Dynamic compaction effective reinforcement depth calculation method and system

Abstract

The invention belongs to the technical field of foundation treatment, and discloses a dynamic compaction effective reinforcement depth calculation method and method.The method comprises the steps that the dry density of soil layers every preset depth before dynamic compaction construction of a construction site is obtained; obtaining an actual measurement result of the effective reinforcement depth of dynamic compaction after trial compaction and dry density of soil layers at intervals of preset depth after trial compaction; determining the average dry density of the soil layers before dynamic compaction construction and the average dry density of the soil layers after the dynamic compaction according to the dry density of the soil layers every preset depth before the dynamic compaction construction of the construction site and the dry density of the soil layers every preset depth after the dynamic compaction test on the basis of the actual measurement result of the effective reinforcement depth of the dynamic compaction after the dynamic compaction test; the compaction settlement after formal dynamic compaction construction is obtained; according to the average dry density of the soil layer before dynamic compaction construction, the average dry density of the soil layer after compaction and the compaction settlement after formal dynamic compaction construction, the calculation result of the dynamic compaction effective reinforcement depth of the construction site is obtained through calculation; the calculation process is simple, and the randomness and deviation of the calculation result of the dynamic compaction effective reinforcement depth are reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of foundation treatment, and in particular relates to a method and system for calculating the effective reinforcement depth of strong tamping. Background Art

[0002] In the process of foundation treatment, dynamic compaction method is generally used for reinforcement and improvement. Dynamic compaction method has different improvement purposes for foundations of different soil types. For example, in the improvement of collapsible loess foundation, its main purpose is to destroy the macropore structure of loess, compact the loess soil, and then eliminate the collapsible property of the soil. In the improvement of saturated sand foundation, its main purpose is to improve the relative density of the soil to improve its resistance to liquefaction. For general soft clay foundation, its main purpose is to improve the strength of the soil and reduce soil deformation.

[0003] Among them, the effective reinforcement depth of dynamic tamping is an important design parameter of the dynamic tamping method. It is not only an important basis for selecting the dynamic tamping method, but also an important parameter reflecting the effect of dynamic tamping treatment. According to the requirements of relevant specifications, foundation soil is generally divided into two categories: coarse-grained soil and fine-grained soil, and the estimated values ​​of the effective reinforcement depth of dynamic tamping under different dynamic tamping energy levels are listed, which is simple and practical. However, in actual projects, it is shown that the existing specifications have large errors, and there is no regulation for dynamic tamping with energy levels above 12000kN·m. Secondly, the factors affecting the effective reinforcement depth of dynamic tamping mainly include tamping energy, soil properties, construction quality and dynamic tamping methods. Among them, tamping energy is related to hammer weight, hammer diameter, tamping hammer drop distance and tamping equipment. The properties of soil are related to soil classification, moisture content, porosity, dry density and permeability. The properties of soil in different engineering locations are often very different. The construction quality and method are even more difficult to accurately control. Therefore, the actual effective reinforcement depth of dynamic tamping generally needs to be determined through on-site tamping tests or local experience.

[0004] At present, when determining the effective reinforcement depth of strong compaction through on-site trials or local experience, some scholars have summarized a series of positive coefficients of Menachew's formula based on engineering practice. However, the above coefficients are often highly empirical and are still difficult to estimate accurately for different projects. In addition, there are also methods that determine the effective reinforcement depth of strong compaction through empirical formulas or simplified theoretical analysis methods.

[0005] Specifically, the empirical formula method can be subdivided into empirical formula methods based on engineering practice results, indoor model tests, and field observation results; since the empirical formula method has a simple calculation process and is easy to use, it takes factors such as soil properties, construction machinery and construction quality into account through correction coefficients, greatly improving the calculation efficiency; but the correction coefficient needs to be obtained through a large amount of field measured data, and has a certain degree of randomness. Since the soil layers in the same area are often quite different, it is also necessary to combine the field measured data when using it to accurately calculate the effective reinforcement depth, which makes the process complicated and the results have large deviations.

[0006] The simplified theoretical analysis method attempts to establish a predictive evaluation formula for the compaction effect from an analytically based theoretical analysis, which is mainly used to evaluate the effective reinforcement depth. There are two main types of such methods: one is to determine the stress on the hammer-soil contact surface by theories or experiments such as dynamic principles, use the elastic statics formula to solve the diffusion of dynamic stress, and define the effective reinforcement depth by the depth at which the additional stress reaches a certain critical value, which can be called the stress method; the other is to derive the calculation formula for the effective reinforcement depth from the propagation and consumption laws of shock waves and energy, which can be called the energy method; since the calculation methods of the simplified theoretical analysis, namely the energy conservation method and the equivalent quasi-static method, need to derive the calculation formula through the study of the mechanism of compaction, the calculation process is often complicated and lacks actual engineering verification.

[0007] In summary, the existing method for determining the effective reinforcement depth of dynamic compaction is random and the calculation process is cumbersome, and the estimation results of the effective reinforcement depth of dynamic compaction have large deviations. Summary of the invention

[0008] In view of the technical problems existing in the prior art, the present invention provides a method and system for calculating the effective reinforcement depth of dynamic tamping, so as to solve the problems that the existing method for determining the effective reinforcement depth of dynamic tamping is random, the calculation process is cumbersome, and the estimation results of the effective reinforcement depth of dynamic tamping have large deviations.

