CN105178336B - Method for determining ultimate bearing capacity of refuse dump with weak foundation base - Google Patents

Abstract

The invention discloses a method for determining the ultimate bearing capacity of a refuse dump with a weak foundation base. The method comprises the steps that firstly, the ultimate dump height H90 is calculated by means of a Prandtl foundation ultimate bearing capacity formula under the condition that a triangular load on the side face of the refuse dump is not considered; secondly, the functional relationship between the slip moment increment delta M and delta H and the functional relationship between the anti-slip moment delta M' generated by the triangular load on the side face and delta H are determined respectively according to the side slope angle beta, the slope height H90+delta H and the position of a slope line of the refuse dump; thirdly, a slip moment increment delta M-delta H curve and an anti-slip moment delta M'-delta H curve are drawn, and whether the two curves intersect with each other or not is judged; if the two curves intersect with each other, the H90+delta H corresponding to the intersection point is the ultimate dump height when the side slope angle of the refuse dump is beta, a load corresponding to the ultimate dump height is the ultimate bearing capacity of the refuse dump with the weak foundation base; if the two curves do not intersect with each other, the refuse dump has no ultimate dump height. According to the method, the ultimate dump height of the refuse dump is determined according to the bearing capacity angle of the foundation base, and instability of the refuse dump caused by insufficient bearing capacity of the foundation base can be effectively avoided.

Description

A kind of determination method of weakness Based Earth Dump ultimate bearing capacity

Technical field

The invention belongs to strip mining transformation field, particularly to a kind of determination side of weakness Based Earth Dump ultimate bearing capacity Method.

Background technology

Weak substrate is the stable key factor of impact open-pit mine blast, and under the conditions of basement weak, refuse dump highly reaches During a certain marginal value, spot is roused, and then induce refuse dump unstability.The outdoor coal of Pingshou An-tai-bao opening mine, Bao Xile Ore deposit, white tone China mining area one, the weak Based Earth Dump such as No. two, No. three, No. four open coal mines, bundle Kazakhstan nur open coal mines are all sent out Gave birth to bulging at landslide or toe, surface and the larger metaboly such as tension fissure occurred, serious threaten opencut safety, impact is held Continuous normal operation.Base bearing capacity deficiency is to lead to the intrinsic factor of weak Based Earth Dump overall collapse, therefore, weak substrate Refuse dump base bearing capacity calculates and is particularly important.

Your Formula of ultimate bearing capacity of shallow of Prandtl is the classical way calculating bearing capacity in building lot theory, due to meter Calculate principle simple, application is convenient, be often used to calculate refuse dump substrate ultimate bearing capacity, in calculating process, refuse dump load seen Make bar shaped uniform load, do not consider this characteristic distributions of refuse dump delta load, therefore application the method calculates refuse dump substrate Theoretical and imperfection during bearing capacity.

Content of the invention

For the deficiencies in the prior art, the present invention is improved to your Formula of ultimate bearing capacity of shallow of Prandtl, be can use In the weak Based Earth Dump limit height of determination.

According to refuse dump rendering load characteristic distributions, a kind of tool of the determination method of weakness Based Earth Dump ultimate bearing capacity Body step is as follows:

Step 1: calculated using your Formula of ultimate bearing capacity of shallow of Prandtl and do not consider during the delta load of refuse dump side The limit arranges a height of h₉₀.

Step 2: with the high change of refuse dump slope angle and slope, the domatic line position in refuse dump changes, slope is high to be increased To h₉₀During+△ h, determine slip moment increment △ m respectively_SlidingThe resisting moment producing with the functional relationship of △ h, side delta load △m_Anti-' with the functional relationship of △ h, △ h highly reaches h for refuse dump₉₀Height gain afterwards；

Step 2.1, determine slip moment increment △ m_SlidingHighly reach h with refuse dump₉₀The function of height gain △ h afterwards closes System；

Step 2.2, according to refuse dump side slope angle beta and the high h in slope₉₀+ △ h, determines the domatic line position in refuse dump；

Step 2.3, according to the domatic line position in refuse dump, determine the resisting moment △ m that side delta load produces_Anti-' and row Tu Chang highly reaches h₉₀The functional relationship of height gain △ h afterwards.

