54 results about "Limit equilibrium method" patented technology

The invention relates to a method of detecting stability of a rock mass side slope and warning and forecasting instability of the side slope by adopting motive power increment displacement response ratio parameters. A motive power monitoring and warning method of rock mass landslide includes the following steps: (1) ensuring side slope geometric elements to be detected, mapping of a sliding surface and self weight of a landslide body, (2) designing and arranging side slope downward sliding motive power and displacement monitoring points, (3) monitoring and ensuring the side slope downward sliding motive power and downward sliding displacement response, (4) ensuring side slope downward sliding motive power loading rate parameters, (5) ensuring side slope downward sliding displacement response rate parameters, (6) ensuring landslide motive power increment displacement response rate parameters, (7) ensuring a landslide stability motive power increment displacement response rate criterion, and (8) monitoring side slope stability and monitoring and early warning. Stability coefficients of a limit equilibrium method are organically coupled with a displacement timing sequence analytic method and characteristics of displacement predictive parameters, and limitations of a traditional method are overcome.

The invention relates to a quantitative evaluation method for dynamic stability of a creep-type side slope, in particular to a method for determining a dynamic stability coefficient of the creep-type side slope. The method includes the following steps: (1), measuring related parameters of the side slope and determining an initial stability coefficient F0; (2), arranging side slope displacement monitoring points and acquiring displacement monitoring data; (3), determining side slope creep rupture instability time and a stability coefficient Ft in a constant-speed creep stage; (4), determining an initial point tc and a stability coefficient Ftc in a side slope accelerated creep stage; (5), determining the dynamic stability coefficient in an accelerated deformation stage of the creep-type side slope; (6), determining a criterion for early warning of instability of the creep-type side slope. By the method, instability time of the creep-type side slope and landslide safety coefficients of the side slope at any time can be determined clearly, the limitation of incapability of analyzing and evaluating the dynamic stability of the side slop in real time according to conventional balance methods is overcome, and efficiency of dynamic stability evaluation and monitoring and early warning of the complex creep-type side slope can be greatly improved.

The invention relates to a method for dike side slope two-dimensional safety and stability analysis taking shield pass-through influences into consideration. The method for dike side slope two-dimensional safety and stability analysis includes the steps that based on the stress dispersion principle, a stress dispersion angle of shield thrust in a dike foundation is acquired, the range of influence, namely the reinforcement range of shield construction is determined according to the reinforcement position of an excavation face which is most unfavorable to dike safety and stability, the range of influence is divided into a plurality of stripes in the longitudinal direction of a dike, and each stripe is divided into a plurality of soil stripes; based on the Mindlin principle, through numerical integration, additional gliding thrust transmitted by shield extrusion on the slip circle position of each soil stripe on each stripe is acquired, and the additional gliding thrust is applied to one certain stripe through arithmetic averaging; finally, according to a two-dimensional plane limit equilibrium method, dike side slope safety and stability coefficients can be calculated and analyzed, comparison is conducted according to relevant design standards and initial dike safety and stability, and therefore the influences of shield construction on dike safety and stability can be scientifically, quantitatively and reasonably evaluated.

The invention discloses a measuring method of a double slip surface rock mass slope anchorage optimization parameter. The method comprises the steps of firstly determining spatial geometric elements and physical and mechanical properties of a slope through scene investigation, adopting a stereographic projection method to determine the unstable rock mass structure slope and a normal inclined angle between an anchor rod and a structural surface intersecting line of the slope, obtaining the IO inclined angle between the slope optimal anchor rod and the structural surface intersecting line by conducting derivation on a slope stability coefficient, and correspondingly determining optimal anchorage force and an anchorage force correction coefficient on the condition of common construction. According to the measuring method of the double slip surface rock mass slope anchorage optimization parameter, on the basis of stereographic polar projection, a limit equilibrium method is adopted to analyze a slip law of a wedge-shaped body, and an anchor bolt support method applicable for the wedge-shaped double slip surface rock mass slope is explored; thereby, the stability of the rock mass slope under the influence of various slip tendencies is strengthened, and the effectiveness and practicability of the method are shown.