[0009] In order to achieve the above object, the technical solution adopted by the present invention is:

[0010] The present invention provides a method for calculating the effective reinforcement depth of dynamic compaction, comprising:

[0011] Get the dry density ρ of the soil layer at each preset depth before the construction site compaction di ;

[0012] Obtain the measured result L of the effective reinforcement depth of strong compaction after the test compaction s And the dry density of the soil layer at each preset depth after the test tamping ρ sdi ;

[0013] Based on the measured results of the effective reinforcement depth of strong compaction after the test compaction, L s , according to the dry density ρ of the soil layer at each preset depth before the strong compaction construction of the construction site di and the dry density ρ of the soil layer at each preset depth after the test tamping sdi , determine the average dry density ρ of the soil layer before dynamic compaction construction d1 and the average dry density of the soil layer after tamping ρ d2 ;

[0014] Obtain the tamping settlement amount d after the formal dynamic tamping construction;

[0015] According to the average dry density of the soil layer before the dynamic compaction construction, ρd1 , the average dry density of the rammed soil layer ρ d2 The effective reinforcement depth of the construction site by dynamic compaction is calculated based on the amount of compaction settlement d after the formal dynamic compaction construction.

[0016] Furthermore, the dry density ρ of the soil layer at each preset depth before the construction site compaction is obtained. di The process is as follows:

[0017] From the geological survey data of the construction site, record the dry density data of each preset depth of the soil layer at the construction site, that is, the dry density ρ of each preset depth of the soil layer at the construction site before the strong compaction construction is obtained. di .

[0018] Furthermore, the measured result L of the effective reinforcement depth of the strong compaction after the test compaction is obtained. s And the dry density of the soil layer at each preset depth after the test tamping ρ sdi The process is as follows:

[0019] According to the predetermined dynamic compaction construction plan, test compaction is carried out in the corners of the construction site. After the test compaction, the original soil samples of each preset depth are obtained by drilling or excavating a well. Based on the original soil samples of each preset depth, the measured results of the effective reinforcement depth of dynamic compaction after the test compaction are obtained. s And the dry density of the soil layer at each preset depth after the test tamping ρ sdi .

[0020] Furthermore, based on the measured results of the effective reinforcement depth of the strong compaction after the test, L s , according to the dry density ρ of the soil layer at each preset depth before the strong compaction construction of the construction site di and the dry density ρ of the soil layer at each preset depth after the test tamping sdi , determine the average dry density ρ of the soil layer before dynamic compaction construction d1 and the average dry density of the soil layer after tamping ρ d2 The process is as follows:

[0021] According to the dry density ρ of the soil layer at each preset depth before the strong compaction construction of the construction site di And the dry density ρ of the soil layer at each preset depth after the test tamping sdi , and obtain the calculation results of the effective reinforcement depth of strong compaction after several tamping tests L si ;

[0022] The calculation results of the effective reinforcement depth of the strong tamping after several test tamping are L si The measured result of the effective reinforcement depth after the test tamping is L s By comparison, the measured result L of the effective reinforcement depth after the test tamping is determined.s The calculation result of the effective reinforcement depth of the closest test tamping is used to obtain the depth L of the average dry density of the soil layer. q ;

[0023] According to the soil layer average dry density value depth L q And the dry density ρ of the soil layer at each preset depth before the strong compaction construction of the construction site di , the average dry density of the soil layer before compaction construction is calculated d1 ;

[0024] According to the soil layer average dry density value depth L q And the dry density ρ of the soil layer at each preset depth after the test tamping sdi , the average dry density of the soil layer after tamping is calculated d2 .

[0025] Furthermore, the calculation results of the effective reinforcement depth L after several tamping tests are si The calculation process is as follows:

[0026]

[0027] Among them, L si is the calculation result of the effective reinforcement depth of strong compaction after trial compaction; d i is the tamping amount after the test; ρ di ρ is the dry density of the soil layer at each preset depth before the construction site is compacted; sdi It is the dry density of soil layer at each preset depth after test compaction.

[0028] Furthermore, according to the soil layer average dry density value depth L q And the dry density ρ of the soil layer at each preset depth before the strong compaction construction of the construction site di , the average dry density of the soil layer before compaction construction is calculated d1 The process is as follows:

[0029] The dry density ρ of the soil layer at each preset depth before the strong compaction construction at the construction site di In the above example, the depth L of the soil layer average dry density is selected. q Dry density of soil layers at different depths before compaction to the original ground;

[0030] The depth L of the soil layer average dry density q The dry density of soil layers at different depths before compaction construction between the ground and the ground is summed and the average value is taken, that is, the average dry density of the soil layer before compaction construction ρ d1 .

[0031] Furthermore, according to the soil layer average dry density value depth L q And the dry density ρ of the soil layer at each preset depth after the test tamping sdi , the average dry density of the soil layer after tamping is calculated d2 The process is as follows:

[0032] The dry density ρ of the soil layer at each preset depth after the test tamping sdi In the above example, the depth L of the soil layer average dry density is selected. q Dry density of soil layers at different depths after tamping test to the ground after tamping test;

[0033] The depth L of the soil layer average dry density q The dry density of soil layers at different depths after tamping is summed and the average value is taken, that is, the average dry density of the soil layer after tamping is obtained. d2 .

