the construction cost.
(3) Conventional stirring equipment all possesses corresponding data monitoring and collects the function, need not to increase other sensors to stirring equipment, can reduce construction cost.
Drawings
Fig. 1 is a flow chart of steps of the cement mixing pile soil layer identification method based on mixing energy consumption.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. The components of embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.
Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures. Meanwhile, in the description of the present invention, the terms "first", "second", and the like are used only for distinguishing the description, and are not to be construed as indicating or implying relative importance.
It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
In the description of the present invention, it should be noted that the terms "upper", "lower", "inside", "outside", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings or orientations or positional relationships conventionally put in use of products of the present invention, and are only for convenience of description and simplification of description, but do not indicate or imply that the devices or elements referred to must have specific orientations, be constructed in specific orientations, and be operated, and thus, should not be construed as limiting the present invention.
Referring to fig. 1, fig. 1 is a flowchart illustrating steps of a method for identifying a soil layer of a cement mixing pile based on mixing energy consumption according to the present invention.
A cement mixing pile soil layer identification method based on mixing energy consumption comprises the following steps:
s1, surveying the construction area, determining a plurality of first soil layer types contained in the construction area, and acquiring physical and mechanical parameters of each first soil layer type;
s2, obtaining a design construction depth, and dividing the design construction depth into a plurality of depth sections;
s3, before construction, obtaining the loss power consumption of the mixing pile machine when the mixing head descends to the bottom end of each depth section, and obtaining the loss power consumption corresponding to each depth section;
s4, in the construction process, acquiring power head information every other preset acquisition time, and recording the depth section where the stirring head is located as a target depth section when the stirring head descends to the bottom end of each depth section, wherein the power head information comprises a voltage value and a current value of the power head;
s5, based on the acquired power head information, calculating a first actual value of work of the power head on the stirring head in a period of time when the stirring head passes through a target depth section according to a first preset calculation rule;
s6, calculating calculated values of work done by the power head to the stirring head in a period of time when the soil layer type of the target depth section is assumed to be various first soil layer types according to a second preset calculation rule based on physical and mechanical parameters of various first soil layer types and the loss power consumption corresponding to the target depth section, and obtaining calculated values corresponding to the first soil layer types;
and S7, determining the soil layer type of the target depth section based on the first actual value and the calculated value corresponding to each first soil layer type.
In the step S1, the soil layer distribution in the construction area is surveyed by a drilling survey method, it is determined that there are several soil layer types in the construction area, the soil layer types are recorded as first soil layer types to obtain a plurality of first soil layer types included in the construction area, and then the physical mechanical parameters of each first soil layer type are tested to obtain the physical mechanical parameters corresponding to each first soil layer type.
In the step S2, the design construction depth is the length of the mixing pile, the design construction depth is divided into a plurality of depth sections, the setting of the depth sections can be determined according to the required identification precision, generally, soil layers smaller than 0.5 m in the geotechnical investigation are not divided into soil layer types alone, that is, even if there are two different soils within the range of 0.5 m, the soil layers are treated as one soil layer type in practical application, so the depth sections should not be smaller than 0.5 m. In this embodiment, the depth segment is taken to be 0.5 meters.
In the step S3, the power head drives the drill rod and the stirring head to rotate, so that in the process of descending the stirring head, the power head generates heat and friction is generated between the drill rod and the pile gripper, thereby causing power loss, and the power head generates heat and the friction loss between the drill rod and the pile gripper can be the loss power consumption of the mixing pile machine, so that before soil layer identification, the loss power consumption of the mixing pile machine when the stirring head descends to the bottom end of each depth section is obtained first, and is used for subsequent calculation.