The invention relates to a rain-induced landslide critical start-up rainfall and instability early-warning time determination method, which comprises the following steps: Step 1, determination of physical and mechanical property parameters of a slope and slope angle and slope vertical depth; Step 2, monitoring of landslide slope rainfall and monitoring data processing; Step 3, determination of landslide start-up groundwater level critical depth value; Step 4, determination of landslide start-up effective rainfall threshold; Step 5, determination of real-time critical start-up rainfall of the slope; Step 6, slope stability analysis and evaluation; and Step 7, determination of slope instability early-warning time. The invention creatively puts forward a landslide stability real-time start-up rainfall determination and slope stability evaluation method based on a limit equilibrium method and with the combination of real-time rainfall monitoring. By real-time monitoring of rainfall, slope critical start-up rainfall can be detected and determined. The method has important application prospect and value in landslide hazard monitoring early-warning and stability evaluation.

The invention relates to a slope stability limit balance calculation method based on the inter-strip normal force distribution characteristics, and belongs to the technical field of slope stability. An inter-strip normal force distribution form is not considered when the slope stability is analyzed by a traditional limit balance strip division method, namely, the influence of different thrust lineacting positions on the safety coefficient is realized, based on an existing limit balance bar division method, the inter-strip normal force distribution characteristics are further considered, namely, the distribution of thrust line acting positions is realized, an improved limit balance calculation method considering inter-strip normal force distribution characteristics is provided, the resultof calculating the deep concave sliding surface by using the improved limit balance Spender method provided by the invention is discovered, an improved limit balance method and a traditional limit balance method have large safety coefficient errors, the error value reaches about 20%, the method has the advantages of being simple, convenient and reliable, a more accurate result is provided for slope stability analysis, the engineering safety can be improved, the construction cost can be reduced, and the engineering economic benefit can be improved.

The invention relates to a numerical simulation and limit equilibrium calculation-based landslide hazard assessment method. The assessment method comprises the steps of building a corresponding numerical model by adopting a large deformation numerical simulation method in combination with field survey data and related modeling methods, and determining landslide body form contour lines and key position coordinates of different positions in a landslide path; based on a ring shear or direct shear test, determining residual shear strength of a landslide body-slope surface boundary plane; analyzingand calculating landslide body factors-of-safety of different positions and landslide body forms in the landslide path by utilizing a limit equilibrium method, namely, performing FOS calculation; determining FOS specifications of specification requirements, wherein indexes needed to be considered for determination of the specific FOS include a sliding distance, a landslide speed, the number of people in a hazard range, and a land resource type of a hazard-bearing body; and establishing a landslide hazard degree calculation formula and determining landslide hazard level judgment standards. Themethod is suitable for hazard assessment of all types of soil landslides, and has good application prospects.

The invention belongs to the field of slope stability and risk evaluation, and particularly relates to a slope risk comprehensive evaluation method based on a landslide failure form, which comprises the following steps: randomly generating n groups of combined values conforming to statistical characteristics according to the statistical characteristics of cohesive force c and an internal frictionangle, and recording the n groups of combined values as the ith group of combined values to obtain the minimum safety factor Fsi of a slope; analyzing the slip-off distance dRi and the influence distance dIi of the slope under the ith group of combined values by using a smoothed particle hydrodynamics method; making i= i + 1, repeating the previous two steps, and obtaining the minimum safety coefficient, the sliding-out distance and the influence distance of the slope under all the combined values; averaging to obtain an average safety coefficient, slip-off and influence distance; and calculating a normalized slide-out distance and an influence distance according to the positions of the slope crest and slope bottom structures, and comprehensively evaluating the landslide risk together withthe average safety coefficient. The smooth particle hydrodynamic method is introduced, and the slope stability and risk are evaluated more visually and reasonably by using the slip-off distance and the influence distance and combining the classical limit equilibrium method.

The invention discloses a landslide interval stability analysis method based on a particle swarm optimization algorithm, and the method comprises the following steps: (1), determining an uncertainty variable and an interval thereof in stability analysis according to the landslide engineering condition, and enabling the uncertainty variable and the interval thereof to serve as a search variable anda search space of the particle swarm optimization algorithm; (2) setting particle swarm optimization algorithm parameters, and determining an interval limit balance safety coefficient function as a fitness function according to a landslide limit balance method and an uncertainty variable; (3) initializing the speed and the position of each particle, calculating the adaptive value of each particle, determining an individual, a global minimum/maximum safety factor and the corresponding individual, and updating the particle position; and (4) iterating until a set iteration frequency is reached and the global minimum/maximum safety coefficient is not obviously improved, wherein the global minimum/maximum safety coefficient is the lower limit value/upper limit value of the landslide safety coefficient calculation interval. According to the method, an accurate safety coefficient interval can be obtained, and the interval expansion problem is effectively avoided.