Step 3: draw △ m respectively_Sliding- △ h and △ m_Anti-'-△ h curve, judge whether two curves intersect, if intersecting, H corresponding to intersection point₉₀+ △ h is the limit height that refuse dump slope angle is during β, and the corresponding load of this limit height is weak base Bottom refuse dump ultimate bearing capacity, if no intersection point, refuse dump does not have limit height.

Advantages of the present invention:

The distribution characteristicss based on refuse dump load for the present invention, are changed to your Formula of ultimate bearing capacity of shallow of Prandtl Enter it is proposed that the determination method of weak Based Earth Dump base bearing capacity, compensate in engineering, weak Based Earth Dump being designed Deficiency with stability study aspect.The method, can from the limit height of base bearing capacity angle-determining weakness Based Earth Dump It is prevented effectively from the refuse dump unstability causing because of base bearing capacity deficiency.

Brief description

Fig. 1 is the refuse dump mechanical model based on your Formula of ultimate bearing capacity of shallow of Prandtl；

Fig. 2 is the refuse dump mechanical model of an embodiment of the present invention；

Fig. 3 is △ m under the different situations of an embodiment of the present invention_Sliding- △ h and △ m_Anti-'-△ h curve, wherein (a) be β= △ m when 60 °_Sliding- △ h and △ m_Anti-'-△ h curve, (b) is △ m during β=45 °_Sliding- △ h and △ m_Anti-'-△ h curve, (c) is β △ m when=36 °_Sliding- △ h and △ m_Anti-'-△ h curve, (d) is △ m during β=16 °_Sliding- △ h and △ m_Anti-'-△ h curve；

Fig. 4 is the weak Based Earth Dump ultimate bearing capacity flow chart that determines method of an embodiment of the present invention.

Specific embodiment

Below in conjunction with the accompanying drawings the specific embodiment of the invention is elaborated.Prandtl that Formula of ultimate bearing capacity of shallow In the power that will act on ground be considered as uniform vertical load, as shown in figure 1, and when calculating refuse dump base bearing capacity, should Consider that refuse dump side has the triangle vertical load of effect against sliding.Public to your ultimate bearing capacity of foundation soil of Prandtl from this aspect Formula improves, and the refuse dump mechanical model of present embodiment is as shown in Figure 2.

Certain open-pit mine blast design slope angle is β=16 °, and substrate is Extra-fine sand for the 4th, dumps thing severe γ₀= 18kpa；Substrate cohesion of soil c=2.1kpa；The internal friction angle of the substrate soil bodyUniform vertical load in the present embodiment Effect foundation width b=6m.

As shown in figure 4, the determination method and step of the weak Based Earth Dump ultimate bearing capacity of present embodiment is as follows:

Step 1: calculated using your Formula of ultimate bearing capacity of shallow of Prandtl and do not consider during the delta load of refuse dump side The limit arranges a height of h₉₀, i.e. the limit height of vertical side slope.

h₉₀=p_u/γ₀=37.375/18=2.076m

Wherein, p_uThe ultimate bearing capacity of substrate, kpa under the conditions of vertical uniform load；

Q base upper portion soil body gravity, kpa；

γ₀Dump thing severe, kn/m³；

WhereinFor the internal friction angle of the substrate soil body, °；

The cohesiveness of the c substrate soil body, kpa；

B foundation width, m；

h₉₀Do not consider that the refuse dump limit row calculating during the delta load of refuse dump side is high, m；

△ h refuse dump highly reaches h₉₀Height gain afterwards, m；

β refuse dump slope angle, °.

If now considering h₉₀The resisting moment m that corresponding side delta load produces₀, then total resisting moment m_Anti-More than cunning Kinetic moment m_Sliding, substrate is in steady statue.

Step 2: with the high change of refuse dump slope angle and slope, the domatic line position in refuse dump changes, slope is high to be increased To h₉₀During+△ h, determine slip moment increment △ m respectively_SlidingThe resisting moment producing with the functional relationship of △ h, side delta load △m_Anti-' with the functional relationship of △ h, △ h highly reaches h for refuse dump₉₀Height gain afterwards.△m_SlidingLinearly close and △ h between System, △ m_Anti-' and △ h between be power function curve relation (whenWhen be cubic curve, whenFor conic section), the two is all the increasing function with △ h as independent variable.When refuse dump continues to increase During high △ h, slip moment increases △ m_Sliding, resisting moment increase △ m_Anti-, the resisting moment △ that corresponding side delta load produces m_Anti-'=△ m_Anti-+m₀, △ m_SlidingWith (△ m_Anti-+m₀) equal, that is, mean m_Anti-With m_SlidingReached balance, refuse dump height now is again For its limit height.