Further, the physical and mechanical parameters include cohesive force, friction angle, gravity, friction coefficient and lateral pressure coefficient, and in step S3, the step of obtaining the loss power consumption of the mixing pile machine when the mixing head descends to the bottom end of each depth section includes:
s31, determining a test point in the construction area, and determining the actual soil layer distribution in the design construction depth range below the test point to obtain a second soil layer type corresponding to each depth section;
s32, constructing the test point through the mixing pile machine, acquiring power head information every preset acquisition time, and recording the depth section where the mixing head is located as a target depth section when the mixing head descends to the bottom end of each depth section;
s33, calculating friction torque between the soil and the drill rod when the stirring head descends to a target depth section according to a formula (3) based on physical and mechanical parameters of the type of the second soil layer, and calculating torque between the stirring head and the soil when the stirring head descends to the target depth section according to a formula (4) and a formula (5);
s34, calculating a second actual value of work of the power head on the stirring head in a period of time when the stirring head passes through the target depth section according to the first preset calculation rule based on the acquired power head information;
s35, calculating loss power consumption corresponding to the target depth section according to a formula (2) based on the calculated second actual value, the calculated friction torque between the soil and the drill rod and the calculated torque between the stirring head and the soil;
and S36, obtaining the loss power consumption corresponding to each depth section based on the loss power consumption corresponding to the target depth sections.
In the step S31, since it is determined in the construction area that there are several soil layer types in the construction area by the drilling reconnaissance method in the step S1, the test point may select a drilling position of the drilling reconnaissance method, and therefore, the actual soil layer distribution is divided at the test point by taking out soil samples at different depths from the test point due to the reconnaissance hole, that is, the actual soil layer types corresponding to each depth section below the test point may be obtained, and the actual soil layer types are recorded as the second soil layer type, and at the same time, physical and mechanical parameters of the second soil layer type may also be obtained by testing.
In the step S32, a mixing pile machine is used to construct the test point, the rotation speed is kept constant during the construction process, and then the voltage value and the current value of the power head are obtained every preset acquisition time, preferably, the preset acquisition time may be 5S. And in the construction process, the depth sections can be sequenced and numbered according to the depth, for example, in the construction process, according to the elevation information acquired by the mixing pile machine, when the mixing head descends to a position 0.5 meter below the ground, namely the mixing head descends to the bottom end of the first depth section, the first depth section is recorded as a target depth section, then the mixing head continuously descends to a position 1 meter below the ground, namely the mixing head descends to the bottom end of the second depth section, the second depth section is recorded as a target depth section, and therefore through the continuous descending of the mixing head, the depth sections are sequentially recorded as the target depth sections.
In the step S33, since the actual soil layer distribution within the designed construction depth range below the test point is known, when the stirring head descends to the bottom end of the target depth section, the number of the upper soil layers above the target depth section and the soil layer types corresponding to the upper soil layers can be known according to the second soil layer type corresponding to each depth section, and meanwhile, the vertical effective stress σ of the soil body of each upper soil layer can be known zi Lateral pressure coefficient mu of earth si Thickness h of the mixed soil i And the diameter d of the drill rod can be directly measured, thus according to the formula (3)
Calculating the friction torque M of the soil and the drill rod when the stirring head descends to the target depth section 1 In the formula, M 1 Is the friction torque of soil and drill pipe, d is the diameter of drill pipe, and n' is above the target depth sectionNumber of layers of overburden, sigma zi The vertical effective stress k of the soil body of the soil layer covering the ith layer si Is the lateral pressure coefficient of the soil of the overburden layer on the ith layer, mu si The friction coefficient h between the soil of the soil layer covering the ith layer and the drill rod i The thickness of the covering soil layer on the ith layer.
And similarly, obtaining the overburden pressure sigma above the target depth section according to the number of the overburden above the target depth section, the actual soil type of each overburden, the thickness of each overburden and the gravity of each overburden, wherein if the construction area is below the water surface, the overburden pressure sigma above the target depth section is added with the water pressure, and the water pressure is equal to the gravity of the water multiplied by the depth of the water. Specifically, taking the construction area below the water surface as an example, the overburden pressure σ above the target depth section is calculated by the following formula:
in the formula, gamma Water (W) Is the gravity of water, h Water (W) Is the depth of water, n' is the number of overburden layers above the target depth section, gamma Soil i Is the weight of the topsoil layer on the ith layer, h Soil i The thickness of the overburden layer on the ith layer is shown, wherein i is 1, 2, … … and n'.
Obtaining the cohesive force c and the friction angle according to the type of the second soil layer corresponding to the target depth section
Thus according to formula (4)
Calculating the shearing strength of the second soil layer type corresponding to the target depth section when the stirring head descends to the target depth section, wherein c u C is the cohesive force of the second soil layer type corresponding to the target depth section,
second soil corresponding to the target depth sectionThe layer type friction angle, σ, is the overburden pressure above the target depth section.