[0034] Furthermore, the process of obtaining the tamping settlement amount d after the formal dynamic tamping construction is as follows:

[0035] Obtain the ground elevation of the construction site before and after the compaction;

[0036] According to the ground elevation before the dynamic compaction construction and the ground elevation after the formal dynamic compaction construction of the construction site, the tamping amount d after the formal dynamic compaction construction is calculated.

[0037] Furthermore, the calculation process of the calculation result of the effective reinforcement depth of the construction site by compaction is as follows:

[0038]

[0039] Wherein, L1 is the calculation result of the effective reinforcement depth of the construction site by dynamic compaction, d is the tamping amount after the formal dynamic compaction construction; ρ d1 is the average dry density of the soil layer before dynamic compaction construction; ρ d2 is the average dry density of the soil layer after tamping.

[0040] The present invention also provides a system for calculating the effective reinforcement depth of dynamic compaction, comprising:

[0041] The module for obtaining dry density before compaction is used to obtain the dry density ρ of the soil layer at each preset depth before compaction construction at the construction site. di ;

[0042] The test ramming result acquisition module is used to obtain the measured result L of the effective reinforcement depth of strong ramming after the test ramming. s And the dry density of the soil layer at each preset depth after the test tamping ρ sdi ;

[0043] Average dry density calculation module, used for the measured results of the effective reinforcement depth of strong compaction after test compaction L s , according to the dry density ρ of the soil layer at each preset depth before the strong compaction construction of the construction site di and the dry density ρ of the soil layer at each preset depth after the test tamping sdi , determine the average dry density ρ of the soil layer before dynamic compaction construction d1 and the average dry density of the soil layer after tamping ρ d2 ;

[0044] The tamping settlement calculation module is used to obtain the tamping settlement d after the formal dynamic tamping construction;

[0045] The dynamic compaction effective reinforcement depth calculation module is used to calculate the average dry density ρ of the soil layer before the dynamic compaction construction. d1 , the average dry density of the rammed soil layer ρ d2 The effective reinforcement depth of the construction site by dynamic compaction is calculated based on the amount of compaction settlement d after the formal dynamic compaction construction.

[0046] Compared with the prior art, the present invention has the following beneficial effects:

[0047] The present invention provides a method and system for calculating the effective reinforcement depth of strong tamping. The effective reinforcement depth of strong tamping is directly settled according to the average dry density of the soil layer before strong tamping construction, the average dry density of the soil layer after tamping and the tamping settlement amount after formal strong tamping construction. The calculation process is simple, and the randomness and deviation of the calculation result of the effective reinforcement depth of strong tamping are reduced. Specifically, compared with the original empirical formula method, the dependence on the correction coefficient can be reduced, and the deviation caused by the correction coefficient can be reduced. Directly using the average dry density and tamping settlement amount of the soil layer as calculation indicators is helpful to more accurately monitor and control the quality of the project. Since the changes in the average dry density and tamping settlement amount of the soil layer are directly and closely related to the tamping changes, the reinforcement effect can be better evaluated, and it has better predictability than pure theoretical analysis. Secondly, the tamping settlement amount measured on site is easy to obtain, and combined with the measurement of dry density, it is more direct and quick than pure theoretical calculation, which provides convenience for on-site adjustment and tracking management, simplifies the foundation construction process, and minimizes the dependence on the professional knowledge and experience of on-site engineers, and improves the ability to make immediate adjustments during the construction process. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 It is a flow chart of the method for calculating the effective reinforcement depth of dynamic compaction according to the present invention;

[0049] Figure 2 It is a schematic diagram of a calculation model of the method for calculating the effective reinforcement depth of dynamic compaction according to the present invention;

[0050] Figure 3It is a soil dry density variation curve diagram before and after the test tamping of the No. 1-3 points of a certain project in the present invention;

[0051] Figure 4 It is a curve diagram of the calculation results of the effective reinforcement depth of strong tamping after tamping test at different points of a certain project in the present invention;

[0052] Figure 5 The figure is a curve diagram showing the calculation results of the effective reinforcement depth of strong tamping at different points of a certain project by the present invention and the existing method. DETAILED DESCRIPTION

[0053] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention more clearly understood, the present invention is further described in detail in the following specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0054] As attached Figure 1 As shown, the present invention provides a method for calculating the effective reinforcement depth of dynamic tamping, comprising the following steps:

[0055] Step 1: Obtain the dry density ρ of the soil layer at each preset depth before the construction site compaction di Specifically, in the process of compiling the geological survey data of the construction site before the strong compaction construction of the construction site, the dry density data of each preset depth of the soil layer at the construction site is recorded from the geological survey data of the construction site, that is, the dry density ρ of each preset depth of the soil layer at the construction site before the strong compaction construction of the construction site is obtained. di Preferably, the dry density of the soil layer at each preset depth before the construction site is compacted is di It is the dry density of the soil layer at every 1m depth before the compaction construction at the construction site.

[0056] Step 2: Obtain the ground elevation of the construction site before compaction construction.

[0057] Step 3: Test tamping on the construction site to obtain the measured result of the effective reinforcement depth of strong tamping after the test tamping. s And the dry density of the soil layer at each preset depth after the test tamping ρ sdi ; Which specifically includes the following steps:

[0058] Determine the compaction construction plan based on the foundation bearing capacity requirements of the construction site and the on-site geological conditions.