The invention belongs to the technical field of geotechnical engineering, and particularly relates to a concrete pile composite foundation stability calculation method. The method comprises the steps:A, determining the roadbed structure size, and determining physical parameters of the roadbed and the reinforcing material; B, determining the position and parameters of an initial sliding surface ofthe foundation; C, determining the ultimate bending moment of the concrete pile considering the cushion layer tie bar effect; D, determining the equivalent shearing resistance of the concrete pile; E, analyzing the stability of the reinforced foundation by adopting an extreme balance method. According to the method, the constraint effect of the cushion layer tie bars on pile body deformation in the composite foundation is considered, the contribution of the cushion layer tie bars under the embankment to the anti-sliding capacity of the pile bodies in the composite foundation can be reflectedmore accurately, and good practicability and reliability are achieved.

The invention belongs to the field of engineering slope and geological disaster evaluation, and relates to a measuring method of a slippage face. The slopes of all monitoring point total displacement vectors on one profile are used, a slippage face shape curve, namely the slippage face position under a certain coordinate is calculated through the least square method and the regression iterative, the slope displacement vector angle iteration is used for approaching a true slippage face in any shape, and the defects that existing engineering geology reconnaissance practical work is heavy, the limit equilibrium method trial process is complex and long, or human factor disturbance enables results to have one-sidedness and boundedness are overcome; selection of a constitutive relation and soil layer physical and mechanics parameters in finite element software is effectively avoided; and according to the method, displacement vector angle iteration is jointly achieved through programming language, the AUTO CAD mapping software and the Microsoft Excel data processing software, and the true slippage face position is determined. The measuring method is simple in process procedure, the slope sliding section position determination is accurate, calculation data are accurate, and application is wide.

The invention discloses a tailings reservoir saturation line on-line monitoring point layout and zigbee networking structure. A tailing dam stability monitoring analysis profile of vertical axis of dam is established; stability analysis of each dam profile is carried out under flood routing operating conditions by a limit equilibrium method, the dam profile with the minimum stability coefficient is selected as a main saturation line monitoring profile, and no fewer than 4 monitoring points are laid; other profiles are used as auxiliary monitoring profiles, and each profile has fewer than 2 monitoring points; through a saturation line acquisition instrument, teletransmission based on zigbee wireless networking as the core is established to complete acquisition, monitoring and transmission of field data; automatic query of partial nodes, display of database lists and display of graphic images are realized through management software of a central monitoring computer; and packet loss ratio is obtained through comparison between transmit data and receive data, and stability of the lay-out method is determined. The invention has characteristics of clear priority, emphasis on key points, few monitoring points, reliable transmission and analysis accuracy.

The invention provides a tunnel face grouting parameter design method and belongs to the field of tunnel engineering. According to the tunnel face grouting parameter design method, the damage mode of a tunnel face under a mechanized full-section working method is considered, a calculation formula for the cohesive force increasing coefficient alpha1 of surrounding rock in front of the tunnel face after grouting is derived through a volume equivalence method, and a calculation method for the stabilization coefficient of the tunnel face is derived through a limit equilibrium method, so that quantitative design of grouting parameters of the tunnel face of a tunnel is realized.

The invention provides a tunnel face anchor rod support design method, and belongs to the field of tunnel engineering. In the design method of the tunnel face anchor rod, a tunnel face damage mode under a mechanized full-section construction method is considered; meanwhile, five tensile failure modes of the GFRP anchor rod of the tunnel face and influences of reinforcing parameters such as the diameter of the anchor rod, the reinforcing density, the initial length, the lap joint length, the tensile strength of the anchor rod, the shear strength of an anchor rod-grouting body interface and the shear strength of a grouting body-surrounding rock interface are considered; and a tunnel face stability coefficient calculation formula is deduced by adopting an extreme balance method, and the GFRP anchor rod quantitative design of the tunnel face is achieved.

The invention relates to a construction project evaluation method, in particular to a slope excavation stability evaluation method. The method comprises the following steps of: acquiring initial dynamic elastic moduli of different depths of an underground high and steep slope before excavation and dynamic elastic moduli in an excavation process; calculating dynamic elastic modulus change values corresponding to different stratum depths, and determining the average damage degree of slope excavation; and establishing a quantitative relationship between the average damage degree and a stability coefficient, and determining the stability coefficient in the slope excavation process. According to the slope excavation stability evaluation method based on dynamic elastic modulus monitoring provided by the invention, the time factor can be considered, the dynamic cause and mechanism of slope instability are coupled, and the defects and limitation of application of a traditional limit equilibrium method and a displacement time sequence method can be effectively overcome.