Then, according to the soil sensitivity of the type of the second soil layer corresponding to the target depth section, the size and the layer number of the cutting blade and the blade on the stirring head are combined according to a formula (5)
Calculating the torque M between the stirring head and the soil of the second soil layer type corresponding to the target depth section when the stirring head descends to the target depth section 2 In the formula, M 2 For the torque between the stirring head and the soil,/ 1 Length of cutting blade, B 1 Width of cutting blade, theta 1 For the angle of inclination of the cutting blade, V Through tube For the head descent speed, n for the head rotation speed, S t For soil sensitivity, k is the number of leaf layers, l 2 Is the length of the blade, B 2 Is the width of the blade, theta 2 Is the pitch angle of the blade.
In step S34, in step S32, the voltage and current values of the power heads are obtained at preset collection time intervals to obtain information of a plurality of power heads, and the time and the elevation are generally recorded during the descending process of the mixing head, so that the information of the power heads obtained during the period from the top end of the target depth section to the bottom end of the target depth section can be marked as target power head information, and then the target power head information is obtained according to the formula (1)
Calculating a first actual value W of the work of the power head on the stirring head passing through the target depth section Fruit of Chinese wolfberry U is the voltage value of the power head, and the voltage value of the general power head is a stable value, for example, in one embodiment, the voltage value of the power head is 380V, n' is the number of power head information obtained during the period of time that the stirring head passes through the target depth zone, I i The current value i in the ith power head information acquired for the time when the stirring head passes through the target depth section1. 2, … …, n ", t is the preset acquisition time.
In the step S35, the work performed by the power head to the stirring head in the period of time passing through the target depth is mainly used for heating the power head, rotating the drill rod, overcoming friction and cutting to destroy the soil, and the formula (2) W Meter ＝W Consumption unit +(M 1 +M 2 ) nt' 2 π change to W Consumption unit ＝W Meter -(M 1 +M 2 ) nt' 2 pi, friction torque M of the soil and the drill rod obtained in the step S33 1 And a torque M between the mixing head and the soil of the second soil layer type corresponding to the target depth section 2 And a first actual value W of the work performed by the power head on the agitator head over the target depth period obtained in step S34 Fruit of Chinese wolfberry The loss power consumption of the mixing pile machine when the mixing head descends to the bottom end of the target depth section can be obtained by substituting the formula, and therefore the loss power consumption corresponding to the target depth section is obtained.
In the step S36, while the mixing head is lowered to the designed construction depth, the power loss corresponding to the target depth steps, i.e., the power loss corresponding to each depth step, is sequentially calculated from the step S33 to the step S35.
In the step S4, the multiple depth segments are sorted and numbered according to depth, then a mixing pile machine is used to construct the pre-marked pile position in the construction area, the rotation speed is kept constant during the construction process, the voltage value and the current value of the power head are obtained every preset acquisition time to obtain multiple pieces of power head information, and during the construction process, according to the elevation information obtained by the mixing pile machine, when the mixing head descends to a position 0.5 meter below the ground, that is, the mixing head descends to the bottom end of the first depth segment, the first depth segment is marked as a target depth segment, then the mixing head descends to a position 1 meter below the ground, that is, the mixing head descends to the bottom end of the second depth segment, the second depth segment is marked as a target depth segment, and thus the multiple depth segments are sequentially marked as target depth segments through the continuous descending of the mixing head. And then calculating the driving torque for damaging each soil layer type when the stirring head is in the target depth section according to a preset calculation rule based on the physical and mechanical parameters of each soil layer type and the friction torque corresponding to the target depth section.
In step S5, each time the tool bit is lowered from the top end of the target depth zone to the bottom end of the target depth zone, a first actual value of work performed by the tool bit on the tool bit for a period of time during which the tool bit is lowered from the top end of the target depth zone to the bottom end of the target depth zone is calculated according to a first calculation rule set in advance based on the acquired information of the tool bit.