[0059] According to the predetermined construction plan, test tamping is carried out in the corners of the construction site. After the test tamping is completed, undisturbed soil samples of a preset depth at each interval are obtained by drilling sampling or exploratory well excavation; preferably, the undisturbed soil samples of a preset depth at each interval are undisturbed soil samples at a depth of 1m at each interval.

[0060] According to the original soil samples at each preset depth, the measured results of the effective reinforcement depth after the test tamping are obtained. s And the dry density of the soil layer at each preset depth after the test tamping ρ sdi ; Preferably, the dry density of the soil layer at each preset depth after the test tamping is the dry density of the soil layer at each 1m depth after the test tamping.

[0061] Step 4: Based on the measured results of the effective reinforcement depth of the strong tamping after the test tamping, L s , according to the dry density ρ of the soil layer at each preset depth before the strong compaction construction of the construction site di and the dry density ρ of the soil layer at each preset depth after the test tamping sdi , determine the average dry density ρ of the soil layer before dynamic compaction construction d1 and the average dry density of the soil layer after tamping ρ d2 .

[0062] Specifically, the following steps are included:

[0063] According to the dry density ρ of the soil layer at each preset depth before the strong compaction construction of the construction site di And the dry density ρ of the soil layer at each preset depth after the test tamping sdi , and obtain the calculation results of the effective reinforcement depth of strong compaction after several tamping tests L si Among them, the calculation formula of the effective reinforcement depth of strong tamping after trial tamping is used to calculate the calculation results of the effective reinforcement depth of strong tamping after several trial tamping tests. si Calculation is performed; wherein the calculation formula for the effective reinforcement depth of the strong tamping after the test tamping is as follows:

[0064]

[0065] Among them, L si is the calculation result of the effective reinforcement depth of strong compaction after trial compaction; d i is the tamping amount after the test; ρ di ρ is the dry density of the soil layer at each preset depth before the construction site is compacted; sdi It is the dry density of soil layer at each preset depth after test compaction.

[0066] The calculation results of the effective reinforcement depth of the strong tamping after several test tamping are L si The measured result of the effective reinforcement depth after the test tamping is L s By comparison, the measured result L of the effective reinforcement depth after the test tamping is determined. s The calculation result of the effective reinforcement depth of the closest test tamping is used to obtain the depth L of the average dry density of the soil layer. q .

[0067] It should be noted that when determining the average dry density of the soil layer, the depth L q In the process of compaction, the dry density of the soil layer at each preset depth before the construction site is compacted is ρ di And the dry density ρ of the soil layer at each preset depth after the test tamping sdi Substitute into the calculation formula of the effective reinforcement depth of strong tamping after the test tamping, and obtain the calculation results of the effective reinforcement depth of strong tamping after the test tamping corresponding to the soil layers of different depths, that is, obtain the calculation results of the effective reinforcement depth of strong tamping after the test tamping L si ; The calculation results of the effective reinforcement depth of the strong tamping after the test tamping L si The measured result of the effective reinforcement depth after the test tamping is L s If the calculated effective reinforcement depth after a certain test is compared with the measured effective reinforcement depth after the test, L s The calculation result of the effective reinforcement depth of the strong compaction after the test compaction is the depth L of the average dry density of the soil layer. q .

[0068] According to the soil layer average dry density value depth L q And the dry density ρ of the soil layer at each preset depth before the strong compaction construction of the construction site di , the average dry density of the soil layer before compaction construction is calculated d1 Specifically, the dry density of the soil layer at each preset depth before the tamping construction at the construction site is ρ di In the above example, the depth L of the soil layer average dry density is selected. q The dry density of soil layers at different depths before compaction construction between the ground and the ground; the depth L at which the average dry density of the soil layer is taken q The dry density of soil layers at different depths before compaction construction between the original ground and the ground is summed and the average value is taken, that is, the average dry density of the soil layer before compaction construction ρ d1 .

[0069] According to the soil layer average dry density value depth L q And the dry density ρ of the soil layer at each preset depth after the test tamping sdi , the average dry density of the soil layer after tamping is calculated d2 Specifically, the dry density of the soil layer at each preset depth after the test tamping ρ sdi In the above example, the depth L of the soil layer average dry density is selected. q The dry density of soil layers at different depths after the test tamping between the ground surface after the test tamping; the depth L at which the average dry density of the soil layer is taken q The dry density of soil layers at different depths after tamping is summed and the average value is taken, that is, the average dry density of the soil layer after tamping is obtained. d2.

[0070] Step 5, obtaining the tamping amount d after the formal dynamic compaction construction; specifically, obtaining the ground elevation after the formal dynamic compaction; calculating the tamping amount d after the formal dynamic compaction construction based on the ground elevation before the dynamic compaction construction of the construction site and the ground elevation after the formal dynamic compaction; wherein the tamping amount d after the formal dynamic compaction construction is the difference between the ground elevation before the dynamic compaction construction of the construction site and the ground elevation after the formal dynamic compaction.