Step 2.1, determine slip moment increment △ m_SlidingHighly reach h with refuse dump₉₀The function of height gain △ h afterwards closes System.

Step 2.2, according to refuse dump side slope angle beta and slope height (h₉₀+ △ h), compares (h₉₀+ △ h)/tan β withDetermine row The domatic line position in native field, as shown in the line of slope 3 in Fig. 2 and line of slope 4.

Step 2.3, according to the domatic line position in refuse dump, determine the resisting moment △ m that side delta load produces_Anti-' and row Tu Chang highly reaches h₉₀The functional relationship of height gain △ h afterwards.The position of refuse dump line of slope can affect △ m_Anti-' with △ h's Functional relation, therefore △ m_Anti-' calculated in two kinds of situation:

When $(h_{90}+\mathrm{\δ}h)/tan\mathrm{\β}\≤\stackrel{\&overbar;}{ai},$

When $(h_{90}+\mathrm{\δ}h)/tan\mathrm{\β}>\stackrel{\&overbar;}{ai},$

Step 3: draw △ m respectively_Sliding- △ h and △ m_Anti-'-△ h curve, as shown in figure 3,1 is △ m_Sliding- △ h curve, 2 is △ m_Anti-'-△ h curve.Wherein Fig. 3 (a) is the refuse dump substrate △ m when slope angle is 60 °_Sliding- △ h curve and △ m_Anti-'-△ h curve Intersecting, intersection point is limit height 2.136m；Fig. 3 (b) provides the refuse dump substrate △ m when slope angle is 45 °_Sliding- △ h curve and △m_Anti-'-△ h curve intersection, intersection point as limit height 2.326m；Fig. 3 (c) provides the refuse dump substrate when slope angle is 36 ° △m_Sliding- △ h curve and △ m_Anti-'-△ h contact of a curve, intersection point as limit height 3.186m；Fig. 3 (d) is given and when slope angle is Substrate △ m in refuse dump when 16 °_Sliding- △ h curve and △ m_Anti-'-△ h curve is non-intersect, resisting moment is very big, and now refuse dump does not have Limit height, △ m_Anti-' it is far longer than △ m_SlidingAnd increase with slope height and infinitely increase, that is, height can infinitely be arranged in refuse dump.

Claims (1)

1. a kind of determination method of weakness Based Earth Dump ultimate bearing capacity, comprises the following steps:

Step 1: calculate the limit not considered during the delta load of refuse dump side using your Formula of ultimate bearing capacity of shallow of Prandtl The a height of h of heap₉₀；

Step 2: with the high change of refuse dump slope angle and slope, the domatic line position in refuse dump changes, and slope height increases to h₉₀+ During δ h, determine slip moment increment δ m respectively_SlidingThe resisting moment δ m producing with the functional relationship of δ h, side delta load_Anti-′ With the functional relationship of δ h, δ h highly reaches h for refuse dump₉₀Height gain afterwards；

Step 3: draw δ m respectively_Sliding- δ h and δ m_Anti-'-δ h curve, judges whether two curves intersect, if intersecting, intersection point Corresponding h₉₀+ δ h is the limit height that refuse dump slope angle is during β, and the corresponding load of this limit height is weak substrate row Native field ultimate bearing capacity, if no intersection point, refuse dump does not have limit height；

It is characterized in that: described step 2 specifically comprises the following steps that

Step 2.1, determine slip moment increment δ m_SlidingHighly reach h with refuse dump₉₀The functional relationship of height gain δ h afterwards；

Step 2.2, according to refuse dump side slope angle beta and the high h in slope₉₀+ δ h, determines the domatic line position in refuse dump；

Step 2.3, according to domatic line position, determine the resisting moment δ m that side delta load produces_Anti-' highly reach with refuse dump To h₉₀The functional relationship of height gain δ h afterwards.