Further, in step S5, the step of calculating a first actual value of the work performed by the power head on the stirring head during the period of time passing through the target depth according to a first preset calculation rule includes:
s51, calculating a first actual value of the work of the power head on the stirring head in the period of time when the stirring head passes through the target depth according to the following formula:
in the formula, W Fruit of Chinese wolfberry A first actual value of work done by the power head to the stirring head in a period of time passing through a target depth section, U is a voltage value of the power head, n' is the number of pieces of power head information acquired in a period of time passing through the target depth section, and I i And the current value in the ith power head information acquired by the stirring head in the time period of passing through the target depth segment is i-1, 2, … …, n ", and t is the preset acquisition time.
In the step S51, the work done by the power head is calculated once every preset collection time, and the time and the elevation are generally recorded during the descending process of the stirring head, so that the work done by the power head calculated during the time period when the stirring head descends from the top end of the target depth section to the bottom end of the target depth section is added to obtain the first actual value W of the work done by the power head to the stirring head during the time period when the stirring head passes through the target depth section Fruit of Chinese wolfberry 。
In the step S6, the multiple first soil layer types included in the construction area are determined in the step S1, and the soil layer types corresponding to the target depth section are sequentially assumed as each first soil layer type, so that when the soil layer types of the target depth section are calculated according to the second preset calculation rule, the calculated value of the work performed by the power head on the stirring head during the period when the stirring head passes through the target depth section is calculated, and the calculated value corresponding to each first soil layer type is obtained.
Further, the physical and mechanical parameters comprise cohesive force, friction angle, gravity, friction coefficient and lateral pressure coefficient; in step S6, when the soil layer type of the target depth section is assumed to be the first soil layer type, the step of calculating the calculated value of the work performed by the power head on the stirring head during the period of time when the stirring head passes through the target depth section according to the second preset calculation rule includes:
s61, sequentially selecting a target soil layer type from the multiple first soil layer types, and calculating a calculated value of work of the power head on the stirring head in a period of time when the soil layer type of the target depth section is assumed to be the target soil layer type according to the following formula:
W meter ＝W Consumption unit +(M 1 +M 2 )nt′2π (2)
In the formula, W Meter When the soil layer type of the target depth section is assumed to be the first soil layer type, the power head calculates the work of the stirring head in the period of time of passing through the target depth section, W Consumption unit The loss power corresponding to the target depth section, t' is the time of the stirring head passing through the target depth section, M 1 The friction torque of soil and the drill rod, d is the diameter of the drill rod, n' is the number of layers of the overburden layer above the target depth section, and sigma zi The vertical effective stress k of the soil body of the soil layer covering the ith layer si Covering the ith layer with a soil layerLateral pressure coefficient of earth, mu si The friction coefficient h between the soil of the soil layer covering the ith layer and the drill rod i Thickness of the topsoil layer of the i-th layer, c u C is the cohesion of the first soil layer type assumed for the target depth segment,
a friction angle of the first soil layer type assumed for the target depth segment, σ is overburden pressure above the target depth segment, M 2 For the torque between the stirring head and the soil,/ 1 Length of cutting blade, B 1 Width of cutting blade, theta 1 For the angle of inclination of the cutting blade, V Through the tube For the head descent speed, n for the head rotation speed, S t For soil sensitivity, k is the number of leaf layers, l 2 Is the length of the blade, B 2 Is the width of the blade, theta 2 Is the pitch angle of the blade.
In step S61, when the stirring head descends to the target depth section, the soil layer types of the depth section above the target depth section are identified and known, and the soil layer type corresponding to the target depth section is unknown, so that one target soil layer type is sequentially selected from the multiple first soil layer types, the target soil layer type is assumed as the soil layer type of the target depth section, thereby determining the number of soil layer types in contact with the drill rod, and determining the soil body vertical effective stress σ of each soil layer type zi Lateral pressure coefficient k of earth si Coefficient of friction mu between soil and drill rod si And thickness of soil, thereby M according to formula (3) 1 ＝d·
Calculating to obtain the friction torque M of the soil and the drill rod when the soil layer type corresponding to the target depth section is the target soil layer type and the stirring head descends to the target depth section 1 . And similarly, the number of the overlying soil layers above the target depth section, the soil layer type of each overlying soil layer, the thickness of each overlying soil layer and the gravity of each overlying soil layer are used to obtain the overlying soil layer pressure sigma above the target depth section, and the target soil corresponding to the target depth sectionLayer type can give cohesion c and friction angle
Thus according to formula (4)
Calculating the shear strength of the target soil layer type when the soil layer type corresponding to the target depth section is the target soil layer type and the stirring head descends to the target depth section, and then combining the soil sensitivity of the target soil layer type with the cutting blade at the bottom end of the stirring head and the size and the number of layers of the blades on the outer side wall of the stirring head according to a formula (5)
Calculating to obtain the torque M between the stirring head and the soil of the target soil layer type when the soil layer type corresponding to the target depth section is the target soil layer type and the stirring head descends to the target depth section 2 . According to the corresponding loss power consumption W of the target depth section Consumption unit W according to formula (2) Meter ＝W Consumption unit +(M 1 +M 2 ) And calculating nt' 2 pi to obtain a calculated value of work of the power head on the period of time when the soil layer type corresponding to the target depth section is the target soil layer type and the stirring head descends to the target depth section.