[0071] Step 6: According to the average dry density ρ of the soil layer before the dynamic compaction construction d1 , the average dry density of the rammed soil layer ρ d2 The calculation result of the effective reinforcement depth of the construction site by the tamping amount d after the formal tamping construction is calculated; wherein the calculation process of the calculation result of the effective reinforcement depth of the construction site by the tamping is as follows:

[0072]

[0073] Wherein, L1 is the calculation result of the effective reinforcement depth of the construction site by dynamic compaction, d is the tamping amount after the formal dynamic compaction construction; ρ d1 is the average dry density of the soil layer before dynamic compaction construction; ρ d2 is the average dry density of the soil layer after tamping.

[0074] The calculation result of the effective reinforcement depth of the construction site is calculated based on the average dry density of the soil layer before the dynamic compaction construction, the average dry density of the soil layer after the dynamic compaction construction, and the tamping settlement after the formal dynamic compaction construction.

[0075] Step 7: Compacting quality check

[0076] After the formal dynamic compaction construction is completed at the construction site, the site after the dynamic compaction construction is sampled and tested, and the dry density sampling test value at the sampling point is obtained; the dry density regional test value at the sampling point is compared with the dry density standard value ρ d3 The comparison is performed, and the dynamic compaction quality inspection result at the sampling point is determined according to the comparison result; wherein, when the dry density area detection value at the sampling point is less than the dry density standard value ρ d3 , the quality inspection result of the dynamic compaction at the sampling point is unqualified; otherwise, the quality inspection result of the dynamic compaction at the sampling point is qualified.

[0077] It should be noted that the dry density standard value ρ d3 The following conditions are met:

[0078] ρ d3 =ρ d ×λ c

[0079] ρd3 ×L3≤ρ d1 ×(L3+d)

[0080] Among them, ρ d3 is the dry density standard value; L3 is the sampling test depth after dynamic compaction construction; ρ d is the maximum dry density of the soil layer at the construction site determined by indoor geotechnical experiments; ρ d1 is the average dry density of the soil layer before dynamic compaction construction, λ c is the dry density reduction factor.

[0081] Compared with the original empirical formula method, the method and system for calculating the effective reinforcement depth of strong compaction described in the present invention can reduce the dependence on the correction coefficient and reduce the deviation caused by the correction coefficient; directly using the average dry density and tamping amount of the soil layer as calculation indicators is helpful to more accurately monitor and control the quality of the project. Since the changes in the average dry density and tamping amount of the soil layer are directly and closely related to the compaction changes, the reinforcement effect can be better evaluated, and it has better predictability than pure theoretical analysis; secondly, the actual tamping amount measured on site is easy to obtain, and the measurement combined with the dry density is more direct and faster than pure theoretical calculation, which facilitates on-site adjustment and tracking management, simplifies the foundation construction process, and minimizes the dependence on the professional knowledge and experience of on-site engineers, and improves the ability to make immediate adjustments during the construction process.

[0082] Calculation principle:

[0083] When using the dynamic compaction method for foundation treatment, the effective reinforcement depth of dynamic compaction not only depends on the single-shot compaction energy, but is also closely related to other factors; among them, the single-shot compaction energy is the product of the hammer weight and the drop distance; but before and after the dynamic compaction construction, the dynamic compaction only changes the properties of the soil, while the total amount of soil in the construction site remains unchanged; secondly, the deformation of the soil layer before and after the dynamic compaction construction of the construction site changes in the one-dimensional vertical direction, and no horizontal diffusion occurs; in addition, the volume of soil particles in the construction site remains unchanged before and after the dynamic compaction construction.

[0084] Since the dry density of the soil layer changes continuously from top to bottom before and after strong compaction, the dropped hammer compacts the soil layer during strong compaction, and the energy decays with the depth of the soil layer. There is often a strong dense layer after strong compaction; among them, the dry density below the strong dense layer often varies greatly, and the stratum often shows that the dry density of the upper stratum is extremely large, and the dry density decreases rapidly with increasing depth.

[0085] As attached Figure 2 As shown in the figure, assuming that the effective reinforcement depth of a construction site is L1, that is, the distance between the original ground and the strong compacted layer is L1; and the distance between the ground and the strong compacted layer after compaction is L2; ​​at this time, the average dry density of the soil layer before and after the compaction construction satisfies the following formula (1):

[0086] ρ d1 ×L1=ρ d2 ×L2 (1)

[0087] Where: d1 is the average dry density of the soil layer before dynamic compaction construction; ρ d2 is the average dry density of the soil layer after tamping.

[0088] Secondly, the tamping amount d after the strong tamping construction is the difference between the distance L1 between the original ground and the strong dense layer and the distance L2 between the ground and the strong dense layer after tamping, that is:

[0089]

[0090] Among them, d is the amount of compaction after dynamic compaction construction.

[0091] Therefore, the effective reinforcement depth L1 of dynamic compaction is:

[0092]

[0093] Among them, L1 is the effective reinforcement depth of dynamic compaction.

[0094] It should be noted that the value of the tamping settlement d after the dynamic compaction construction is the difference between the original ground elevation before the dynamic compaction construction and the ground elevation after the formal dynamic compaction; and the average dry density of the soil layer before the dynamic compaction construction ρ d1 And the average dry density of the soil layer after tamping ρ d2 By being able to calculate the dry density of the soil layer at each preset depth before the construction site compaction di And the dry density of the soil layer at each preset depth after the test tamping ρ sdi The dry density of the soil layer at each preset depth before the construction site compaction is calculated as follows: di And the dry density of the soil layer at each preset depth after the test tamping ρ sdi It can be tested through existing experimental conditions on site; the dry density of the soil layer is the ratio of the mass of solid particles to the total volume of the soil.