The invention relates to a method for testing mechanical property of an uplift pile under a deep excavation condition. The method comprises the following steps: (1) building a vertical tension mechanical model of a base-enlarged uplift pile by utilizing a numerical value analysis method, a centrifugal model test, a limit equilibrium method and a limit analysis method; (2) acquiring failure mechanism and load bearing characteristics of a uniform-section uplift pile and the base-enlarged uplift pile, and uplift bearing capability loss characteristics of the piles under excavation unloading based on the centrifugal model test and numerical simulation; (3) proposing three calculation methods of bearing loss of the uplift pile under a predicted deep excavation condition; and (4) determining a critical failure surface by utilizing an improved Monte-Carlo search technique, building a multi-block upper limit analysis method for a limit bearing capability of a base-enlarged uplift pile to obtain data of the mechanical property of the uplift pile under the deep excavation condition. Compared with the prior art, the method for testing the mechanical property of the uplift pile under the deep excavation condition, disclosed by the invention, has the following advantages of optimizing design and construction schemes, saving engineering investment, improving an analysis theory of the uplift pile and the like.

The invention discloses a soil-rock combined slope stability analysis method based on a graphic trial algorithm. The method comprises the following steps: from a slope toe, obtaining a first minimum safety factor Fs1 by adopting an extreme balance method; secondly, searching the most unfavorable arc sliding surface of the supposed arc sliding surface of the upper soil body by adopting a slitting method, and calculating the residual gliding force; drawing the lower rock mass at the first worst inclination angle alpha to obtain a sliding structural surface, and taking the soil strip gravity andthe downward sliding force of the upper soil mass contained in the upper sliding structural surface as external loads to obtain a second minimum safety coefficient Fs2; from the slope toe, taking a rock-soil body, which is separated from the arc sliding surface of the soil body by the most unfavorable sliding surface of the upper soil body and the tangent plane of the lower rock body in a rock body, as an independent body to obtain a third minimum safety coefficient Fs3; and taking the minimum value as the final minimum safety factor Fsmin of the soil-rock combined slope. The invention conforms to the assumption of the traditional soil mechanics on the arc sliding surface of the soil body and the assumption of the traditional rock mechanics on the inclined sliding surface of the rock body.

The invention provides a method for analyzing the sliding stability of a wedge-shaped body of a rock slope based on a coordinate system conversion method, which comprises the following steps of: establishing a three-dimensional geological analysis model of the wedge-shaped body slope by considering various factors such as rock mass structure characteristic parameters and geometric characteristic parameters of a sliding mass and a sliding bed, anchor cable support parameters and the like; deducing a calculation formula of partial size parameters and spatial arrangement parameters of the model by a spatial geometric analysis method, and using a coordinate system conversion method, a tensor analysis method and the like to effectively decompose gravity G borne by a wedge-shaped slope sliding body and pre-tension T under anchor cable three-dimensional support to the normal direction of two groups of sliding surfaces and the sliding direction of the sliding body; calculating the sliding force F < down > and the sliding resistance F < resistance > borne by the wedge-shaped body slope before and after anchoring by a limit equilibrium method, completing a traditional solution formula of the stability coefficient of the wedge-shaped body slope before and after anchoring, so that the stability analysis precision of the wedge-shaped body slope is effectively improved.

The invention discloses a diversion tunnel straight pillar plug length design method. The method comprises the steps that (1) a rigid body limit equilibrium method is adopted to calculate the effective length L<0> of a conventional wedge-shaped plug; (2) a three-dimensional finite element method is adopted to perform calculation analysis on a straight pillar plug and the conventional wedge-shapedplug, and safety stock P<0>provided by a wedging effect is obtained; (3) safety stock P<m> provided by surrounding rock supporting anchor rods of the straight pillar plug and safety stock P<c> provided by plug downstream section linings are calculated respectively, and the sum P<1> which is equal to P<m>+P<c> is calculated; (4) P<1> and P<0> are compared; if P<1> is greater than or equal to P<0>,the effective length of the straight pillar plug is L<j> which is equal to L<0>; and if P<1> is smaller than P<0>, the difference is provided by increasing plug length delta(L), and L<j> is equal to L<0>+delta(L); and (5) the design length of the straight pillar plug is L<z> which is greater than or equal to L<j>. The method overcomes the defect that the water-retaining extra safety stock of an existing straight pillar plug is lowered compared with the conventional wedge-shaped plug, and the method is a supplement to an existing plug length design method and is beneficial for promoting application of the straight pillar plug in a diversion tunnel and particularly a large diversion tunnel plugging project.