Further, in step S61, the derivation process of equation (5) is as follows:
according to the cross plate shear test principle, the torque can be divided into two parts, one part is used for overcoming the soil shear strength of the side surface formed into a cylindrical surface, and the other part is used for overcoming the soil shear strength of the top surface and the bottom surface formed into a ring, so that the torque is obtained:
in formula (II) to' 1 For overcoming the moment, M ', required for the shear strength of the cylindrical soil mass' 2 The moment required for overcoming the shear strength of the top surface soil body and the bottom surface soil body, M is the total moment for overcoming the shear strength of the soil body, d is the diameter of the drill rod, l is the length of the blade or the length of the cutting blade, B is the width of the blade or the width of the cutting blade, and theta is the blade inclination angle or the cutting blade inclination angle;
in the work progress, in the soil body that cutting blade stirring destroyed, the soil body of cutting blade bottom destruction is original state soil, and when cutting blade upper portion got into the soil body stirring, the soil body was the disturbed soil of stirring through cutting blade bottom, and consequently the relation that cutting blade stirring destroyed the soil body does:
h 1 ＝B 1 sinθ 1 -h 2 (10)
in the formula, h 2 Thickness of undisturbed soil for cutting blade stirring, h 1 Thickness of disturbed soil for cutting blade agitation;
considering the condition that the stirring head descends, mixing 1 And h 2 Substituting into formula (8) and considering the soil sensitivity after soil layer construction disturbance to obtain:
substituting equation (9) and equation (10) into equation (14) yields:
in the formula, M Tubular pipe 1 Is the torque of the cutting blade;
the soil body of blade stirring cutting all is the disturbed soil after the cutting blade stirring, consequently need consider the soil body sensitivity after the soil layer construction disturbance, calculates the moment of torsion of blade:
in the formula, M Tubular pipe 1 Is the torque of the blade;
the torque between the stirring head and the soil is as follows:
M 2 ＝M tubular pipe 1 +kM Tubular pipe 2 (13)；
Substituting equation (11) and equation (12) into equation (13) yields:
in step S7, when the soil type corresponding to the target depth segment is the target soil type and the stirring head descends to the target depth segment, the one-to-one correspondence relationship between the plurality of first soil types and the plurality of calculated values in the target depth segment can be obtained by using the calculated value of the work performed by the power head in the period when the stirring head passes through the target depth segment, and then the soil type corresponding to the target depth segment can be determined by comparing the first actual value with the plurality of calculated values by using the first actual value of the work performed by the power head in the period when the stirring head passes through the target depth segment. Therefore, when the stirring head descends to the designed construction depth, the soil layer types of different depth sections can be sequentially confirmed from top to bottom, so that the soil layer types of all the depth sections can be obtained, and the identification of the stirring pile construction soil layer is realized.
Further, in step S7, the step of determining the soil layer type of the target depth segment based on the first actual value and the calculated value corresponding to each first soil layer type includes:
and S71, comparing the first actual value with the calculated value corresponding to each first soil layer type, and taking the first soil layer type corresponding to the calculated value closest to the first actual value as the soil layer type of the target depth section.