[0095] When using the above formula (3) to calculate the effective reinforcement depth of dynamic compaction, the average dry density of the soil layer before dynamic compaction construction within the appropriate depth is selected as d1 The average dry density of the soil layer after tamping ρ d2It is the key to ensure the accuracy of the calculation results, that is, the depth of the average dry density of the soil layer can directly affect the calculation result of the effective reinforcement depth of strong compaction; therefore, after the strong compaction plan is confirmed, the construction site conducts a trial compaction in a preset corner before carrying out large-scale strong compaction. After the trial compaction, the actual effective reinforcement depth is comprehensively judged by the measured values ​​of the static penetration test and the standard penetration test, that is, the measured result of the effective reinforcement depth of strong compaction after the trial compaction is obtained; then, according to the on-site dry density test results, the average dry density of each preset depth of the stratum after compaction is taken and substituted into the calculation formula of the effective reinforcement depth of strong compaction after the trial compaction, and the calculated result is compared with the measured result of the effective reinforcement depth of strong compaction after the trial compaction, among which the depth that the calculated result is consistent with or closest to the actual effective reinforcement depth is the average dry density ρ of the soil layer before strong compaction construction at this energy level. d1 The average dry density of the soil layer after tamping ρ d2 The recommended depth.

[0096] If necessary, the average dry density of the soil layer before compaction construction is d1 The average dry density of the soil layer after tamping ρ d2 are the average dry density of the soil layer, which has a limit. Due to the complex construction conditions of the site, it is impossible to perform strong compaction at the optimum moisture content of the soil. Therefore, the dry density of the stratum after strong compaction is difficult to reach the maximum dry density ρ obtained by indoor geotechnical experiments. d ; Therefore, the maximum dry density on site needs to be multiplied by the reduction factor λ c , the maximum dry density on site is ρ ds .

[0097] After the on-site dynamic compaction, the construction quality of the dynamic compaction needs to be inspected, and the dry density is an important indicator for judging the construction quality. The following formulas (4) and (5) can calculate the appropriate dry density evaluation standard. After determining the limited reinforcement depth of dynamic compaction required by the design, the inspection unit will take points for inspection at the dynamic compaction site. When the number of inspection points that do not meet the reinforcement requirements accounts for a large proportion, it is necessary to take measures such as excavation, filling and layered compaction of the site. Among them, the on-site dry density inspection limit is crucial to evaluating whether the dynamic compaction effect is qualified. If the inspection dry density meets the standard value of ρ d3 , the depth to be tested after tamping is L3; then the dry density standard value ρ d3 The following formula should be satisfied:

[0098] ρ d3 =ρ d ×λ c (4)

[0099] ρ d3 ×L3≤ρ d1 ×(L3+d) (5)

[0100] When the test data does not satisfy formula (5), the λ in formula (4) should be appropriately reduced. c In order to obtain appropriate dry density detection limit after on-site compaction, it can better guide on-site construction and establish reasonable dry density inspection requirements for compaction site quality.

[0101] Project example description:

[0102] By using the calculation method of the effective reinforcement depth of the dynamic tamping described in the present invention, when a certain construction site is treated by the dynamic tamping method using the 6000kN energy level; as shown in the attached Figure 3 As shown, attached Figure 3 The dry density variation curve of soil at points 1-3 of a certain project before and after the tamping test is given in the attached Figure 3 It can be seen that the maximum dry density of the soil layer at the construction site is 1.4-1.7g / cm 3 ; as attached Figure 4 As shown, attached Figure 4 The curve diagram of the calculation results of the effective reinforcement depth of strong compaction after test compaction at different points of a certain project is given in the Appendix. Figure 4 It can be seen from the figure that the calculated result of the effective reinforcement depth of strong compaction obtained when the depth of the average dry density of the soil layer is 5.4m is different from the measured result of the effective reinforcement depth of strong compaction after the test compaction; as shown in the attached figure Figure 5 As shown, attached Figure 5 The calculation results of the effective reinforcement depth of the present invention and the existing method for a certain project at different points are given in the figure; Figure 5 It can be seen that when the 6000kN energy level is used for strong compaction, compared with the calculation in the specification and Menard's empirical formula, the effective reinforcement depth of strong compaction calculated by the method of the present invention is closest to the measured value.

[0103] The present invention also provides a system for calculating the effective reinforcement depth of strong compaction, including a module for obtaining dry density before compaction, a module for obtaining test compaction results, a module for calculating average dry density, a module for calculating compaction settlement, and a module for calculating the effective reinforcement depth of strong compaction; wherein the module for obtaining dry density before compaction is used to obtain the dry density ρ of each preset depth of soil layer before the strong compaction construction of the construction site. di The test ramming result acquisition module is used to obtain the measured result L of the effective reinforcement depth of the strong ramming after the test ramming. s And the dry density of the soil layer at each preset depth after the test tamping ρ sdi The average dry density calculation module is used to calculate the measured results of the effective reinforcement depth of the strong tamping after the test tamping. s , according to the dry density ρ of the soil layer at each preset depth before the strong compaction construction of the construction site di and the dry density ρ of the soil layer at each preset depth after the test tamping sdi , determine the average dry density ρ of the soil layer before dynamic compaction construction d1and the average dry density of the soil layer after tamping ρ d2 The tamping amount calculation module is used to obtain the tamping amount d after the formal dynamic tamping construction; the dynamic tamping effective reinforcement depth calculation module is used to calculate the average dry density ρ of the soil layer before the dynamic tamping construction d1 , the average dry density of the rammed soil layer ρ d2 The effective reinforcement depth of the construction site by dynamic compaction is calculated based on the amount of compaction settlement d after the formal dynamic compaction construction.