In step S71, the absolute values of the differences between the calculated values and the first actual value are calculated respectively, and then the absolute values of the obtained differences are compared to obtain the absolute value of the smallest difference, that is, the calculated value closest to the first actual value is the target calculated value, where the first actual value is closest to the target calculated value, which indicates that the difference between the work performed by the power head on the stirring head through the actual soil layer and the work performed by the stirring head through the first soil layer type corresponding to the target calculated value is not large, that is, the soil layer type of the actual soil layer of the target depth section where the stirring head is located can be regarded as the first soil layer type corresponding to the target calculated value, and thus the soil layer type of the target depth section can be determined.
Compared with the prior art, the invention has the beneficial effects that:
(1) in the construction process, the work of the power head driving the stirring head to damage different soil layers is calculated layer by layer from top to bottom, the actual work of the power head is calculated according to the voltage value and the current value of the power head, the soil layer types corresponding to different depths are sequentially identified, and the accuracy of judging the soil layer types is improved;
(2) the method provides soil layer type division data for the targeted construction of each mixing pile, provides a basis for adjusting process parameters of each mixing pile, and can effectively improve the uniformity of the whole mixing pile and reduce the construction cost.
(3) Conventional stirring equipment all possesses corresponding data monitoring and collects the function, need not to increase other sensors to stirring equipment, can reduce construction cost. The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention in any way, so that any simple modification, equivalent change and modification made to the above embodiment according to the technical spirit of the present invention will still fall within the scope of the technical solution of the present invention without departing from the content of the technical solution of the present invention.
Claims (6)
1. A cement mixing pile soil layer identification method based on mixing energy consumption is characterized by comprising the following steps:
surveying a construction area, determining a plurality of first soil layer types contained in the construction area, and acquiring physical and mechanical parameters of each first soil layer type;
obtaining a design construction depth, and dividing the design construction depth into a plurality of depth sections;
before construction, obtaining the loss power consumption of the mixing pile machine when the mixing head descends to the bottom end of each depth section, and obtaining the loss power consumption corresponding to each depth section;
in the construction process, power head information is obtained at intervals of preset acquisition time, and when the stirring head descends to the bottom end of each depth section, the depth section where the stirring head is located is marked as a target depth section, wherein the power head information comprises a voltage value and a current value of the power head;
based on the acquired power head information, calculating a first actual value of work of the power head on the stirring head in a period of time when the stirring head passes through a target depth section according to a first preset calculation rule;
based on physical and mechanical parameters of multiple first soil layer types and the loss power consumption corresponding to the target depth section, calculating a calculated value of work of the power head on the stirring head passing through the target depth section in a period of time when the soil layer type of the target depth section is assumed to be the first soil layer type according to a second preset calculation rule, and obtaining a calculated value corresponding to each first soil layer type;
and determining the soil layer type of the target depth section based on the first actual value and the calculated value corresponding to each first soil layer type.
2. The method for identifying the soil layer of the cement mixing pile based on the mixing energy consumption as claimed in claim 1, wherein the step of calculating the first actual value of the work of the power head on the period of time that the mixing head passes through the target depth section according to the first preset calculation rule comprises:
calculating a first actual value of the work performed by the power head on the agitator head over the period of time through the target depth interval according to the following formula:
in the formula, W Fruit of Chinese wolfberry A first actual value of work done by the power head to the stirring head in a period of time passing through a target depth section, U is a voltage value of the power head, n' is the number of pieces of power head information acquired in a period of time passing through the target depth section, and I i And the current value in the ith power head information acquired when the stirring head passes through the target depth section is 1, 2, … …, n' and t is the preset acquisition time.