[0104] The method and system for calculating the effective reinforcement depth of strong tamping described in the present invention use the measured tamping amount and the average dry density of the soil layer to calculate the effective reinforcement depth of strong tamping; compared with the original empirical formula method, the dependence on the correction coefficient can be reduced, and the economic loss caused by the correction coefficient can be reduced; the calculation process is simple and the calculation accuracy is high, which is suitable for the method of calculating the effective reinforcement depth of strong tamping based on the detection data at the construction site; since the correction coefficient in the existing empirical formula has a large uncertainty, the deviation of the result may require more expensive engineering adjustment costs, and even lead to over-design, and increase material and construction costs; and using the measured data to accurately estimate the design depth can make more economical and efficient use of resources and reduce the overall engineering cost.

[0105] In the present invention, the reliance on empirical correction coefficients is reduced, and the engineering effect is evaluated by directly observing the state of the soil after reinforcement, so that the stability state of the reinforced area can be more accurately reflected; at the same time, insufficient evaluation due to inaccurate correction coefficients is avoided, and a more intuitive and reliable indicator is provided in verifying engineering safety, which helps to ensure the robustness of the structure and long-term operational safety, and effectively avoid the increase in later maintenance costs due to insufficient reinforcement.

[0106] In the present invention, the average dry density and tamping amount of the soil layer are directly used as calculation indicators, which is helpful to more accurately monitor and control the quality of the project. Since the changes in the average dry density and tamping amount of the soil layer are directly and closely related to the compaction changes, the reinforcement effect can be better evaluated, and it has better predictability than pure theoretical analysis; secondly, the stability and bearing capacity of the soil layer after strong tamping are ensured through performance improvement, thereby ensuring the normal use of the structure and extending its service life; in addition, the tamping amount measured on site is easy to obtain, and the measurement combined with the dry density is more direct and faster than pure theoretical calculation, and the field measurement data can be imported into a pre-compiled calculation tool, such as an Excel table, to quickly obtain the results; it provides convenience for on-site adjustment and tracking management, simplifies the construction process, and minimizes the dependence on the expertise and experience of on-site engineers, and improves the ability to make immediate adjustments during the construction process.

[0107] The above embodiment is only one of the implementation methods that can realize the technical solution of the present invention. The scope of protection claimed by the present invention is not limited only to this embodiment, but also includes changes, replacements and other implementation methods that can be easily thought of by any technician familiar with the technical field within the technical scope disclosed by the present invention.

Claims

1. A method for calculating the effective reinforcement depth of dynamic tamping, characterized in that: include: Get the dry density ρ of the soil layer at each preset depth before the construction site compaction di ; Obtain the measured result L of the effective reinforcement depth of strong compaction after the test compaction s And the dry density of the soil layer at each preset depth after the test tamping ρ sdi ; Based on the measured results of the effective reinforcement depth of strong compaction after the test compaction, L s , according to the dry density ρ of the soil layer at each preset depth before the strong compaction construction of the construction site di and the dry density ρ of the soil layer at each preset depth after the test tamping sdi , determine the average dry density of the soil layer before compaction construction ρd1 and the average dry density of the soil layer after tamping ρ d2 ; Obtain the tamping settlement amount d after the formal dynamic tamping construction; According to the average dry density of the soil layer before the dynamic compaction construction, ρ d1 , the average dry density of the rammed soil layer ρ d2 The effective reinforcement depth of the construction site by dynamic compaction is calculated based on the amount of compaction settlement d after the formal dynamic compaction construction.

2. The method for calculating the effective reinforcement depth of dynamic tamping according to claim 1 is characterized in that: Get the dry density ρ of the soil layer at each preset depth before the construction site compaction di The process is as follows: From the geological survey data of the construction site, record the dry density data of each preset depth of the soil layer at the construction site, that is, the dry density ρ of each preset depth of the soil layer at the construction site before the strong compaction construction is obtained. di .

3. The method for calculating the effective reinforcement depth of dynamic tamping according to claim 1 is characterized in that: Obtain the measured result L of the effective reinforcement depth of strong compaction after the test compaction s And the dry density of the soil layer at each preset depth after the test tamping ρ sdi The process is as follows: According to the predetermined dynamic compaction construction plan, test compaction is carried out in the corners of the construction site. After the test compaction, the original soil samples of each preset depth are obtained by drilling or excavating a well. Based on the original soil samples of each preset depth, the actual measured results of the effective reinforcement depth of dynamic compaction after the test compaction are obtained. s And the dry density of the soil layer at each preset depth after the test tamping ρ sdi .