3. The cement mixing pile soil layer identification method based on mixing energy consumption of claim 1, wherein the physical and mechanical parameters comprise cohesion, friction angle, gravity, friction coefficient and lateral pressure coefficient;
the step of calculating the calculated value of the work of the power head on the stirring head in the period of time when the soil layer type of the target depth section is assumed to be various first soil layer types according to the second preset calculation rule comprises the following steps:
sequentially selecting a target soil layer type from the multiple first soil layer types, and calculating a calculated value of work of the power head on the stirring head in a period of time when the soil layer type of the target depth section is assumed to be the target soil layer type according to the following formula:
W meter ＝W Consumption unit +(M 1 +M 2 )nt′2π (2)
In the formula, W Meter When the soil layer type of the target depth section is assumed to be the first soil layer type, the power head calculates the work of the stirring head in the period of time of passing through the target depth section, W Consumption of The corresponding power loss for the target depth segment, t' is the time for the stirrer head to pass through the target depth segment, M 1 The friction torque of soil and the drill rod, d is the diameter of the drill rod, n' is the number of layers of the overburden layer above the target depth section, and sigma zi The vertical effective stress k of the soil body of the soil layer covering the ith layer si Is the lateral pressure coefficient of the soil of the overburden layer on the ith layer, mu si The friction coefficient h between the soil of the soil layer covering the ith layer and the drill rod i Thickness of the topsoil layer of the i-th layer, c u C is the cohesion of the first soil layer type assumed for the target depth segment,
a friction angle of the first soil layer type assumed for the target depth segment, σ is overburden pressure above the target depth segment, M 2 For the torque between the stirring head and the soil,/ 1 Length of cutting blade, B 1 Width of cutting blade, theta 1 For the angle of inclination of the cutting blade, V Through tube For the head descent speed, n for the head rotation speed, S t For soil sensitivity, k is the number of leaf layers, l 2 Is the length of the blade, B 2 Is the width of the blade, theta 2 Is the pitch angle of the blade.
4. The method for identifying the soil layer of the cement mixing pile based on the mixing energy consumption as claimed in claim 3, wherein the derivation process of the formula (5) is as follows:
according to the principle of a cross plate shear test, the method comprises the following steps:
in formula (II) to' 1 For overcoming the moment, M ', required for the shear strength of the cylindrical soil mass' 2 The moment required for overcoming the shear strength of the top surface soil body and the bottom surface soil body, M is the total moment for overcoming the shear strength of the soil body, d is the diameter of the drill rod, l is the length of the blade or the length of the cutting blade, B is the width of the blade or the width of the cutting blade, and theta is the blade inclination angle or the cutting blade inclination angle;
in the construction process, the relation that the cutting blade stirs and destroys the soil body is as follows:
h 1 ＝B 1 sinθ 1 -h 2 (10)
in the formula, h 2 Thickness of undisturbed soil for cutting blade stirring, h 1 Thickness of disturbed soil for cutting blade agitation;
substituting equation (9) and equation (10) into equation (8) in consideration of the lowering of the stirring head yields:
in the formula, M Tubular pipe 1 Is the torque of the cutting blade;
calculating the torque of the blade:
in the formula, M Tubular pipe 1 Is the torque of the blade;
the torque between the stirring head and the soil is as follows:
M 2 ＝M tubular pipe 1 +kM Tubular pipe 2 (13)；
Substituting equation (11) and equation (12) into equation (13) yields:
5. the method for identifying the soil layer of the cement mixing pile based on the mixing energy consumption as claimed in claim 1, wherein the step of obtaining the loss power consumption of the mixing pile machine when the mixing head descends to the bottom end of each depth section to obtain the loss power consumption corresponding to each depth section comprises:
determining a test point in the construction area, and determining actual soil layer distribution in a design construction depth range below the test point to obtain a second soil layer type corresponding to each depth section;
constructing a test point through the mixing pile machine, acquiring the power head information at preset acquisition time intervals, and recording the depth section where the mixing head is located as a target depth section when the mixing head descends to the bottom end of each depth section;
based on the physical and mechanical parameters of the second soil layer type, calculating the friction torque between the soil and the drill rod when the stirring head descends to a target depth section according to a formula (3), and calculating the torque between the stirring head and the soil when the stirring head descends to the target depth section according to a formula (4) and a formula (5);
based on the acquired power head information, calculating a second actual value of work of the power head on the stirring head in a period of time when the stirring head passes through a target depth section according to the first preset calculation rule;
calculating loss power consumption corresponding to the target depth section according to a formula (2) based on the calculated second actual value, the calculated friction torque between the soil and the drill rod and the calculated torque between the stirring head and the soil;
and obtaining the loss power consumption corresponding to each depth section based on the loss power consumption corresponding to the target depth sections.
6. The method for identifying the soil layer of the cement mixing pile based on the mixing energy consumption as claimed in claim 1, wherein the step of determining the soil layer type of the target depth segment based on the first actual value and the calculated value corresponding to each first soil layer type comprises:
and comparing the first actual value with the calculated value corresponding to each first soil layer type, and taking the first soil layer type corresponding to the calculated value closest to the first actual value as the soil layer type of the target depth section.
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