4. The method for calculating the effective reinforcement depth of dynamic tamping according to claim 1 is characterized in that: Based on the measured results of the effective reinforcement depth of strong compaction after the test compaction, L s , according to the dry density ρ of the soil layer at each preset depth before the strong compaction construction of the construction site di and the dry density ρ of the soil layer at each preset depth after the test tamping sdi , determine the average dry density ρ of the soil layer before dynamic compaction construction d1 and the average dry density of the soil layer after tamping ρ d2 The process is as follows: According to the dry density ρ of the soil layer at each preset depth before the strong compaction construction of the construction site di And the dry density ρ of the soil layer at each preset depth after the test tamping sdi , and obtain the calculation results of the effective reinforcement depth of strong compaction after several tamping tests L si ; The calculation results of the effective reinforcement depth of the strong tamping after several test tamping are L si The measured result of the effective reinforcement depth after the test tamping is L s By comparison, the measured result L of the effective reinforcement depth after the test tamping is determined. s The calculation result of the effective reinforcement depth of the closest test tamping is used to obtain the depth L of the average dry density of the soil layer. q ; According to the soil layer average dry density value depth L q And the dry density ρ of the soil layer at each preset depth before the strong compaction construction of the construction site di , the average dry density of the soil layer before compaction construction is calculated d1 ; According to the soil layer average dry density value depth L q And the dry density ρ of the soil layer at each preset depth after the test tamping sdi , the average dry density of the soil layer after tamping is calculated d2 .

5. A method for calculating effective reinforcement depth by dynamic tamping according to claim 4, characterized in that: Calculation results of effective reinforcement depth L after several tamping tests si The calculation process is as follows: Among them, L si is the calculation result of the effective reinforcement depth of strong compaction after trial compaction; d i is the tamping amount after the test; ρ di ρ is the dry density of the soil layer at each preset depth before the construction site is compacted; sdi It is the dry density of soil layer at each preset depth after test compaction.

6. A method for calculating effective reinforcement depth by dynamic tamping according to claim 4, characterized in that: According to the soil layer average dry density value depth L q And the dry density ρ of the soil layer at each preset depth before the strong compaction construction of the construction site di , the average dry density of the soil layer before compaction construction is calculated d1 The process is as follows: The dry density ρ of the soil layer at each preset depth before the strong compaction construction at the construction site di In the above example, the depth L of the soil layer average dry density is selected. q Dry density of soil layers at different depths before compaction to the original ground; The depth L of the soil layer average dry density q The dry density of soil layers at different depths before compaction construction between the ground and the ground is summed and the average value is taken, that is, the average dry density of the soil layer before compaction construction ρ d1 .

7. A method for calculating effective reinforcement depth by dynamic tamping according to claim 4, characterized in that: According to the soil layer average dry density value depth L q And the dry density ρ of the soil layer at each preset depth after the test tamping sdi , the average dry density of the soil layer after tamping is calculated d2 The process is as follows: The dry density ρ of the soil layer at each preset depth after the test tamping sdi In the above example, the depth L of the soil layer average dry density is selected. q Dry density of soil layers at different depths after tamping test to the ground after tamping test; The depth L of the soil layer average dry density q The dry density of soil layers at different depths after tamping is summed and the average value is taken, that is, the average dry density of the soil layer after tamping is obtained. d2 .

8. The method for calculating the effective reinforcement depth of dynamic tamping according to claim 1 is characterized in that: The process of obtaining the tamping settlement d after the formal dynamic tamping construction is as follows: Obtain the ground elevation of the construction site before and after the compaction; According to the ground elevation before the dynamic compaction construction and the ground elevation after the formal dynamic compaction construction of the construction site, the tamping amount d after the formal dynamic compaction construction is calculated.

9. The method for calculating the effective reinforcement depth of dynamic tamping according to claim 1, characterized in that: The calculation process of the calculation result of the effective reinforcement depth of the construction site is as follows: Wherein, L1 is the calculation result of the effective reinforcement depth of the construction site by dynamic compaction, d is the tamping amount after the formal dynamic compaction construction; ρ d1 is the average dry density of the soil layer before dynamic compaction construction; ρ d2 is the average dry density of the soil layer after tamping.

10. A system for calculating the effective reinforcement depth of dynamic tamping, characterized in that: include: The module for obtaining dry density before compaction is used to obtain the dry density ρ of the soil layer at each preset depth before compaction construction at the construction site. di ; The test ramming result acquisition module is used to obtain the measured result L of the effective reinforcement depth of strong ramming after the test ramming. s And the dry density of the soil layer at each preset depth after the test tamping ρ sdi ; Average dry density calculation module, used for the measured results of the effective reinforcement depth of strong compaction after test compaction L s , according to the dry density ρ of the soil layer at each preset depth before the strong compaction construction of the construction site di and the dry density ρ of the soil layer at each preset depth after the test tamping sdi , determine the average dry density ρ of the soil layer before dynamic compaction construction d1 and the average dry density of the soil layer after tamping ρ d2 ; The tamping settlement calculation module is used to obtain the tamping settlement d after the formal dynamic tamping construction; The dynamic compaction effective reinforcement depth calculation module is used to calculate the average dry density ρ of the soil layer before the dynamic compaction construction. d1 , the average dry density of the rammed soil layer ρ d2 The effective reinforcement depth of the construction site by dynamic compaction is calculated based on the amount of compaction settlement d after the formal dynamic compaction construction.

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